1
|
Rissanen APE, Mikkola T, Gagnon DD, Lehtonen E, Lukkarinen S, Peltonen JE. Wagner diagram for modeling O 2pathway-calculation and graphical display by the Helsinki O 2Pathway Tool. Physiol Meas 2024; 45:055028. [PMID: 38749432 DOI: 10.1088/1361-6579/ad4c36] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Accepted: 05/15/2024] [Indexed: 06/06/2024]
Abstract
Objective.Maximal O2uptake (V˙O2max) reflects the individual's maximal rate of O2transport and utilization through the integrated whole-body pathway composed of the lungs, heart, blood, circulation, and metabolically active tissues. As such,V˙O2maxis strongly associated with physical capacity as well as overall health and thus acts as one predictor of physical performance and as a vital sign in determination of status and progress of numerous clinical conditions. Quantifying the contribution of single parts of the multistep O2pathway toV˙O2maxprovides mechanistic insights into exercise (in)tolerance and into therapy-, training-, or disuse-induced adaptations at individual or group levels. We developed a desktop application (Helsinki O2Pathway Tool-HO2PT) to model numerical and graphical display of the O2pathway based on the 'Wagner diagram' originally formulated by Peter D. Wagner and his colleagues.Approach.The HO2PT was developed and programmed in Python to integrate the Fick principle and Fick's law of diffusion into a computational system to import, calculate, graphically display, and export variables of the Wagner diagram.Main results.The HO2PT models O2pathway both numerically and graphically according to the Wagner diagram and pertains to conditions under which the mitochondrial oxidative capacity of metabolically active tissues exceeds the capacity of the O2transport system to deliver O2to the mitochondria. The tool is based on the Python open source code and libraries and freely and publicly available online for Windows, macOS, and Linux operating systems.Significance.The HO2PT offers a novel functional and demonstrative platform for those interested in examiningV˙O2maxand its determinants by using the Wagner diagram. It will improve access to and usability of Wagner's and his colleagues' integrated physiological model and thereby benefit users across the wide spectrum of contexts such as scientific research, education, exercise testing, sports coaching, and clinical medicine.
Collapse
Affiliation(s)
- Antti-Pekka E Rissanen
- Helsinki Sports and Exercise Medicine Clinic, Foundation for Sports and Exercise Medicine (HULA), Helsinki, Finland
- Sports and Exercise Medicine, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Tom Mikkola
- Helsinki Sports and Exercise Medicine Clinic, Foundation for Sports and Exercise Medicine (HULA), Helsinki, Finland
- School of Information and Communication Technology, Metropolia University of Applied Sciences, Helsinki, Finland
| | - Dominique D Gagnon
- Helsinki Sports and Exercise Medicine Clinic, Foundation for Sports and Exercise Medicine (HULA), Helsinki, Finland
- Sports and Exercise Medicine, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Faculty of Sports and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
- School of Kinesiology and Health Sciences, Laurentian University, Sudbury, ON, Canada
| | - Elias Lehtonen
- Helsinki Sports and Exercise Medicine Clinic, Foundation for Sports and Exercise Medicine (HULA), Helsinki, Finland
- Sports and Exercise Medicine, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Sakari Lukkarinen
- School of Information and Communication Technology, Metropolia University of Applied Sciences, Helsinki, Finland
| | - Juha E Peltonen
- Helsinki Sports and Exercise Medicine Clinic, Foundation for Sports and Exercise Medicine (HULA), Helsinki, Finland
- Sports and Exercise Medicine, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| |
Collapse
|
2
|
Mastrandrea CJ, Hedge ET, Hughson RL. The detrimental effects of bedrest: Premature cardiovascular aging and dysfunction. Can J Cardiol 2024:S0828-282X(24)00395-7. [PMID: 38759726 DOI: 10.1016/j.cjca.2024.05.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 05/08/2024] [Accepted: 05/09/2024] [Indexed: 05/19/2024] Open
Abstract
Bedrest as an experimental paradigm or as an in-patient stay for medical reasons has negative consequences for cardiovascular health. The effects of severe inactivity parallel many of the changes experienced with natural aging but over a much shorter duration. Cardiac function is reduced, arteries stiffen, neural reflex responses are impaired, and metabolic and oxidative stress responses impose burden on the heart and vascular systems. The impact of these changes is revealed in studies of integrative function. Aerobic fitness progressively deteriorates with bedrest and tolerance of upright posture is rapidly impaired. This review considers the similarities between aging and bedrest-induced cardiovascular deconditioning. We concur with many recent clinical recommendations that early and regular mobility with upright posture will reduce likelihood of hospital-associated disability related to bedrest.
Collapse
Affiliation(s)
- Carmelo J Mastrandrea
- Schlegel-UW Research Institute for Aging, Waterloo, Canada; Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Canada
| | - Eric T Hedge
- Schlegel-UW Research Institute for Aging, Waterloo, Canada; Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Canada
| | | |
Collapse
|
3
|
Haddad T, Spence AL, Peiffer J, Blain GM, Brisswalter J, Abbiss CR. The Improvement in Exercise Performance during Reduced Muscle Mass Exercise is Associated with an Increase in Femoral Blood Flow in Older and Younger Endurance-Trained Athletes. J Sports Sci Med 2024; 23:46-55. [PMID: 38455445 PMCID: PMC10915611 DOI: 10.52082/jssm.2024.46] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 12/01/2023] [Indexed: 03/09/2024]
Abstract
This study investigated whether the improved performance observed with maximal self-paced single-leg (SL), compared with double-leg (DL) cycling, is associated with enhanced femoral blood flow and/or altered tissue oxygenation. The hyperaemic response to exercise was assessed in younger and older athletes. Power output was measured in 12 older (65 ± 4 y) and 12 younger (35 ± 5 y) endurance-trained individuals performing 2 x 3 min maximal self-paced exercise using SL and DL cycling. Blood flow (BF) in the femoral artery was assessed using Doppler ultrasound and muscle oxygenation was measured using near-infrared spectroscopy on the vastus lateralis. SL cycling elicited a greater power output (295 ± 83 vs 265 ± 70 W, P < 0.001) and peak femoral BF (1749.1 ± 533.3 vs 1329.7 ± 391.7 ml/min, P < 0.001) compared with DL cycling. Older individuals had a lower peak BF in response to exercise (1355.4 ± 385.8 vs 1765.2 ± 559.6 ml/min, P = 0.019) compared with younger individuals. Peak BF in response to exercise was correlated with power output during SL (r = 0.655, P = 0.002) and DL (r = 0.666, P = 0.001) cycling. The greater exercise performance during SL compared with DL cycling may be partly explained by a greater hyperaemic response when reducing active muscle mass. Despite regular endurance training, older athletes had a lower femoral BF in response to maximal self-paced exercise compared with younger athletes.
Collapse
Affiliation(s)
- Toni Haddad
- Centre for Human Performance, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
- Université Côte d'Azur, LAMHESS, France
| | - Angela L Spence
- Curtin School of Allied Health, Exercise and Sport Science Discipline, Curtin University, WA, Australia
- Curtin Health Innovation Research Institute, Curtin University, WA, Australia
| | - Jeremiah Peiffer
- Centre for Healthy Ageing, Murdoch University, Murdoch, WA, Australia
| | | | | | - Chris R Abbiss
- Centre for Human Performance, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
| |
Collapse
|
4
|
Cheung CP, Baker RE, Coates AM, Burr JF. Cannabis containing THC impairs 20-min cycling time trial performance irrespective of the method of inhalation. J Appl Physiol (1985) 2024; 136:583-591. [PMID: 38299223 DOI: 10.1152/japplphysiol.00757.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 01/25/2024] [Accepted: 01/26/2024] [Indexed: 02/02/2024] Open
Abstract
Herein, we examine the human exercise response following cannabis inhalation, taking into consideration varied cannabinoid concentrations and different inhalation methods. A semirandomized crossover study design was used, with measures of perceived exertion and physiological responses to submaximal and maximal exercise. Participants (n = 14, 9 males 5 females) completed exercise after 1) smoking Δ-9-tetrahydrocannabinol (THC)-predominant cannabis (S-THC), 2) inhaling aerosol (vaporizing) from THC-predominant cannabis (V-THC), 3) inhaling aerosol from cannabidiol (CBD)-predominant cannabis (V-CBD), or 4) under control conditions. All exercise was performed on a cycle ergometer, with submaximal testing performed at 100 W followed by an evaluation of maximal exercise performance using an all-out 20-min time trial. Metabolism was characterized via the analysis of expired gases while subjective ratings of perceived exertion (RPE) were reported. During submaximal cycling, heart rate was higher during S-THC and V-THC compared with both control and V-CBD (all P < 0.02). During maximal exercise, V̇e was lower in V-THC compared with control, S-THC, and V-CBD (all P < 0.03), as was S-THC compared with control (P < 0.05). Both V̇o2 and RPE were similar between conditions during maximal exercise (both P > 0.1). Mean power output during the 20-min time trial was significantly lower in the S-THC and V-THC conditions compared with both control and V-CBD (all P < 0.04). Cannabis containing THC alters the physiological response to maximal and submaximal exercise, largely independent of the inhalation method. THC-containing cannabis negatively impacts vigorous exercise performance during a sustained 20-min effort, likely due to physiological and psychotropic effects. Inhalation of cannabis devoid of THC and primarily containing CBD has little physiological effect on the exercise response or performance.NEW & NOTEWORTHY Inhalation of cannabis containing THC alters physiological responses to both submaximal and maximal exercise and reduces mean power output during a 20-min time trial, regardless of whether it is inhaled as smoke or aerosol. In contrast, cannabis devoid of THC and predominantly containing CBD has no effect on physiological responses to exercise or performance.
Collapse
Affiliation(s)
- Christian P Cheung
- Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Ryleigh E Baker
- Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Alexandra M Coates
- Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Jamie F Burr
- Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| |
Collapse
|
5
|
Gifford JR, Blackmon C, Hales K, Hinkle LJ, Richards S. Overdot and overline annotation must be understood to accurately interpret V.O 2MAX physiology with the Fick formula. Front Physiol 2024; 15:1359119. [PMID: 38444762 PMCID: PMC10912163 DOI: 10.3389/fphys.2024.1359119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 01/26/2024] [Indexed: 03/07/2024] Open
Abstract
Few formulas have been used in exercise physiology as extensively as the Fick formula, which calculates the rate of oxygen consumption (i.e., V.O2) as the product of cardiac output (Q.) and the difference in oxygen content in arterial and mixed venous blood (Δav ¯ O2). Unfortunately, the physiology of maximum V.O2 (V.O2MAX) is often misinterpreted due to a lack of appreciation for the limitations represented by the oft-ignored superscript annotations in the Fick formula. The purpose of this perspective is to explain the meaning of the superscript annotations and highlight how such annotations influence proper interpretation of V.O2MAX physiology with the Fick formula. First, we explain the significance of the overdots above V.O2 and Q., which indicate a measure per unit of time. As we will show, the presence of an overdot above Q. and lack of one above Δav ¯ O2 denotes they are different types of ratios and should be interpreted in the context of one another-not in contrast to each other as is commonplace. Second, we discuss the significance of the overline above the "v ¯ " in Δav ¯ O2, which indicates the venous sample is an average of blood that comes from mixed sources. The mixed nature of the venous sample has major implications for interpreting the influence of oxygen diffusion and blood flow heterogeneity on V.O2MAX. Ultimately, we give recommendations and insights for using the Fick formula to calculate V.O2 and interpret V.O2MAX physiology.
Collapse
Affiliation(s)
- Jayson R. Gifford
- Department of Exercise Sciences, Brigham Young University, Provo, UT, United States
- Program of Gerontology, Brigham Young University, Provo, UT, United States
| | - Christina Blackmon
- Department of Exercise Sciences, Brigham Young University, Provo, UT, United States
| | - Katelynn Hales
- Department of Exercise Sciences, Brigham Young University, Provo, UT, United States
| | - Lee J. Hinkle
- Department of Exercise Sciences, Brigham Young University, Provo, UT, United States
| | - Shay Richards
- Department of Exercise Sciences, Brigham Young University, Provo, UT, United States
| |
Collapse
|
6
|
Dorff A, Bradford C, Hunsaker A, Atkinson J, Rhees J, Leach OK, Gifford JR. Vascular dysfunction and the age-related decline in critical power. Exp Physiol 2024; 109:240-254. [PMID: 37934136 PMCID: PMC10988715 DOI: 10.1113/ep091571] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 10/18/2023] [Indexed: 11/08/2023]
Abstract
Ageing results in lower exercise tolerance, manifested as decreased critical power (CP). We examined whether the age-related decrease in CP occurs independently of changes in muscle mass and whether it is related to impaired vascular function. Ten older (63.1 ± 2.5 years) and 10 younger (24.4 ± 4.0 years) physically active volunteers participated. Physical activity was measured with accelerometry. Leg muscle mass was quantified with dual X-ray absorptiometry. The CP and maximum power during a graded exercise test (PGXT ) of single-leg knee-extension exercise were determined over the course of four visits. During a fifth visit, vascular function of the leg was assessed with passive leg movement (PLM) hyperaemia and leg blood flow and vascular conductance during knee-extension exercise at 10 W, 20 W, slightly below CP (90% CP) and PGXT . Despite not differing in leg lean mass (P = 0.901) and physical activity (e.g., steps per day, P = 0.735), older subjects had ∼30% lower mass-specific CP (old = 3.20 ± 0.94 W kg-1 vs. young = 4.60 ± 0.87 W kg-1 ; P < 0.001). The PLM-induced hyperaemia and leg blood flow and/or conductance were blunted in the old at 20 W, 90% CP and PGXT (P < 0.05). When normalized for leg muscle mass, CP was strongly correlated with PLM-induced hyperaemia (R2 = 0.52; P < 0.001) and vascular conductance during knee-extension exercise at 20 W (R2 = 0.34; P = 0.014) and 90% CP (R2 = 0.39; P = 0.004). In conclusion, the age-related decline in CP is not only an issue of muscle quantity, but also of impaired muscle quality that corresponds to impaired vascular function.
Collapse
Affiliation(s)
- Abigail Dorff
- Department of Exercise SciencesBrigham Young UniversityProvoUtahUSA
- Program of GerontologyBrigham Young UniversityProvoUtahUSA
| | - Christy Bradford
- Department of Exercise SciencesBrigham Young UniversityProvoUtahUSA
| | - Ashley Hunsaker
- Department of Exercise SciencesBrigham Young UniversityProvoUtahUSA
| | - Jake Atkinson
- Department of Exercise SciencesBrigham Young UniversityProvoUtahUSA
| | - Joshua Rhees
- Department of Exercise SciencesBrigham Young UniversityProvoUtahUSA
| | - Olivia K. Leach
- Department of Exercise SciencesBrigham Young UniversityProvoUtahUSA
- Program of GerontologyBrigham Young UniversityProvoUtahUSA
| | - Jayson R. Gifford
- Department of Exercise SciencesBrigham Young UniversityProvoUtahUSA
- Program of GerontologyBrigham Young UniversityProvoUtahUSA
| |
Collapse
|
7
|
Tripp TR, McDougall RM, Frankish BP, Wiley JP, Lun V, MacInnis MJ. Contraction intensity affects NIRS-derived skeletal muscle oxidative capacity but not its relationships to mitochondrial protein content or aerobic fitness. J Appl Physiol (1985) 2024; 136:298-312. [PMID: 38059287 DOI: 10.1152/japplphysiol.00342.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 11/16/2023] [Accepted: 12/02/2023] [Indexed: 12/08/2023] Open
Abstract
To further refine the near-infrared spectroscopy (NIRS)-derived measure of skeletal muscle oxidative capacity in humans, we sought to determine whether the exercise stimulus intensity affected the τ value and/or influenced the magnitude of correlations with in vitro measures of mitochondrial content and in vivo indices of exercise performance. Males (n = 12) and females (n = 12), matched for maximal aerobic fitness per fat-free mass, completed NIRS-derived skeletal muscle oxidative capacity tests for the vastus lateralis following repeated contractions at 40% (τ40) and 100% (τ100) of maximum voluntary contraction, underwent a skeletal muscle biopsy of the same muscle, and performed multiple intermittent isometric knee extension tests to task failure to establish critical torque (CT). The value of τ100 (34.4 ± 7.0 s) was greater than τ40 (24.2 ± 6.9 s, P < 0.001), but the values were correlated (r = 0.688; P < 0.001). The values of τ40 (r = -0.692, P < 0.001) and τ100 (r = -0.488, P = 0.016) correlated with myosin heavy chain I percentage and several markers of mitochondrial content, including COX II protein content in whole muscle (τ40: r = -0.547, P = 0.006; τ100: r = -0.466, P = 0.022), type I pooled fibers (τ40: r = -0.547, P = 0.006; τ100: r = -0.547, P = 0.006), and type II pooled fibers (τ40: r = -0.516, P = 0.009; τ100: r = -0.635, P = 0.001). The value of τ40 (r = -0.702, P < 0.001), but not τ100 (r = -0.378, P = 0.083) correlated with critical torque (CT); however, neither value correlated with W' (τ40: r = 0.071, P = 0.753; τ100: r = 0.054, P = 0.812). Overall, the NIRS method of assessing skeletal muscle oxidative capacity is sensitive to the intensity of skeletal muscle contraction but maintains relationships to whole body fitness, isolated limb critical intensity, and mitochondrial content regardless of intensity.NEW & NOTEWORTHY Skeletal muscle oxidative capacity measured using near-infrared spectroscopy (NIRS) was lower following high-intensity compared with low-intensity isometric knee extension contractions. At both intensities, skeletal muscle oxidative capacity was correlated with protein markers of mitochondrial content (in whole muscle and pooled type I and type II muscle fibers) and critical torque. These findings highlight the importance of standardizing contraction intensity while using the NIRS method with isometric contractions and further demonstrate its validity.
Collapse
Affiliation(s)
- Thomas R Tripp
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | | | | | - J Preston Wiley
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
- Faculty of Kinesiology, University of Calgary Sport Medicine Centre, Calgary, Alberta, Canada
| | - Victor Lun
- Faculty of Kinesiology, University of Calgary Sport Medicine Centre, Calgary, Alberta, Canada
| | - Martin J MacInnis
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| |
Collapse
|
8
|
Broxterman RM, Wagner PD, Richardson RS. Endurance exercise training changes the limitation on muscle V ̇ O 2 max ${\dot{V}}_{{{\mathrm{O}}}_{\mathrm{2}}{\mathrm{max}}}$ in normoxia from the capacity to utilize O 2 to the capacity to transport O 2. J Physiol 2024; 602:445-459. [PMID: 38048175 PMCID: PMC10841684 DOI: 10.1113/jp285650] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 11/14/2023] [Indexed: 12/06/2023] Open
Abstract
Maximal oxygen (O2 ) uptake (V ̇ O 2 max ${\dot{V}}_{{{\mathrm{O}}}_{\mathrm{2}}{\mathrm{max}}}$ ) is an important parameter with utility in health and disease. However, the relative importance of O2 transport and utilization capacities in limiting muscleV ̇ O 2 max ${\dot{V}}_{{{\mathrm{O}}}_{\mathrm{2}}{\mathrm{max}}}$ before and after endurance exercise training is not well understood. Therefore, the present study aimed to identify the mechanisms determining muscleV ̇ O 2 max ${\dot{V}}_{{{\mathrm{O}}}_{\mathrm{2}}{\mathrm{max}}}$ pre- and post-endurance exercise training in initially sedentary participants. In five initially sedentary young males, radial arterial and femoral venousP O 2 ${P}_{{{\mathrm{O}}}_{\mathrm{2}}}$ (blood samples), leg blood flow (thermodilution), and myoglobin (Mb) desaturation (1 H nuclear magnetic resonance spectroscopy) were measured during maximal single-leg knee-extensor exercise (KE) breathing either 12%, 21% or 100% O2 both pre and post 8 weeks of KE training (1 h, 3 times per week). Mb desaturation was converted to intracellularP O 2 ${P}_{{{\mathrm{O}}}_{\mathrm{2}}}$ using an O2 half-saturation pressure of 3.2 mmHg. Pre-training muscleV ̇ O 2 max ${\dot{V}}_{{{\mathrm{O}}}_{\mathrm{2}}{\mathrm{max}}}$ was not significantly different across inspired O2 conditions (12%: 0.47 ± 0.10; 21%: 0.52 ± 0.13; 100%: 0.54 ± 0.01 L min-1 , all q > 0.174), despite significantly greater muscle mean capillary-intracellularP O 2 ${P}_{{{\mathrm{O}}}_{\mathrm{2}}}$ gradients in normoxia (34 ± 3 mmHg) and hyperoxia (40 ± 7 mmHg) than hypoxia (29 ± 5 mmHg, both q < 0.024). Post-training muscleV ̇ O 2 max ${\dot{V}}_{{{\mathrm{O}}}_{\mathrm{2}}{\mathrm{max}}}$ was significantly different across all inspired O2 conditions (12%: 0.59 ± 0.11; 21%: 0.68 ± 0.11; 100%: 0.76 ± 0.09 mmHg, all q < 0.035), as were the muscle mean capillary-intracellularP O 2 ${P}_{{{\mathrm{O}}}_{\mathrm{2}}}$ gradients (12%: 32 ± 2; 21%: 37 ± 2; 100%: 45 ± 7 mmHg, all q < 0.029). In these initially sedentary participants, endurance exercise training changed the basis of limitation on muscleV ̇ O 2 max ${\dot{V}}_{{{\mathrm{O}}}_{\mathrm{2}}{\mathrm{max}}}$ in normoxia from the mitochondrial capacity to utilize O2 to the capacity to transport O2 to the mitochondria. KEY POINTS: Maximal O2 uptake is an important parameter with utility in health and disease. The relative importance of O2 transport and utilization capacities in limiting muscle maximal O2 uptake before and after endurance exercise training is not well understood. We combined the direct measurement of active muscle maximal O2 uptake with the measurement of muscle intracellularP O 2 ${P}_{{{\mathrm{O}}}_{\mathrm{2}}}$ before and after 8 weeks of endurance exercise training. We show that increasing O2 availability did not increase muscle maximal O2 uptake before training, whereas increasing O2 availability did increase muscle maximal O2 uptake after training. The results suggest that, in these initially sedentary participants, endurance exercise training changed the basis of limitation on muscle maximal O2 uptake in normoxia from the mitochondrial capacity to utilize O2 to the capacity to transport O2 to the mitochondria.
Collapse
Affiliation(s)
- Ryan M. Broxterman
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah
- Geriatric Research, Education, and Clinical Center, VA Medical Center, Salt Lake City, Utah
| | - Peter D. Wagner
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Russell S. Richardson
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah
- Geriatric Research, Education, and Clinical Center, VA Medical Center, Salt Lake City, Utah
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| |
Collapse
|
9
|
Bartlett MF, Oneglia AP, Ricard MD, Siddiqui A, Englund EK, Buckley EM, Hueber DM, Nelson MD. DCS blood flow index underestimates skeletal muscle perfusion in vivo: rationale and early evidence for the NIRS-DCS perfusion index. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:020501. [PMID: 38322728 PMCID: PMC10844820 DOI: 10.1117/1.jbo.29.2.020501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/30/2023] [Accepted: 01/11/2024] [Indexed: 02/08/2024]
Abstract
Significance Diffuse correlation spectroscopy (DCS) permits non-invasive assessment of skeletal muscle blood flow but may misestimate changes in muscle perfusion. Aim We aimed to highlight recent evidence that DCS blood flow index (BFI) misestimates changes in muscle blood flow during physiological perturbation and to introduce a novel approach that adjusts BFI for estimated changes in vasodilation. Approach We measured changes in muscle BFI during quadriceps and forearm exercises using DCS, the latter of which were adjusted for estimated changes in microvascular flow area and then compared to Doppler ultrasound in the brachial artery. Then, we compared adjusted BFI- and arterial spin labeling (ASL) MRI measures of gastrocnemius blood flow during reactive hyperemia and plantar flexion exercise. Results We observed little-to-no change in quadriceps BFI during maximal-effort exercise. Similarly, forearm BFI was modestly increased during handgrip exercise, but the magnitude was significantly lower than measured by Doppler ultrasound in the brachial artery. However, this difference was ameliorated after adjusting BFI for estimated changes in microvascular flow area. Similar observations were also observed in the gastrocnemius when directly comparing the adjusted BFI values to ASL-MRI. Conclusions Adjusting BFI for estimated changes in microvascular flow area may improve DCS estimates of muscle blood flow, but further study is needed to validate these methods moving forward.
Collapse
Affiliation(s)
- Miles F Bartlett
- University of Texas at Arlington, Arlington, Texas, United States
- Bartlett Sciences LLC, Dallas, Texas, United States
| | - Andrew P Oneglia
- University of Texas at Arlington, Arlington, Texas, United States
| | - Mark D Ricard
- University of Texas at Arlington, Arlington, Texas, United States
| | | | - Erin K Englund
- University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Erin M Buckley
- Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States
| | | | - Michael D Nelson
- University of Texas at Arlington, Arlington, Texas, United States
| |
Collapse
|
10
|
Thompson KMA, Gamble ASD, Kontro H, Lee JB, Burr JF. Low- and high-volume blood-flow restriction treadmill walking both improve maximal aerobic capacity independently of blood volume. Scand J Med Sci Sports 2024; 34:e14534. [PMID: 37961932 DOI: 10.1111/sms.14534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 10/22/2023] [Accepted: 10/26/2023] [Indexed: 11/15/2023]
Abstract
AIM Assess the effect of low- and high-volume blood flow restriction training (BFR) on maximal aerobic capacity (VO2 max) and determine if alteration in VO2 max is mediated through changes in hemoglobin mass (Hbmass) and blood volume. METHODS Participants' Hbmass (CO-rebreathe), single, and double-leg VO2 max and blood volume regulating hormonal responses (renin and copeptin) were measured before and after BFR training. Training consisted of treadmill walking either (1) twice-daily for 4week (CON and BFRHV ) or (2) twice-weekly for 6week (BFRLV ). Each session consisted of five intervals (3 min, 5% incline, 5 km/h, 100% of lowest occlusion pressure), with 1 min of standing rest between sets. RESULTS VO2 max increased using both training exposures, in as quickly as 2-weeks (BFRLV baseline to 4week: +315 ± 241 mL (8.7%), p = 0.02; BFRHV baseline to 2week: +360 ± 261 mL (7.9%), p < 0.01), for the BFRLV and BFRHV groups, with no change in CON. Single- and double-leg VO2 max improved proportionately (single/double-leg VO2 max ratio: BFRLV 78 ± 4.9-78 ± 5.8%, BFRHV 79 ± 6.5-77 ± 6.5%), suggesting that the mechanism for increased VO2 max is not solely limited to central or peripheral adaptations. Hbmass remained unchanged across groups (CON: +10.2 ± 34 g, BFRLV : +6.6 ± 42 g, BFRHV : +3.2 ± 44 g; p = 0.9), despite a significant release of blood volume regulating hormones after initial BFR exposure (renin +20.8 ± 21.9 ng/L, p < 0.01; copeptin +22.0 ± 23.8 pmol/L, p < 0.01), which was blunted following BFRHV training (renin: +13.4 ± 12.4 ng/L, p = 0.09; copeptin: +1.9 ± 1.7 pmol/L, p = 0.98). CONCLUSION BFR treadmill walking increases VO2 max irrespective of changes in Hbmass or blood volume despite a large release of blood volume regulating hormones in response to BFR treadmill walking.
Collapse
Affiliation(s)
- K M A Thompson
- Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - A S D Gamble
- Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - H Kontro
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - J B Lee
- Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - J F Burr
- Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| |
Collapse
|
11
|
Bostad W, Williams JS, Van Berkel EK, Richards DL, MacDonald MJ, Gibala MJ. Biological sex does not influence the peak cardiac output response to twelve weeks of sprint interval training. Sci Rep 2023; 13:22995. [PMID: 38151488 PMCID: PMC10752867 DOI: 10.1038/s41598-023-50016-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 12/14/2023] [Indexed: 12/29/2023] Open
Abstract
Sprint interval training (SIT) increases peak oxygen uptake (V̇O2peak) but the mechanistic basis is unclear. We have reported that 12 wk of SIT increased V̇O2peak and peak cardiac output (Q̇peak) and the changes in these variables were correlated. An exploratory analysis suggested that Q̇peak increased in males but not females. The present study incorporated best practices to examine the potential influence of biological sex on the Q̇peak response to SIT. Male and female participants (n = 10 each; 21 ± 4 y) performed 33 ± 2 sessions of SIT over 12 wk. Each 10-min session involved 3 × 20-s 'all-out' sprints on an ergometer. V̇O2peak increased after SIT (3.16 ± 1.0 vs. 2.89 ± 1.0 L/min, η2p = 0.53, p < 0.001) with no sex × time interaction (p = 0.61). Q̇peak was unchanged after training (15.2 ± 3.3 vs. 15.1 ± 3.0 L/min, p = 0.85), in contrast to our previous study. The peak estimated arteriovenous oxygen difference increased after training (204 ± 30 vs. 187 ± 36 ml/L, p = 0.006). There was no effect of training or sex on measures of endothelial function. We conclude that 12 wk of SIT increases V̇O2peak but the mechanistic basis remains unclear. The capacity of inert gas rebreathing to assess changes in Q̇peak may be limited and invasive studies that use more direct measures are needed.
Collapse
Affiliation(s)
- William Bostad
- Department of Kinesiology, McMaster University, Ivor Wynne Centre, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada
| | - Jennifer S Williams
- Department of Kinesiology, McMaster University, Ivor Wynne Centre, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada
| | - Emily K Van Berkel
- Department of Kinesiology, McMaster University, Ivor Wynne Centre, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada
| | - Douglas L Richards
- Department of Medicine, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada
| | - Maureen J MacDonald
- Department of Kinesiology, McMaster University, Ivor Wynne Centre, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada
| | - Martin J Gibala
- Department of Kinesiology, McMaster University, Ivor Wynne Centre, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada.
| |
Collapse
|
12
|
McDougall RM, Tripp TR, Frankish BP, Doyle-Baker PK, Lun V, Wiley JP, Aboodarda SJ, MacInnis MJ. The influence of skeletal muscle mitochondria and sex on critical torque and performance fatiguability in humans. J Physiol 2023; 601:5295-5316. [PMID: 37902588 DOI: 10.1113/jp284958] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 10/04/2023] [Indexed: 10/31/2023] Open
Abstract
Critical torque (CT) represents the highest oxidative steady state for intermittent knee extensor exercise, but the extent to which it is influenced by skeletal muscle mitochondria and sex is unclear. Vastus lateralis muscle biopsy samples were collected from 12 females and 12 males -matched for relative maximal oxygen uptake normalized to fat-free mass (FFM) (F: 57.3 (7.5) ml (kg FFM)-1 min-1 ; M: 56.8 (7.6) ml (kg FFM)-1 min-1 ; P = 0.856) - prior to CT determination and performance fatiguability trials. Males had a lower proportion of myosin heavy chain (MHC) I isoform (40.6 (18.4)%) compared to females (59.5 (18.9)%; P = 0.021), but MHC IIa and IIx isoform distributions and protein markers of mitochondrial content were not different between sexes (P > 0.05). When normalized to maximum voluntary contraction (MVC), the relative CT (F: 42.9 (8.3)%; M: 37.9 (9.0)%; P = 0.172) and curvature constant, W' (F: 26.6 (11.0) N m s (N m)-1 ; M: 26.4 (6.5) N m s (N m)-1 ; P = 0.962) were not significantly different between sexes. All protein biomarkers of skeletal muscle mitochondrial content, as well as the proportion of MHC I isoform, positively correlated with relative CT (0.48 < r < 0.70; P < 0.05), and the proportion of MHC IIx isoform correlated positively with relative W' (r = 0.57; P = 0.007). Indices of performance fatiguability were not different between males and females for MVC- and CT-controlled trials (P > 0.05). Greater mitochondrial protein abundance was associated with attenuated declines in potentiated twitch torque for exercise at 60% MVC (P < 0.05); however, the influence of mitochondrial protein abundance on performance fatiguability was reduced when exercise was prescribed relative to CT. Whether these findings translate to whole-body exercise requires additional research. KEY POINTS: The quadriceps critical torque represents the highest intensity of intermittent knee extensor exercise for which an oxidative steady state is attainable, but its relationship with skeletal muscle mitochondrial protein abundance is unknown. Matching males and females for maximal oxygen uptake relative to fat-free mass facilitates investigations of sex differences in exercise physiology, but studies that have compared critical torque and performance fatiguability during intermittent knee extensor exercise have not ensured equal aerobic fitness between sexes. Skeletal muscle mitochondrial protein abundance was correlated with critical torque and fatigue resistance for exercise prescribed relative to maximum voluntary contraction but not for exercise performed relative to the critical torque. Differences between sexes in critical torque, skeletal muscle mitochondrial protein abundance and performance fatiguability were not statistically significant. Our results suggest that skeletal muscle mitochondrial protein abundance may contribute to fatigue resistance by influencing the critical intensity of exercise.
Collapse
Affiliation(s)
| | - Thomas R Tripp
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | | | | | - Victor Lun
- Faculty of Kinesiology, University of Calgary Sport Medicine Centre, University of Calgary, Calgary, Alberta, Canada
| | - J Preston Wiley
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
- Faculty of Kinesiology, University of Calgary Sport Medicine Centre, University of Calgary, Calgary, Alberta, Canada
| | - S Jalal Aboodarda
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Martin J MacInnis
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| |
Collapse
|
13
|
Leszczynski EC, Schwartz NE, McPeek AC, Currie KD, Ferguson DP, Garland T. Selectively breeding for high voluntary physical activity in female mice does not bestow inherent characteristics that resemble eccentric remodeling of the heart, but the mini-muscle phenotype does. SPORTS MEDICINE AND HEALTH SCIENCE 2023; 5:205-212. [PMID: 37753423 PMCID: PMC10518799 DOI: 10.1016/j.smhs.2023.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 05/18/2023] [Accepted: 07/05/2023] [Indexed: 09/28/2023] Open
Abstract
Physical activity engagement results in a variety of positive health outcomes, including a reduction in cardiovascular disease risk partially due to eccentric remodeling of the heart. The purpose of this investigation was to determine if four replicate lines of High Runner mice that have been selectively bred for voluntary exercise on wheels have a cardiac phenotype that resembles the outcome of eccentric remodeling. Adult females (average age 55 days) from the 4 High Runner and 4 non-selected control lines were anaesthetized via vaporized isoflurane, then echocardiographic images were collected and analyzed for structural and functional differences. High Runner mice in general had lower ejection fractions compared to control mice lines (2-tailed p = 0.023 6) and tended to have thicker walls of the anterior portion of the left ventricle (p = 0.065). However, a subset of the High Runner individuals, termed mini-muscle mice, had greater ejection fraction (p = 0.000 6), fractional shortening percentage (p < 0.000 1), and ventricular mass at dissection (p < 0.002 7 with body mass as a covariate) compared to non-mini muscle mice. Mice from replicate lines bred for high voluntary exercise did not all have inherent positive cardiac functional or structural characteristics, although a genetically unique subset of mini-muscle individuals did have greater functional cardiac characteristics, which in conjunction with their previously described peripheral aerobic enhancements (e.g., increased capillarity) would partially account for their increased V ˙ O2max.
Collapse
Affiliation(s)
| | - Nicole E. Schwartz
- Department of Evolution, Ecology, and Organismal Biology, University of California Riverside, Riverside, CA, USA
| | - Ashley C. McPeek
- Department of Kinesiology, Michigan State University, East Lansing, MI, USA
| | | | - David P. Ferguson
- Department of Kinesiology, Michigan State University, East Lansing, MI, USA
| | - Theodore Garland
- Department of Evolution, Ecology, and Organismal Biology, University of California Riverside, Riverside, CA, USA
| |
Collapse
|
14
|
Mendelson AA, Erickson D, Villar R. The role of the microcirculation and integrative cardiovascular physiology in the pathogenesis of ICU-acquired weakness. Front Physiol 2023; 14:1170429. [PMID: 37234410 PMCID: PMC10206327 DOI: 10.3389/fphys.2023.1170429] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 04/28/2023] [Indexed: 05/28/2023] Open
Abstract
Skeletal muscle dysfunction after critical illness, defined as ICU-acquired weakness (ICU-AW), is a complex and multifactorial syndrome that contributes significantly to long-term morbidity and reduced quality of life for ICU survivors and caregivers. Historically, research in this field has focused on pathological changes within the muscle itself, without much consideration for their in vivo physiological environment. Skeletal muscle has the widest range of oxygen metabolism of any organ, and regulation of oxygen supply with tissue demand is a fundamental requirement for locomotion and muscle function. During exercise, this process is exquisitely controlled and coordinated by the cardiovascular, respiratory, and autonomic systems, and also within the skeletal muscle microcirculation and mitochondria as the terminal site of oxygen exchange and utilization. This review highlights the potential contribution of the microcirculation and integrative cardiovascular physiology to the pathogenesis of ICU-AW. An overview of skeletal muscle microvascular structure and function is provided, as well as our understanding of microvascular dysfunction during the acute phase of critical illness; whether microvascular dysfunction persists after ICU discharge is currently not known. Molecular mechanisms that regulate crosstalk between endothelial cells and myocytes are discussed, including the role of the microcirculation in skeletal muscle atrophy, oxidative stress, and satellite cell biology. The concept of integrated control of oxygen delivery and utilization during exercise is introduced, with evidence of physiological dysfunction throughout the oxygen delivery pathway - from mouth to mitochondria - causing reduced exercise capacity in patients with chronic disease (e.g., heart failure, COPD). We suggest that objective and perceived weakness after critical illness represents a physiological failure of oxygen supply-demand matching - both globally throughout the body and locally within skeletal muscle. Lastly, we highlight the value of standardized cardiopulmonary exercise testing protocols for evaluating fitness in ICU survivors, and the application of near-infrared spectroscopy for directly measuring skeletal muscle oxygenation, representing potential advancements in ICU-AW research and rehabilitation.
Collapse
Affiliation(s)
- Asher A. Mendelson
- Section of Critical Care Medicine, Department of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Dustin Erickson
- Section of Critical Care Medicine, Department of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Rodrigo Villar
- Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, MB, Canada
| |
Collapse
|
15
|
Brobakken MF, Nygård M, Wang E. Physical Health Impairment and Exercise as Medicine in Severe Mental Disorders: A Narrative Review. SPORTS MEDICINE - OPEN 2022; 8:115. [PMID: 36107334 PMCID: PMC9478018 DOI: 10.1186/s40798-022-00490-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 07/17/2022] [Indexed: 01/20/2023]
Abstract
BACKGROUND Individuals with severe mental disorders (SMDs; schizophrenia spectrum disorders, bipolar disorder, and major depressive disorder) are not only suffering from their mental conditions; they also have an attenuated physical health, augmenting their overall critical condition. OBJECTIVES We review and critically appraise the evidence based on (1) key physiological factors relating to aerobic endurance and skeletal muscle strength; (2) implications for physical function and health; and (3) effects of training interventions with different intensities evaluated in individuals with SMDs. FINDINGS Reductions in aerobic endurance factors, peak oxygen uptake (VO2peak) and walking work efficiency, are paralleled by reductions in maximal skeletal muscle strength and power. In turn, the poor aerobic endurance and muscle strength lead to impaired physical function, increased risk of lifestyle-related diseases, and ultimately early death. Exercise has the potential to counteract the attenuated physical health in people with SMDs. While aerobic endurance training is shown to increase VO2peak due to plasticity of the oxygen transport system, strength training is documented to improve maximal muscle strength, power, and walking work efficiency as a result of adaptations in neuromuscular force developing factors. CONCLUSIONS In conclusion, improvements in these key determinants for physical health appear to be achievable in people with SMDs despite many being challenged by motivational difficulties with attending regular exercise and have beneficial implications for physical function during activities of daily living, lifestyle-related diseases, and early death.
Collapse
Affiliation(s)
- Mathias Forsberg Brobakken
- grid.411834.b0000 0004 0434 9525Faculty of Health and Social Sciences, Molde University College, Molde, Norway ,grid.52522.320000 0004 0627 3560Department of Psychosis and Rehabilitation, Psychiatry Clinic, St. Olavs University Hospital, Trondheim, Norway
| | - Mona Nygård
- grid.52522.320000 0004 0627 3560Department of Psychosis and Rehabilitation, Psychiatry Clinic, St. Olavs University Hospital, Trondheim, Norway ,grid.5947.f0000 0001 1516 2393Department of Mental Health, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway
| | - Eivind Wang
- grid.411834.b0000 0004 0434 9525Faculty of Health and Social Sciences, Molde University College, Molde, Norway ,grid.52522.320000 0004 0627 3560Department of Psychosis and Rehabilitation, Psychiatry Clinic, St. Olavs University Hospital, Trondheim, Norway
| |
Collapse
|
16
|
Kontro H, Bertagnolli C, Murias JM, MacInnis MJ. Impairment in maximal lactate steady state after carbon monoxide inhalation is related to training status. Exp Physiol 2022; 107:1265-1282. [PMID: 36029041 DOI: 10.1113/ep090642] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 08/17/2022] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? What is the effect of an elevated COHb concentration following carbon monoxide inhalation on the maximal lactate steady state (MLSS) in humans and is this effect dependent on aerobic fitness? What is the main finding and its importance? An elevated COHb concentration intensified physiological responses to exercise at the MLSS- including heart rate, ventilation, and peripheral fatigue-in all participants and reduced the MLSS (i.e., destabilized the blood lactate concentration) in trained but not untrained males and females. ABSTRACT This study investigated whether a lower effective [Hb], induced by carbon monoxide (CO) inhalation, reduces the peak oxygen uptake (V̇O2 peak) and the maximal lactate steady state (MLSS) and whether training status explains individual variation in these impairments. Healthy young participants completed two ramp incremental tests (n = 20 [10 female]) and two trials at MLSS (n = 16 [8 female]) following CO rebreathe tests and sham procedures (SHAM) in random orders. All fitness variables were normalized to fat-free mass (FFM) to account for sex-related differences in body composition, and males and females were matched for aerobic fitness. The V̇O2 peak (mean [SD]: -4.2 [3.7]%), peak power output (-3.3 [2.2]%), and respiratory compensation point (-6.3 [4.5]%) were reduced in CO compared with SHAM (P < 0.001 for all), but the gas exchange threshold (-3.3 [7.1]%) was not (P = 0.077). Decreases in V̇O2 peak (r = -0.45; P = 0.047) and peak power output (r = -0.49; P = 0.029) in CO were correlated with baseline aerobic fitness. Compared to SHAM, physiological and perceptual indicators of exercise-related stress were exacerbated by CO while cycling at MLSS. Notably, the mean blood lactate concentration ([La]) increased (i.e., Δ[La] > 1.0 mM) between 10 min (5.5 [1.4] mM) and 30 min (6.8 [1.3] mM; P = 0.026) in CO, with 9/16 participants classified as unstable. These unstable participants had a higher V̇O2 peak (66.2 [8.5] vs. 56.4 [8.8] mL·kg FFM-1 ·min-1 , P = 0.042) and V̇O2 at MLSS (55.8 vs. 44.3 mL·kg FFM-1 ·min-1 , P = 0.006) compared to the stable group. In conclusion, a reduced O2 -carrying capacity decreased maximal and submaximal exercise performance, with higher aerobic fitness associated with greater impairments in both. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Hilkka Kontro
- Faculty of Kinesiology, Human Performance Lab, University of Calgary, Canada
| | - Craig Bertagnolli
- Faculty of Kinesiology, Human Performance Lab, University of Calgary, Canada
| | - Juan M Murias
- Faculty of Kinesiology, Human Performance Lab, University of Calgary, Canada
| | - Martin J MacInnis
- Faculty of Kinesiology, Human Performance Lab, University of Calgary, Canada
| |
Collapse
|
17
|
Alvarez Villela M, Dunworth SA, Kraft BD, Harlan NP, Natoli MJ, Suliman HB, Moon RE. Effects of high-intensity interval training with hyperbaric oxygen. Front Physiol 2022; 13:963799. [PMID: 36060678 PMCID: PMC9437248 DOI: 10.3389/fphys.2022.963799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 07/27/2022] [Indexed: 11/29/2022] Open
Abstract
Hyperbaric Oxygen (HBO2) has been proposed as a pre-conditioning method to enhance exercise performance. Most prior studies testing this effect have been limited by inadequate methodologies. Its potential efficacy and mechanism of action remain unknown. We hypothesized that HBO2 could enhance aerobic capacity by inducing mitochondrial biogenesis via redox signaling in skeletal muscle. HBO2 was administered in combination with high-intensity interval training (HIIT), a potent redox stimulus known to induce mitochondrial biogenesis. Aerobic capacity was tested during acute hypobaric hypoxia seeking to shift the limiting site of whole body V̇O2 from convection to diffusion, more closely isolating any effect of improved oxidative capacity. Healthy volunteers were screened with sea-level (SL) V̇O2peak testing. Seventeen subjects were enrolled (10 men, 7 women, ages 26.5±1.3 years, BMI 24.6±0.6 kg m−2, V̇O2peak SL = 43.4±2.1). Each completed 6 HIIT sessions over 2 weeks randomized to breathing normobaric air, “HIIT+Air” (PiO2 = 0.21 ATM) or HBO2 (PiO2 = 1.4 ATM) during training, “HIIT+HBO2” group. Training workloads were individualized based on V̇O2peak SL test. Vastus Lateralis (VL) muscle biopsies were performed before and after HIIT in both groups. Baseline and post-training V̇O2peak tests were conducted in a hypobaric chamber at PiO2 = 0.12 ATM. HIIT significantly increased V̇O2peak in both groups: HIIT+HBO2 31.4±1.5 to 35.2±1.2 ml kg−1·min−1 and HIIT+Air 29.0±3.1 to 33.2±2.5 ml kg−1·min−1 (p = 0.005) without an additional effect of HBO2 (p = 0.9 for interaction of HIIT x HBO2). Subjects randomized to HIIT+HBO2 displayed higher skeletal muscle mRNA levels of PPARGC1A, a regulator of mitochondrial biogenesis, and HK2 and SLC2A4, regulators of glucose utilization and storage. All other tested markers of mitochondrial biogenesis showed no additional effect of HBO2 to HIIT. When combined with HIIT, short-term modest HBO2 (1.4 ATA) has does not increase whole-body V̇O2peak during acute hypobaric hypoxia. (ClinicalTrials.gov Identifier: NCT02356900; https://clinicaltrials.gov/ct2/show/NCT02356900).
Collapse
Affiliation(s)
- Miguel Alvarez Villela
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, NC, United States
| | - Sophia A. Dunworth
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, NC, United States
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, United States
| | - Bryan D. Kraft
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, NC, United States
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Duke University Medical Center, Durham, NC, United States
| | - Nicole P. Harlan
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, NC, United States
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Duke University Medical Center, Durham, NC, United States
| | - Michael J. Natoli
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, NC, United States
| | - Hagir B. Suliman
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, NC, United States
| | - Richard E. Moon
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, NC, United States
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, United States
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Duke University Medical Center, Durham, NC, United States
- *Correspondence: Richard E. Moon,
| |
Collapse
|
18
|
de França E, dos Santos RVT, Baptista LC, Da Silva MAR, Fukushima AR, Hirota VB, Martins RA, Caperuto EC. Potential Role of Chronic Physical Exercise as a Treatment in the Development of Vitiligo. Front Physiol 2022; 13:843784. [PMID: 35360245 PMCID: PMC8960951 DOI: 10.3389/fphys.2022.843784] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Accepted: 02/08/2022] [Indexed: 02/04/2023] Open
Abstract
Vitiligo is an autoimmune disease characterized by progressive skin depigmentation and the appearance of white patches throughout the body caused by significant apoptosis of epidermal melanocytes. Despite not causing any physical pain, vitiligo can originate several psychosocial disorders, drastically reducing patients' quality of life. Emerging evidence has shown that vitiligo is associated with several genetic polymorphisms related to auto-reactivity from the immune system to melanocytes. Melanocytes from vitiligo patients suffer from excess reactive oxygen species (ROS) produced by defective mitochondria besides a poor endogenous antioxidant system (EAS). This redox imbalance results in dramatic melanocyte oxidative stress (OS), causing significant damage in proteins, lipid membranes, and DNA. The damaged melanocytes secret damage-associated molecular pattern (DAMPs), inducing and increasing inflammatory gene expression response that ultimately leads to melanocytes apoptosis. Vitiligo severity has been also associated with increasing the prevalence and incidence of metabolic syndrome (MetS) or associated disorders such as insulin resistance and hypercholesterolemia. Thus, suggesting that in genetically predisposed individuals, the environmental context that triggers MetS (i.e., sedentary lifestyle) may also be an important trigger for the development and severity of vitiligo disease. This paper will discuss the relationship between the immune system and epidermal melanocytes and their interplay with the redox system. Based on state-of-the-art evidence from the vitiligo research, physical exercise (PE) immunology, and redox system literature, we will also propose chronic PE as a potential therapeutic strategy to treat and prevent vitiligo disease progression. We will present evidence that chronic PE can change the balance of inflammatory to an anti-inflammatory state, improve both EAS and the mitochondrial structure and function (resulting in the decrease of OS). Finally, we will highlight clinically relevant markers that can be analyzed in a new research avenue to test the potential applicability of chronic PE in vitiligo disease.
Collapse
Affiliation(s)
- Elias de França
- Human Movement Laboratory, São Judas University, São Paulo, Brazil
- Departamento de Biociências, Universidade Federal de São Paulo, São Paulo, Brazil
| | | | - Liliana C. Baptista
- Faculty of Sport, Research Centre in Physical Activity, Health and Leisure, University of Porto, Porto, Portugal
- Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, AL United States
- Targeted Exercise, Microbiome and Aging Laboratory, University of Alabama, Birmingham, AL United States
| | - Marco A. R. Da Silva
- Faculty of Sport Sciences and Physical Education, University of Coimbra, Coimbra, Portugal
- Department of Physical Education, Universidade da Amazônia, Belém, Brazil
| | - André R. Fukushima
- Centro Universitário das Américas – FAM, São Paulo, Brazil
- Faculdade de Ciências da Saúde – IGESP – FASIG, São Paulo, Brazil
| | | | - Raul A. Martins
- Faculty of Sport Sciences and Physical Education, University of Coimbra, Coimbra, Portugal
| | | |
Collapse
|
19
|
de Aguiar RA, Turnes T, Borszcz FK, Raimundo JAG, Caputo F. NIRS-derived muscle V̇O 2 kinetics after moderate running exercise in healthy males: reliability and associations with parameters of aerobic fitness. Exp Physiol 2022; 107:476-488. [PMID: 35244956 DOI: 10.1113/ep090105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 03/01/2022] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? In vivo muscle oxidative capacity has been evaluated through the mV̇O2 kinetics following single joint exercise using NIRS system. Here, we demonstrated its utility following running exercise. What is the main finding and its importance? We demonstrated that time constant of mV̇O2 kinetics in gastrocnemius following moderate running exercise presents good to excellent reliability. In addition, it was well correlated with parameters of aerobic fitness, such as maximal speed of the incremental test, ventilatory threshold and pulmonary V̇O2 on-kinetics. Therefore, NIRS-derived muscle oxidative capacity together with other physiological measurements may allow a concomitant local and systemic analysis of the components of the oxidative system. ABSTRACT NIRS-derived muscle oxygen uptake (mV̇O2 ) kinetics following single-joint exercise has been used to assess muscle oxidative capacity. However, little evidence is available on the use of this technique following whole-body exercises. Therefore, this study aimed to assess the reliability of the NIRS-derived mV̇O2 kinetics following running exercise and to investigate the relationship between the time constant of mV̇O2 off-kinetics (τmV̇O2 ) with parameters of aerobic fitness. After an incremental test to determine V̇O2 max, first (VT1 ) and second (VT2 ) ventilatory thresholds, and maximal speed (Smax), thirteen males (age = 21 ± 4 years; V̇O2 max = 55.9 ± 3.4 mlꞏkg-1ꞏmin-1) performed three sets (two in the first day and one on a subsequent day) of two repetitions of 6-min running exercise at 90%VT1 . The pulmonary V̇O2 on-kinetics (pV̇O2 ) and mV̇O2 off-kinetics in gastrocnemius were assessed. τmV̇O2 presented no systematic change and satisfactory reliability (SEM and ICC of 4.21 s and 0.49 for between transitions; and 2.65 s and 0.74 averaging τmV̇O2 within each time-set), with no difference (p > 0.3) between the within- (SEM = 2.92 s) and between-day variability (SEM = 2.78 s and 2.19 s between first vs. third set, and second vs. third set, respectively). τmV̇O2 (28.5 ± 4.17 s) correlated significantly (p < 0.05) with Smax (r = -0.66), VT1 (r = -0.64) and time constant of the pV̇O2 on-kinetics (r = 0.69). These findings indicate that NIRS-derived mV̇O2 kinetics in the gastrocnemius following moderate running exercise is a useful and reliable method to assess muscle oxidative capacity. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Rafael A de Aguiar
- Human Performance Research Group, College of Health and Sport Science, Santa Catarina State University, Florianópolis, Brazil
| | - Tiago Turnes
- Human Performance Research Group, College of Health and Sport Science, Santa Catarina State University, Florianópolis, Brazil.,Physical Effort Laboratory, Sports Centre, Federal University of Santa Catarina, Florianópolis, Brazil
| | - Fernando K Borszcz
- Physical Effort Laboratory, Sports Centre, Federal University of Santa Catarina, Florianópolis, Brazil
| | - João A G Raimundo
- Human Performance Research Group, College of Health and Sport Science, Santa Catarina State University, Florianópolis, Brazil
| | - Fabrizio Caputo
- Human Performance Research Group, College of Health and Sport Science, Santa Catarina State University, Florianópolis, Brazil
| |
Collapse
|
20
|
Lewis MT, Levitsky Y, Bazil JN, Wiseman RW. Measuring Mitochondrial Function: From Organelle to Organism. Methods Mol Biol 2022; 2497:141-172. [PMID: 35771441 DOI: 10.1007/978-1-0716-2309-1_10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Mitochondrial energy production is crucial for normal daily activities and maintenance of life. Herein, the logic and execution of two main classes of measurements are outlined to delineate mitochondrial function: ATP production and oxygen consumption. Aerobic ATP production is quantified by phosphorus magnetic resonance spectroscopy (31PMRS) in vivo in both human subjects and animal models using the same protocols and maintaining the same primary assumptions. Mitochondrial oxygen consumption is quantified by oxygen polarography and applied in isolated mitochondria, cultured cells, and permeabilized fibers derived from human or animal tissue biopsies. Traditionally, mitochondrial functional measures focus on maximal oxidative capacity-a flux rate that is rarely, if ever, observed outside of experimental conditions. Perhaps more physiologically relevant, both measurement classes herein focus on one principal design paradigm; submaximal mitochondrial fluxes generated by graded levels of ADP to map the function for ADP sensitivity. We propose this function defines the bioenergetic role that mitochondria fill within the myoplasm to sense and match ATP demands. Any deficit in this vital role for ATP homeostasis leads to symptoms often seen in cardiovascular and cardiopulmonary diseases, diabetes, and metabolic syndrome.
Collapse
Affiliation(s)
- Matthew T Lewis
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education, and Clinical Center, VA Medical Center, Salt Lake City, UT, USA
| | - Yan Levitsky
- Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - Jason N Bazil
- Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - Robert W Wiseman
- Department of Physiology, Michigan State University, East Lansing, MI, USA. .,Department of Radiology, Michigan State University, East Lansing, MI, USA.
| |
Collapse
|
21
|
Salvadego D, Grassi B, Keramidas ME, Eiken O, McDonnell AC, Mekjavic IB. Heterogeneity of human adaptations to bed rest and hypoxia: a retrospective analysis within the skeletal muscle oxidative function. Am J Physiol Regul Integr Comp Physiol 2021; 321:R813-R822. [PMID: 34585615 DOI: 10.1152/ajpregu.00053.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This retrospective study was designed to analyze the interindividual variability in the responses of different variables characterizing the skeletal muscle oxidative function to normoxic (N-BR) and hypoxic (H-BR) bed rests and to a hypoxic ambulatory confinement (H-AMB) of 10 and 21 days. We also assessed whether and how the addition of hypoxia to bed rest might influence the heterogeneity of the responses. In vivo measurements of O2 uptake and muscle fractional O2 extraction were carried out during an incremental one-leg knee-extension exercise. Mitochondrial respiration was assessed in permeabilized muscle fibers. A total of 17 subjects were included in this analysis. This analysis revealed a similar variability among subjects in the alterations induced by N-BR and H-BR both in peak O2 uptake (SD: 4.1% and 3.3% after 10 days; 4.5% and 8.1% after 21 days, respectively) and peak muscle fractional O2 extraction (SD: 5.9% and 7.3% after 10 days; 6.5% and 7.3% after 21 days), independently from the duration of the exposure. The individual changes measured in these variables were significantly related (r = 0.66, P = 0.004 after N-BR; r = 0.61, P = 0.009 after H-BR). Mitochondrial respiration showed a large variability of response after both N-BR (SD: 25.0% and 15.7% after 10 and 21 days) and H-BR (SD: 13.0% and 19.8% after 10 and 21 days); no correlation was found between N-BR and H-BR changes. When added to bed rest, hypoxia altered the individual adaptations within the mitochondria but not those intrinsic to the muscle oxidative function in vivo, both after the short- and medium-term exposures.
Collapse
Affiliation(s)
- Desy Salvadego
- Department of Automation, Biocybernetics and Robotics, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Bruno Grassi
- Department of Medicine, University of Udine, Udine, Italy
| | - Michail E Keramidas
- Department of Environmental Physiology, Swedish Aerospace Physiology Centre, Royal Institute of Technology, Stockholm, Sweden
| | - Ola Eiken
- Department of Environmental Physiology, Swedish Aerospace Physiology Centre, Royal Institute of Technology, Stockholm, Sweden
| | - Adam C McDonnell
- Department of Automation, Biocybernetics and Robotics, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Igor B Mekjavic
- Department of Automation, Biocybernetics and Robotics, Jožef Stefan Institute, Ljubljana, Slovenia.,Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| |
Collapse
|
22
|
Marchant ED, Marchant ND, Hyldahl RD, Gifford JR, Smith MW, Hancock CR. Skeletal Muscle Mitochondrial Function after a 100-km Ultramarathon: A Case Study in Monozygotic Twins. Med Sci Sports Exerc 2021; 53:2363-2373. [PMID: 34107508 DOI: 10.1249/mss.0000000000002715] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE Very little research has investigated the effects of ultraendurance exercise on the bioenergetic status of muscle. The primary objective of this case study was to characterize the changes that occur in skeletal muscle mitochondria in response to a 100-km ultramarathon in monozygotic twins. A second objective was to determine whether mitochondrial function is altered by consuming a periodized low-carbohydrate, high-fat diet during training compared with a high-carbohydrate diet. METHODS One pair of male monozygotic twins ran 100 km on treadmills after 4 wk of training on either a high-carbohydrate or periodized low-carbohydrate, high-fat diet. Muscle biopsies were collected 4 wk before the run, as well as 4 and 52 h postrun. Blood draws were also performed immediately before as well as 4 and 52 h after the run. RESULTS Four hours postrun, respiratory capacity, citrate synthase activity, and mitochondrial complex protein content were decreased. Two days later, both twins showed signs of rapid recovery in several of these measures. Furthermore, blood levels of creatine phosphokinase, C-reactive protein, and aspartate transaminase were elevated 4 h after the run but partially recovered 2 d later. CONCLUSION Although there were some differences between the twins, the primary finding is that there is significant mitochondrial impairment induced by running 100 km, which rapidly recovers within 2 d. These results provide ample rationale for future investigations of the effects of ultraendurance activity on mitochondrial function.
Collapse
Affiliation(s)
- Erik D Marchant
- Nutrition, Dietetics and Food Science, Brigham Young University, Provo, UT
| | - Nathan D Marchant
- Nutrition, Dietetics and Food Science, Brigham Young University, Provo, UT
| | | | | | - Michael W Smith
- Nutrition, Dietetics and Food Science, Brigham Young University, Provo, UT
| | - Chad R Hancock
- Nutrition, Dietetics and Food Science, Brigham Young University, Provo, UT
| |
Collapse
|
23
|
van der Zwaard S, Brocherie F, Jaspers RT. Under the Hood: Skeletal Muscle Determinants of Endurance Performance. Front Sports Act Living 2021; 3:719434. [PMID: 34423293 PMCID: PMC8371266 DOI: 10.3389/fspor.2021.719434] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 07/05/2021] [Indexed: 11/21/2022] Open
Abstract
In the past decades, researchers have extensively studied (elite) athletes' physiological responses to understand how to maximize their endurance performance. In endurance sports, whole-body measurements such as the maximal oxygen consumption, lactate threshold, and efficiency/economy play a key role in performance. Although these determinants are known to interact, it has also been demonstrated that athletes rarely excel in all three. The leading question is how athletes reach exceptional values in one or all of these determinants to optimize their endurance performance, and how such performance can be explained by (combinations of) underlying physiological determinants. In this review, we advance on Joyner and Coyle's conceptual framework of endurance performance, by integrating a meta-analysis of the interrelationships, and corresponding effect sizes between endurance performance and its key physiological determinants at the macroscopic (whole-body) and the microscopic level (muscle tissue, i.e., muscle fiber oxidative capacity, oxygen supply, muscle fiber size, and fiber type). Moreover, we discuss how these physiological determinants can be improved by training and what potential physiological challenges endurance athletes may face when trying to maximize their performance. This review highlights that integrative assessment of skeletal muscle determinants points toward efficient type-I fibers with a high mitochondrial oxidative capacity and strongly encourages well-adjusted capillarization and myoglobin concentrations to accommodate the required oxygen flux during endurance performance, especially in large muscle fibers. Optimisation of endurance performance requires careful design of training interventions that fine tune modulation of exercise intensity, frequency and duration, and particularly periodisation with respect to the skeletal muscle determinants.
Collapse
Affiliation(s)
- Stephan van der Zwaard
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, Netherlands
- Laboratory for Myology, Department of Human Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, Netherlands
- Leiden Institute of Advanced Computer Science, Leiden University, Leiden, Netherlands
| | - Franck Brocherie
- Laboratory Sport, Expertise and Performance (EA 7370), French Institute of Sport (INSEP), Paris, France
| | - Richard T. Jaspers
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, Netherlands
- Laboratory for Myology, Department of Human Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, Netherlands
| |
Collapse
|
24
|
Objective assessment of metabolism and guidance of ICU rehabilitation with cardiopulmonary exercise testing. Curr Opin Crit Care 2021; 27:390-398. [PMID: 33973897 DOI: 10.1097/mcc.0000000000000843] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW Addressing the reduced quality of life that affects ICU survivors is the most pressing challenge in critical care medicine. In order to meet this challenge, we must translate lessons learnt from assessing and training athletes to the clinical population, utilizing measurable and targeted parameters obtained during cardiopulmonary exercise testing (CPET). RECENT FINDINGS Critical illness survivors demonstrate a persistent reduction in their physical and metabolic function. This manifests in reduced aerobic exercise capacity and metabolic inflexibility. CPET-guided targeted metabolic conditioning has proved beneficial in several clinical populations, including those undergoing high-risk surgery, and could be successfully applied to the rehabilitation of ICU survivors. SUMMARY CPET shows great promise in the guidance of rehabilitation in functionally limited ICU survivors. Parallels in the physiological response to exercise in athletes and clinical populations with the stress and consequences of critical illness must be investigated and ultimately applied to the burgeoning population of ICU survivors in order to treat the consequences of survival from critical illness.
Collapse
|
25
|
Bostad W, Valentino SE, McCarthy DG, Richards DL, MacInnis MJ, MacDonald MJ, Gibala MJ. Twelve weeks of sprint interval training increases peak cardiac output in previously untrained individuals. Eur J Appl Physiol 2021; 121:2449-2458. [PMID: 34014402 DOI: 10.1007/s00421-021-04714-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 05/06/2021] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Sprint interval training (SIT), characterized by brief bouts of 'supramaximal' exercise interspersed with recovery periods, increases peak oxygen uptake ([Formula: see text]) despite a low total exercise volume. Per the Fick principle, increased [Formula: see text] is attributable to increased peak cardiac output ([Formula: see text]) and/or peak arterio-venous oxygen difference (a-vO2diff). There are limited and equivocal data regarding the physiological basis for SIT-induced increases in [Formula: see text], with most studies lasting ≤ 6 weeks. PURPOSE To determine the effect of 12 weeks of SIT on [Formula: see text], measured using inert gas rebreathing, and the relationship between changes in [Formula: see text] and [Formula: see text]. METHODS 15 healthy untrained adults [6 males, 9 females; 21 ± 2 y (mean ± SD)] performed 28 ± 3 training sessions. Each session involved a 2-min warm-up at 50 W, 3 × 20-s 'all-out' cycling bouts (581 ± 221 W) interspersed with 2-min of recovery, and a 3-min cool-down at 50 W. RESULTS Measurements performed before and after training showed that 12 weeks of SIT increased [Formula: see text] (17.0 ± 3.7 vs 18.1 ± 4.6 L/min, p = 0.01, partial η2 = 0.28) and [Formula: see text] (2.63 ± 0.78 vs 3.18 ± 1.1 L/min, p < 0.01, partial η2 = 0.58). The changes in these two variables were correlated (r2 = 0.46, p < 0.01). Calculated peak a-vO2diff also increased after training (154 ± 22 vs 174 ± 23 ml O2/L; p < 0.01) and was correlated with the change in [Formula: see text] (r2 = 0.33, p = 0.03). Exploratory analyses revealed an interaction (p < 0.01) such that [Formula: see text] increased in male (+ 10%, p < 0.01) but not female participants (+ 0.6%, p = 0.96), suggesting potential sex-specific differences. CONCLUSION Twelve weeks of SIT increased [Formula: see text] by 6% in previously untrained participants and the change was correlated with the larger 21% increase in [Formula: see text].
Collapse
Affiliation(s)
- William Bostad
- Department of Kinesiology, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Sydney E Valentino
- Department of Kinesiology, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Devin G McCarthy
- Department of Kinesiology, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | | | | | - Maureen J MacDonald
- Department of Kinesiology, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Martin J Gibala
- Department of Kinesiology, McMaster University, Hamilton, ON, L8S 4K1, Canada.
| |
Collapse
|
26
|
Zamani P, Proto EA, Wilson N, Fazelinia H, Ding H, Spruce LA, Davila A, Hanff TC, Mazurek JA, Prenner SB, Desjardins B, Margulies KB, Kelly DP, Arany Z, Doulias PT, Elrod JW, Allen ME, McCormack SE, Schur GM, D'Aquilla K, Kumar D, Thakuri D, Prabhakaran K, Langham MC, Poole DC, Seeholzer SH, Reddy R, Ischiropoulos H, Chirinos JA. Multimodality assessment of heart failure with preserved ejection fraction skeletal muscle reveals differences in the machinery of energy fuel metabolism. ESC Heart Fail 2021; 8:2698-2712. [PMID: 33991175 PMCID: PMC8318475 DOI: 10.1002/ehf2.13329] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 02/25/2021] [Accepted: 03/12/2021] [Indexed: 02/06/2023] Open
Abstract
AIMS Skeletal muscle (SkM) abnormalities may impact exercise capacity in patients with heart failure with preserved ejection fraction (HFpEF). We sought to quantify differences in SkM oxidative phosphorylation capacity (OxPhos), fibre composition, and the SkM proteome between HFpEF, hypertensive (HTN), and healthy participants. METHODS AND RESULTS Fifty-nine subjects (20 healthy, 19 HTN, and 20 HFpEF) performed a maximal-effort cardiopulmonary exercise test to define peak oxygen consumption (VO2, peak ), ventilatory threshold (VT), and VO2 efficiency (ratio of total work performed to O2 consumed). SkM OxPhos was assessed using Creatine Chemical-Exchange Saturation Transfer (CrCEST, n = 51), which quantifies unphosphorylated Cr, before and after plantar flexion exercise. The half-time of Cr recovery (t1/2, Cr ) was taken as a metric of in vivo SkM OxPhos. In a subset of subjects (healthy = 13, HTN = 9, and HFpEF = 12), percutaneous biopsy of the vastus lateralis was performed for myofibre typing, mitochondrial morphology, and proteomic and phosphoproteomic analysis. HFpEF subjects demonstrated lower VO2,peak , VT, and VO2 efficiency than either control group (all P < 0.05). The t1/2, Cr was significantly longer in HFpEF (P = 0.005), indicative of impaired SkM OxPhos, and correlated with cycle ergometry exercise parameters. HFpEF SkM contained fewer Type I myofibres (P = 0.003). Proteomic analyses demonstrated (a) reduced levels of proteins related to OxPhos that correlated with exercise capacity and (b) reduced ERK signalling in HFpEF. CONCLUSIONS Heart failure with preserved ejection fraction patients demonstrate impaired functional capacity and SkM OxPhos. Reductions in the proportions of Type I myofibres, proteins required for OxPhos, and altered phosphorylation signalling in the SkM may contribute to exercise intolerance in HFpEF.
Collapse
Affiliation(s)
- Payman Zamani
- Penn Cardiovascular Institute, Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Elizabeth A Proto
- Penn Cardiovascular Institute, Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Neil Wilson
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Hossein Fazelinia
- Proteomics Core, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Hua Ding
- Proteomics Core, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Lynn A Spruce
- Proteomics Core, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Antonio Davila
- Penn Acute Care Research Collaboration, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Thomas C Hanff
- Penn Cardiovascular Institute, Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Jeremy A Mazurek
- Penn Cardiovascular Institute, Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Stuart B Prenner
- Penn Cardiovascular Institute, Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Benoit Desjardins
- Cardiovascular Imaging Section, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Kenneth B Margulies
- Penn Cardiovascular Institute, Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Daniel P Kelly
- Penn Cardiovascular Institute, Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Zoltan Arany
- Penn Cardiovascular Institute, Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | | | - John W Elrod
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Mitchell E Allen
- Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA, USA
| | - Shana E McCormack
- Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | | | - Kevin D'Aquilla
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Dushyant Kumar
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Deepa Thakuri
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Karthik Prabhakaran
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael C Langham
- Laboratory for Structural, Physiologic and Functional Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David C Poole
- Departments of Kinesiology, Anatomy, and Physiology, Kansas State University, Manhattan, KS, USA
| | - Steven H Seeholzer
- Proteomics Core, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Ravinder Reddy
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Harry Ischiropoulos
- Children's Hospital of Philadelphia Research Institute, Philadelphia, PA, USA
| | - Julio A Chirinos
- Penn Cardiovascular Institute, Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA, 19104, USA
| |
Collapse
|
27
|
Lifelong Endurance Exercise as a Countermeasure Against Age-Related [Formula: see text] Decline: Physiological Overview and Insights from Masters Athletes. Sports Med 2021; 50:703-716. [PMID: 31873927 DOI: 10.1007/s40279-019-01252-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Maximum oxygen consumption ([Formula: see text]) is not only an indicator of endurance performance, but also a strong predictor of cardiovascular disease and mortality. This physiological parameter is known to decrease with aging. In turn, physical exercise might attenuate the rate of aging-related decline in [Formula: see text], which in light of the global population aging is of major clinical relevance, especially at advanced ages. In this narrative review, we summarize the evidence available from masters athletes about the role of lifelong endurance exercise on aging-related [Formula: see text] decline, with examples of the highest [Formula: see text] values reported in the scientific literature for athletes across different ages (e.g., 35 ml·kg-1·min-1 in a centenarian cyclist). These data suggest that a linear decrease in [Formula: see text] might be possible if physical exercise loads are kept consistently high through the entire life span, with [Formula: see text] values remaining higher than those of the general population across all ages. We also summarize the main physiological changes that occur with inactive aging at different system levels-pulmonary and cardiovascular function, blood O2 carrying capacity, skeletal muscle capillary density and oxidative capacity-and negatively influence [Formula: see text], and review how lifelong exercise can attenuate or even prevent most-but apparently not all (e.g., maximum heart rate decline)-of them. In summary, although aging seems to be invariably associated with a progressive decline in [Formula: see text], maintaining high levels of physical exercise along the life span slows the multi-systemic deterioration that is commonly observed in inactive individuals, thereby attenuating age-related [Formula: see text] decline.
Collapse
|
28
|
Pignanelli C, Christiansen D, Burr JF. Blood flow restriction training and the high-performance athlete: science to application. J Appl Physiol (1985) 2021; 130:1163-1170. [PMID: 33600282 DOI: 10.1152/japplphysiol.00982.2020] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The manipulation of blood flow in conjunction with skeletal muscle contraction has greatly informed the physiological understanding of muscle fatigue, blood pressure reflexes, and metabolism in humans. Recent interest in using intentional blood flow restriction (BFR) has focused on elucidating how exercise during periods of reduced blood flow affects typical training adaptations. A large initial appeal for BFR training was driven by studies demonstrating rapid increases in muscle size, strength, and endurance capacity, even when notably low intensities and resistances, which would typically be incapable of stimulating change in healthy populations, were used. The incorporation of BFR exercise into the training of strength- and endurance-trained athletes has recently been shown to provide additive training effects that augment skeletal muscle and cardiovascular adaptations. Recent observations suggest BFR exercise alters acute physiological stressors such as local muscle oxygen availability and vascular shear stress, which may lead to adaptations that are not easily attained with conventional training. This review explores these concepts and summarizes both the evidence base and knowledge gaps regarding the application of BFR training for athletes.
Collapse
Affiliation(s)
- Christopher Pignanelli
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Danny Christiansen
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - Jamie F Burr
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| |
Collapse
|
29
|
Jacobs RA, Lundby C. Contextualizing the biological relevance of standardized high-resolution respirometry to assess mitochondrial function in permeabilized human skeletal muscle. Acta Physiol (Oxf) 2021; 231:e13625. [PMID: 33570804 PMCID: PMC8047922 DOI: 10.1111/apha.13625] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 12/16/2022]
Abstract
Aim This study sought to provide a statistically robust reference for measures of mitochondrial function from standardized high‐resolution respirometry with permeabilized human skeletal muscle (ex vivo), compare analogous values obtained via indirect calorimetry, arterial‐venous O2 differences and 31P magnetic resonance spectroscopy (in vivo) and attempt to resolve differences across complementary methodologies as necessary. Methods Data derived from 831 study participants across research published throughout March 2009 to November 2019 were amassed to examine the biological relevance of ex vivo assessments under standard conditions, ie physiological temperatures of 37°C and respiratory chamber oxygen concentrations of ~250 to 500 μmol/L. Results Standard ex vivo‐derived measures are lower (Z ≥ 3.01, P ≤ .0258) en masse than corresponding in vivo‐derived values. Correcting respiratory values to account for mitochondrial temperatures 10°C higher than skeletal muscle temperatures at maximal exercise (~50°C): (i) transforms data to resemble (Z ≤ 0.8, P > .9999) analogous yet context‐specific in vivo measures, eg data collected during maximal 1‐leg knee extension exercise; and (ii) supports the position that maximal skeletal muscle respiratory rates exceed (Z ≥ 13.2, P < .0001) those achieved during maximal whole‐body exercise, e.g. maximal cycling efforts. Conclusion This study outlines and demonstrates necessary considerations when actualizing the biological relevance of human skeletal muscle respiratory control, metabolic flexibility and bioenergetics from standard ex vivo‐derived assessments using permeabilized human muscle. These findings detail how cross‐procedural comparisons of human skeletal muscle mitochondrial function may be collectively scrutinized in their relationship to human health and lifespan.
Collapse
Affiliation(s)
- Robert A. Jacobs
- Department of Human Physiology & Nutrition University of Colorado Colorado Springs (UCCS) Colorado Springs CO USA
| | - Carsten Lundby
- Innland University of Applied Sciences Lillehammer Norway
| |
Collapse
|
30
|
Inglis EC, Iannetta D, Murias JM. Association between [Formula: see text]O 2 kinetics and [Formula: see text]O 2max in groups differing in fitness status. Eur J Appl Physiol 2021; 121:1921-1931. [PMID: 33730210 DOI: 10.1007/s00421-021-04623-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 02/05/2021] [Indexed: 11/25/2022]
Abstract
PURPOSE This study evaluated (i) the relationship between oxygen uptake ([Formula: see text]O2) kinetics and maximal [Formula: see text]O2 ([Formula: see text]O2max) within groups differing in fitness status, and (ii) the adjustment of [Formula: see text]O2 kinetics compared to that of central [cardiac output (Q̇), heart rate (HR)] and peripheral (deoxyhemoglobin over [Formula: see text]O2 ratio ([HHb]/[Formula: see text]O2)] O2 delivery, during step-transitions to moderate-intensity exercise. METHODS Thirty-six young healthy male participants (18 untrained; 18 trained) performed a ramp-incremental test to exhaustion and 3 step-transitions to moderate-intensity exercise. Q̇ and HR kinetics were measured in 18 participants (9 untrained; 9 trained). RESULTS No significant correlation between τ̇[Formula: see text]O2 and [Formula: see text]O2max was found in trained participants (r = 0.29; p > 0.05) whereas a significant negative correlation was found in untrained (r = - 0.58; p < 0.05) and all participants (r = - 0.82; p < 0.05). τQ̇ (18.8 ± 5.5 s) and τHR (20.1 ± 6.2 s) were significantly greater than τ[Formula: see text]O2 (13.9 ± 2.7 s) for trained (p < 0.05). No differences were found between τQ̇ (22.8 ± 8.45 s), τHR (21.2 ± 8.3 s) and τ[Formula: see text]O2 (28.9 ± 5.7 s) for untrained (p > 0.05). τQ̇ demonstrated a significant strong positive correlation with τHR in trained (r = 0.76; p < 0.05) but not untrained (r = 0.61; p > 0.05). A significant overshoot in the [HHb]/[Formula: see text]O2 ratio was found in the untrained groups (p < 0.05) but not in the trained groups (p > 0.05) CONCLUSION: The results indicated that when comparing participants of different fitness status (i) there is a point at which greater V̇O2max values are not accompanied by faster [Formula: see text]O2 kinetics; (ii) central delivery of O2 does not seem to limit the kinetics of [Formula: see text]O2; and (iii) O2 delivery within the active tissues might contribute to the slower [Formula: see text]O2 kinetics response in untrained participants.
Collapse
Affiliation(s)
- Erin Calaine Inglis
- Faculty of Kinesiology, University of Calgary, KNB 434, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada
| | - Danilo Iannetta
- Faculty of Kinesiology, University of Calgary, KNB 434, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada
| | - Juan M Murias
- Faculty of Kinesiology, University of Calgary, KNB 434, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada.
| |
Collapse
|
31
|
Bartlett MF, Fitzgerald LF, Kent JA. Rates of oxidative ATP synthesis are not augmented beyond the pH threshold in human vastus lateralis muscles during a stepwise contraction protocol. J Physiol 2021; 599:1997-2013. [PMID: 33576028 DOI: 10.1113/jp280851] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 02/05/2021] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The oxygen cost of high-intensity exercise at power outputs above an individual's lactate threshold (LT) is greater than would be predicted by the linear oxygen consumption-power relationship observed below the LT. However, whether these augmentations are caused by an increased ATP cost of force generation (ATPCOST ) or an increased oxygen cost of ATP synthesis is unclear. We used 31 P-MRS to measure changes in cytosolic [ADP] (intramyocellular marker of oxidative metabolism), oxidative ATP synthesis (ATPOX ) and ATPCOST during a 6-stage, stepwise knee extension protocol. ATPCOST was unchanged across stages. The relationship between [ADP] and muscle power output was augmented at workloads above the pH threshold (pHT ; proxy for LT), whereas increases in ATPOX were attenuated. These results suggest the greater oxygen cost of contractions at workloads beyond the pHT is not caused by mechanisms that increase ATPCOST , but rather mechanisms that alter intrinsic mitochondrial function or capacity. ABSTRACT Increases in skeletal muscle metabolism and oxygen consumption are linearly related to muscle power output for workloads below the lactate threshold (LT), but are augmented (i.e. greater rate of increase relative to workload) thereafter. Presently, it is unclear whether these metabolic augmentations are caused by increases in the ATP cost of force generation (ATPCOST ) or changes in the efficiency of mitochondrial oxygen consumption and oxidative ATP synthesis (ATPOX ). To partition these two hypotheses in vivo, we used 31 P-MRS to calculate slopes relating step-changes in muscle work to concurrent changes in cytosolic phosphates and ATPOX before and after the pH threshold (pHT ; used here as a proxy for LT) within the vastus lateralis muscle of eight young adults during a stepwise knee extension test. Changes in muscle phosphates and ATPOX were linearly related to workload below the pHT . However, slopes above the pHT were greater for muscle phosphates (P < 0.05) and lower for ATPOX (P < 0.05) than were the slopes observed below the pHT . The maximal capacity for ATPOX ( V ̇ max ) and ADP-specific ATPOX also declined beyond the pHT (P < 0.05), whereas ATPCOST was unchanged (P = 0.10). These results oppose the hypothesis that high-intensity contractions increase ATPCOST and suggest that greater oxidative metabolism at workloads beyond the pHT is caused by mechanisms that affect intrinsic mitochondrial function or capacity, such as alterations in substrate selection or electron entry into the electron transport chain, temperature-mediated changes in mitochondrial permeability to protons, or stimulation of mitochondrial uncoupling by reactive oxygen species generation.
Collapse
Affiliation(s)
- Miles F Bartlett
- Muscle Physiology Laboratory, Department of Kinesiology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Liam F Fitzgerald
- Muscle Physiology Laboratory, Department of Kinesiology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Jane A Kent
- Muscle Physiology Laboratory, Department of Kinesiology, University of Massachusetts, Amherst, MA, 01003, USA
| |
Collapse
|
32
|
Gifford JR, Collins J. Critical Speed throughout Aging: Insight into the World Masters Championships. Med Sci Sports Exerc 2021; 53:524-533. [PMID: 33560767 DOI: 10.1249/mss.0000000000002501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
PURPOSE This study aimed to determine how the speed-distance relationship, described by critical speed (CS) and distance prime (D'), is altered with aging. METHODS Official race data from the past eight World Masters Athletics Indoor Track and Field World Championships were used for this study. CS and D' were calculated for female and male athletes (35-90 yr of age) who registered times for the 800-, 1500-, and 3000-m runs during a single championship to determine the relationship between age and CS and D'. Twenty-six athletes completed sufficient races in multiple championships to retrospectively assess the change in CS and D' over time. RESULTS Cross-sectional data indicated that CS continuously decreases after age 35 yr in a curvilinear manner with advancing age (R2 = 0.73, P < 0.001, n = 187), with even greater decreases in CS occurring after ~70 yr of age. D' also changed in a curvilinear manner with age (R2 = 0.45, P < 0.001, n = 103), such that decreases were observed between 35 and 70 yr, followed by an increase in D' thereafter. Retrospective, longitudinal data, with an average follow-up of 6.38 ± 1.73 yr, support these findings, indicating that the annual decrease in CS grows with advancing age (e.g., ~1% vs ~3% annual decrease in CS at age 55 vs 80 yr, respectively) and that D' shifts from an annual decrease (e.g., ~2.5% annual decrease at 55 yr) to an annual increase (e.g., ~2.5% annual increase at 80 yr) around 70 yr of age. Importantly, the relationship between CS and race pace was unaffected by age, supporting the relevance of CS throughout aging. CONCLUSION Even among world-class athletes, CS decreases and D' changes with aging. These adaptations may contribute to the diminished exercise ability associated with aging.
Collapse
Affiliation(s)
| | - Jessica Collins
- Department of Exercise Sciences, Brigham Young University, Provo, UT
| |
Collapse
|
33
|
Skattebo Ø, Calbet JAL, Rud B, Capelli C, Hallén J. Contribution of oxygen extraction fraction to maximal oxygen uptake in healthy young men. Acta Physiol (Oxf) 2020; 230:e13486. [PMID: 32365270 PMCID: PMC7540168 DOI: 10.1111/apha.13486] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 04/22/2020] [Accepted: 04/23/2020] [Indexed: 12/16/2022]
Abstract
We analysed the importance of systemic and peripheral arteriovenous O2 difference (
a-v¯O2 difference and a‐vfO2 difference, respectively) and O2 extraction fraction for maximal oxygen uptake (
V˙O2max). Fick law of diffusion and the Piiper and Scheid model were applied to investigate whether diffusion versus perfusion limitations vary with
V˙O2max. Articles (n = 17) publishing individual data (n = 154) on
V˙O2max, maximal cardiac output (
Q˙max; indicator‐dilution or the Fick method),
a-v¯O2 difference (catheters or the Fick equation) and systemic O2 extraction fraction were identified. For the peripheral responses, group‐mean data (articles: n = 27; subjects: n = 234) on leg blood flow (LBF; thermodilution), a‐vfO2 difference and O2 extraction fraction (arterial and femoral venous catheters) were obtained.
Q˙max and two‐LBF increased linearly by 4.9‐6.0 L · min–1 per 1 L · min–1 increase in
V˙O2max (R2 = .73 and R2 = .67, respectively; both P < .001). The
a-v¯O2 difference increased from 118‐168 mL · L–1 from a
V˙O2max of 2‐4.5 L · min–1 followed by a reduction (second‐order polynomial: R2 = .27). After accounting for a hypoxemia‐induced decrease in arterial O2 content with increasing
V˙O2max (R2 = .17; P < .001), systemic O2 extraction fraction increased up to ~90% (
V˙O2max: 4.5 L · min–1) with no further change (exponential decay model: R2 = .42). Likewise, leg O2 extraction fraction increased with
V˙O2max to approach a maximal value of ~90‐95% (R2 = .83). Muscle O2 diffusing capacity and the equilibration index Y increased linearly with
V˙O2max (R2 = .77 and R2 = .31, respectively; both P < .01), reflecting decreasing O2 diffusional limitations and accentuating O2 delivery limitations. In conclusion, although O2 delivery is the main limiting factor to
V˙O2max, enhanced O2 extraction fraction (≥90%) contributes to the remarkably high
V˙O2max in endurance‐trained individuals.
Collapse
Affiliation(s)
- Øyvind Skattebo
- Department of Physical Performance Norwegian School of Sport Sciences Oslo Norway
| | - Jose A. L. Calbet
- Department of Physical Performance Norwegian School of Sport Sciences Oslo Norway
- Department of Physical Education and Research Institute of Biomedical and Health Sciences (IUIBS) University of Las Palmas de Gran Canaria Gran Canaria Spain
| | - Bjarne Rud
- Department of Physical Performance Norwegian School of Sport Sciences Oslo Norway
| | - Carlo Capelli
- Department of Physical Performance Norwegian School of Sport Sciences Oslo Norway
- Department of Neurosciences, Biomedicine and Movement Sciences University of Verona Verona Italy
| | - Jostein Hallén
- Department of Physical Performance Norwegian School of Sport Sciences Oslo Norway
| |
Collapse
|
34
|
Brobakken MF, Nygård M, Güzey IC, Morken G, Reitan SK, Heggelund J, Vedul-Kjelsaas E, Wang E. One-year aerobic interval training in outpatients with schizophrenia: A randomized controlled trial. Scand J Med Sci Sports 2020; 30:2420-2436. [PMID: 33108030 DOI: 10.1111/sms.13808] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 08/03/2020] [Accepted: 08/11/2020] [Indexed: 12/25/2022]
Abstract
Although aerobic interval training (AIT) is recognized to attenuate the risk of cardiovascular disease (CVD) and premature mortality, it appears that it rarely arrives at patients' doorsteps. Thus, this study investigated 1-year effects and feasibility of AIT delivered with adherence support in collaborative care of outpatients with schizophrenia. Forty-eight outpatients (28 men, 35 [31-38] (mean [95% confidence intervals]) years; 20 women, 36 [30-41] years) with schizophrenia spectrum disorders (ICD-10) were randomized to either a collaborative care group provided with municipal transportation service and training supervision (walking/running 4 × 4 minutes at ~90% of peak heart rate; HRpeak ) 2 d wk-1 at the clinic (TG) or a control group (CG) given 2 introductory AIT sessions and advised to continue training. Directly assessed peak oxygen uptake ( V ˙ O 2 peak ) increased in the TG after 3 months (2.3 [0.6-4.4] mL kg-1 min-1 , Cohen's d = 0.33[-4.63 to 4.30], P = 0.04), 6 months (2.7 [0.5-4.8] mL kg-1 min-1 , Cohen's d = 0.42[-4.73 to 4.11], P = 0.02) and 1 year (4.6 [2.3-6.8] mL kg-1 min-1 , Cohen's d = 0.70[-4.31 to 4.10], P < 0.001) compared to the CG. One-year cardiac effects revealed higher HRpeak (7 [2-11] b min-1 , Cohen's d = 0.34[-8.48 to 8.65], P = 0.01), while peak stroke volume tended to be higher (0.9 [-0.2 to 2.0] mL b-1 , Cohen's d = 0.35[-1.62 to 2.01], P = 0.11) in the TG compared to the CG. Conventional risk factors (body weight, waist circumference, blood pressure, and lipids/glucose) remained unaltered in both groups. One-year AIT adherence rates were 15/25 (TG; different from CG: P < 0.001) and 0/23 (CG). AIT was successfully included in long-term collaborative care of outpatients with schizophrenia and yielded improved V ˙ O 2 peak , advocating this model for aerobic capacity improvement and CVD risk reduction in future treatment.
Collapse
Affiliation(s)
- Mathias Forsberg Brobakken
- Department of Mental Health, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.,Department of Østmarka, Division of Mental Health Care, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Mona Nygård
- Department of Mental Health, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.,Department of Østmarka, Division of Mental Health Care, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Ismail Cüneyt Güzey
- Department of Mental Health, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.,Department of Research and Development, Division of Mental Health Care, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Gunnar Morken
- Department of Mental Health, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.,Department of Østmarka, Division of Mental Health Care, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Solveig Klaebo Reitan
- Department of Mental Health, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.,Department of Research and Development, Division of Mental Health Care, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Jørn Heggelund
- Department of Mental Health, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.,Regional Centre for Healthcare Improvement, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Einar Vedul-Kjelsaas
- Department of Mental Health, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.,Department of Research and Development, Division of Mental Health Care, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Eivind Wang
- Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.,Faculty of Health and Social Sciences, Molde University College, Molde, Norway.,Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| |
Collapse
|
35
|
Beever AT, Tripp TR, Zhang J, MacInnis MJ. NIRS-derived skeletal muscle oxidative capacity is correlated with aerobic fitness and independent of sex. J Appl Physiol (1985) 2020; 129:558-568. [PMID: 32702279 PMCID: PMC7517427 DOI: 10.1152/japplphysiol.00017.2020] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 06/26/2020] [Accepted: 07/19/2020] [Indexed: 01/03/2023] Open
Abstract
Near-infrared spectroscopy (NIRS) provides a simple and reliable measure of skeletal muscle oxidative capacity; however, its relationship to aerobic fitness and sex are unclear. We hypothesized that NIRS-derived oxidative capacity in the vastus lateralis (VL) and medial gastrocnemius (MG) would be correlated with indices of aerobic fitness and independent of sex. Twenty-six participants (13 males, 13 females) performed ramp- and step-incremental tests to volitional exhaustion on separate days to establish maximal oxygen uptake (V̇o2max), peak power output (PPO), lactate threshold (LT), gas exchange threshold (GET), respiratory compensation point (RCP), and maximal fat oxidation (MFO). Data were normalized to lean body mass to account for sex-based differences in body composition. Exercise tests were preceded by duplicate measurements of NIRS-derived oxidative capacity on the VL and MG muscles (i.e., repeated arterial occlusions following a brief set of muscle contractions). Skeletal muscle oxidative capacity for the VL (means ± SD: 21.9 ± 4.6 s) and MG (22.5 ± 6.1 s) were similar but unrelated (r2 = 0.03, P = 0.39). Skeletal muscle oxidative capacity for the VL, but not the MG (P > 0.05 for all variables), was significantly correlated with V̇o2max (r2 = 0.24; P = 0.01), PPO (r2 = 0.23; P = 0.01), LT (r2 = 0.23; P = 0.01), GET (r2 = 0.23; P = 0.01), and RCP (r2 = 0.27; P = 0.006). MFO was not correlated with VL or MG skeletal muscle oxidative capacity (P > 0.05). Females (54.9 ± 4.5 mL·kg LBM-1·min-1) and males (56.0 ± 6.2 mL·kg LBM-1·min-1), matched for V̇o2max (P = 0.62), had similar NIRS-derived oxidative capacities for VL (20.7 ± 4.4 vs. 23.2 ± 4.6 s; P = 0.18) and MG (24.4 ± 6.8 vs. 20.5 ± 4.8 s; P = 0.10). Overall, NIRS-derived skeletal muscle oxidative capacity in VL is indicative of aerobic fitness and independent of sex in humans.NEW & NOTEWORTHY Near-infrared spectroscopy (NIRS) can be used to measure skeletal muscle oxidative capacity. Here, we demonstrated that NIRS-derived skeletal muscle oxidative capacity of the vastus lateralis was independent of sex, reliable across and within days, and correlated with maximal and submaximal indices of aerobic fitness, including maximal oxygen uptake, lactate threshold, and respiratory compensation point. These findings highlight the utility of NIRS for investigating skeletal muscle oxidative capacity in females and males.
Collapse
Affiliation(s)
- Austin T Beever
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Thomas R Tripp
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Jenny Zhang
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Martin J MacInnis
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| |
Collapse
|
36
|
Gifford JR, Hanson BE, Proffit M, Wallace T, Kofoed J, Griffin G, Hanson M. Indices of leg resistance artery function are independently related to cycling V̇O 2 max. Physiol Rep 2020; 8:e14551. [PMID: 32812353 PMCID: PMC7435036 DOI: 10.14814/phy2.14551] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 07/26/2020] [Indexed: 12/30/2022] Open
Abstract
PURPOSE While maximum blood flow influences one's maximum rate of oxygen consumption (V̇O2 max), with so many indices of vascular function, it is still unclear if vascular function is related to V̇O2 max in healthy, young adults. The purpose of this study was to determine if several common vascular tests of conduit artery and resistance artery function provide similar information about vascular function and the relationship between vascular function and V̇O2 max. METHODS Twenty-two healthy adults completed multiple assessments of leg vascular function, including flow-mediated dilation (FMD), reactive hyperemia (RH), passive leg movement (PLM), and rapid onset vasodilation (ROV). V̇O2 max was assessed with a graded exercise test on a cycle ergometer. RESULTS Indices associated with resistance artery function (e.g., peak flow during RH, PLM, and ROV) were generally related to each other (r = 0.47-77, p < .05), while indices derived from FMD were unrelated to other tests (p < .05). Absolute V̇O2 max (r = 0.57-0.73, p < .05) and mass-specific V̇O2 max (r = 0.41-0.46, p < .05) were related to indices of resistance artery function, even when controlling for factors like body mass and sex. FMD was only related to mass-specific V̇O2 max after statistically controlling for baseline artery diameter (r = 0.44, p < .05). CONCLUSION Indices of leg resistance artery function (e.g., peak flow during RH, PLM, and ROV) relate well to each other and account for ~30% of the variance in V̇O2 max not accounted for by other factors, like body mass and sex. Vascular interventions should focus on improving indices of resistance artery function, not conduit artery function, when seeking to improve exercise capacity.
Collapse
Affiliation(s)
- Jayson R. Gifford
- Department of Exercise SciencesBrigham Young UniversityProvoUTUSA
- Program of GerontologyBrigham Young UniversityProvoUTUSA
| | - Brady E. Hanson
- Department of Exercise SciencesBrigham Young UniversityProvoUTUSA
| | - Meagan Proffit
- Department of Exercise SciencesBrigham Young UniversityProvoUTUSA
- Program of GerontologyBrigham Young UniversityProvoUTUSA
| | - Taysom Wallace
- Department of Exercise SciencesBrigham Young UniversityProvoUTUSA
| | - Jason Kofoed
- Department of Exercise SciencesBrigham Young UniversityProvoUTUSA
| | - Garrett Griffin
- Department of Exercise SciencesBrigham Young UniversityProvoUTUSA
| | - Melina Hanson
- Department of Exercise SciencesBrigham Young UniversityProvoUTUSA
| |
Collapse
|
37
|
Molinger J, Pastva AM, Whittle J, Wischmeyer PE. Novel approaches to metabolic assessment and structured exercise to promote recovery in ICU survivors. Curr Opin Crit Care 2020; 26:369-378. [PMID: 32568800 PMCID: PMC8104451 DOI: 10.1097/mcc.0000000000000748] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE OF REVIEW Survivorship or addressing impaired quality of life (QoL) in ICU survivors has been named 'the defining challenge of critical care' for this century to address this challenge; in addition to optimal nutrition, we must learn to employ targeted metabolic/muscle assessment techniques and utilize structured, progressive ICU rehabilitative strategies. RECENT FINDINGS Objective measurement tools such as ccardiopulmonary exercise testing (CPET) and muscle-specific ultrasound show great promise to assess/treat post-ICU physical dysfunction. CPET is showing that systemic mitochondrial dysfunction may underlie development and persistence of poor post-ICU functional recovery. Finally, recent data indicate that we are poor at delivering effective, early ICU rehabilitation and that there is limited benefit of currently employed later ICU rehabilitation on ICU-acquired weakness and QoL outcomes. SUMMARY The combination of nutrition with effective, early rehabilitation is highly likely to be essential to optimize muscle mass/strength and physical function in ICU survivors. Currently, technologies such as muscle-specific ultrasound and CPET testing show great promise to guide ICU muscle/functional recovery. Further, we must evolve improved ICU-rehabilitation strategies, as current methods are not consistently improving outcomes. In conclusion, we must continue to look to other areas of medicine and to athletes if we hope to ultimately improve 'ICU Survivorship'.
Collapse
Affiliation(s)
- Jeroen Molinger
- Duke University School of Medicine, Department of Anesthesiology, Center for Perioperative Organ Protection (CPOP), Duke Human Pharmacology and Physiology Lab (HPPL), Durham, North Carolina, USA
- Department of Intensive Care Medicine, Erasmus MC, Erasmus University Rotterdam, Rotterdam, The Netherlands
| | - Amy M Pastva
- Duke University School of Medicine, Department of Orthopedic Surgery, Division of Physical Therapy, and Duke Claude D. Pepper Older Americans Independence Center, Durham, North Carolina, USA
| | - John Whittle
- Duke University School of Medicine, Department of Anesthesiology, Center for Perioperative Organ Protection (CPOP), Duke Human Pharmacology and Physiology Lab (HPPL), Durham, North Carolina, USA
| | - Paul E Wischmeyer
- Duke University School of Medicine, Department of Anesthesiology, Center for Perioperative Organ Protection (CPOP), Duke Human Pharmacology and Physiology Lab (HPPL), Durham, North Carolina, USA
| |
Collapse
|
38
|
Zubac D, Ivančev V, Valić Z, Šimunič B. Long-lasting exercise involvement protects against decline in V̇O 2max and V̇O 2 kinetics in moderately active women. Appl Physiol Nutr Metab 2020; 46:108-116. [PMID: 32640173 DOI: 10.1139/apnm-2020-0307] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
We studied the effects of age on different physiological parameters, including those derived from (i) maximal cardiopulmonary exercise testing (CPET), (ii) moderate-intensity step transitions, and (iii) tensiomyography (TMG)-derived variables in moderately active women. Twenty-eight women (age, 19 to 53 years), completed 3 laboratory visits, including baseline data collection, TMG assessment, maximal oxygen uptake test via CPET, and a step-transition test from 20 W to a moderate-intensity cycling power output (PO), corresponding to oxygen uptake at 90% gas exchange threshold. During the step transitions, breath-by-breath pulmonary oxygen uptake, near infrared spectroscopy derived muscle deoxygenation (ΔHHb), and beat-by-beat cardiovascular response were continuously monitored. There were no differences observed between the young and middle-aged women in their maximal oxygen uptake and peak PO, while the maximal heart rate (HR) was 12 bpm lower in middle-aged compared with young (p = 0.016) women. Also, no differences were observed between the age groups in τ pulmonary oxygen uptake, ΔHHb, and τHR during on-transients. The first regression model showed that age did not attenuate the maximal CPET capacity in the studied population (p = 0.638), while in the second model a faster τ pulmonary oxygen uptake, combined with shorter TMG-derived contraction time (Tc) of the vastus lateralis (VL), were associated with a higher maximal oxygen uptake (∼30% of explained variance, p = 0.039). In conclusion, long lasting exercise involvement protects against a maximal oxygen uptake and τpulmonary oxygen uptake deterioration in moderately active women. Novelty: Faster τ pulmonary oxygen uptake and shorter Tc of the VL explain 33% of the variance in superior maximal oxygen uptake attainment. No differences between age groups were found in τ pulmonary oxygen uptake, τΔHHb, and τHR during on-transients.
Collapse
Affiliation(s)
- Damir Zubac
- Institute for Kinesiology Research, Science and Research Center of Koper, Koper, Slovenia.,Faculty of Kinesiology, University of Split, Split, Croatia
| | | | - Zoran Valić
- Department of Integrative Physiology, University of Split, School of Medicine, Split, Croatia
| | - Boštjan Šimunič
- Institute for Kinesiology Research, Science and Research Center of Koper, Koper, Slovenia
| |
Collapse
|
39
|
Larsen FJ, Schiffer TA, Zinner C, Willis SJ, Morales‐Alamo D, Calbet JA, Boushel R, Holmberg H. Mitochondrial oxygen affinity increases after sprint interval training and is related to the improvement in peak oxygen uptake. Acta Physiol (Oxf) 2020; 229:e13463. [PMID: 32144872 DOI: 10.1111/apha.13463] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/28/2020] [Accepted: 03/02/2020] [Indexed: 01/16/2023]
Abstract
AIMS The body responds to exercise training by profound adaptations throughout the cardiorespiratory and muscular systems, which may result in improvements in maximal oxygen consumption (VO2 peak) and mitochondrial capacity. By convenience, mitochondrial respiration is often measured at supra-physiological oxygen levels, an approach that ignores any potential regulatory role of mitochondrial affinity for oxygen (p50mito ) at physiological oxygen levels. METHODS In this study, we examined the p50mito of mitochondria isolated from the Vastus lateralis and Triceps brachii in 12 healthy volunteers before and after a training intervention with seven sessions of sprint interval training using both leg cycling and arm cranking. The changes in p50mito were compared to changes in whole-body VO2 peak. RESULTS We here show that p50mito is similar in isolated mitochondria from the Vastus (40 ± 3.8 Pa) compared to Triceps (39 ± 3.3) but decreases (mitochondrial oxygen affinity increases) after seven sessions of sprint interval training (to 26 ± 2.2 Pa in Vastus and 22 ± 2.7 Pa in Triceps, both P < .01). The change in VO2 peak modelled from changes in p50mito was correlated to actual measured changes in VO2 peak (R2 = .41, P = .002). CONCLUSION Together with mitochondrial respiratory capacity, p50mito is a critical factor when measuring mitochondrial function, it can decrease with sprint interval training and should be considered in the integrative analysis of the oxygen cascade from lung to mitochondria.
Collapse
Affiliation(s)
- Filip J. Larsen
- Åstrand Laboratory The Swedish School of Sport and Health Sciences Stockholm Sweden
| | - Tomas A. Schiffer
- Department of Physiology and Pharmacology Karolinska Institutet Stockholm Sweden
| | - Christoph Zinner
- Department of Sport University of Applied Sciences for Police and Administration of Hesse Wiesbaden Germany
| | - Sarah J. Willis
- Institute of Sport Sciences University of Lausanne Lausanne Switzerland
| | - David Morales‐Alamo
- Department of Physical Education and Research Institute of Biomedical and Health Sciences (IUIBS) University of Las Palmas de Gran Canaria Gran Canaria Spain
| | - Jose A.L. Calbet
- Department of Physical Education and Research Institute of Biomedical and Health Sciences (IUIBS) University of Las Palmas de Gran Canaria Gran Canaria Spain
- School of Kinesiology Faculty of Education The University of British Columbia Vancouver BC Canada
- Department of Physical Performance The Norwegian School of Sport Sciences Oslo Norway
| | - Robert Boushel
- School of Kinesiology Faculty of Education The University of British Columbia Vancouver BC Canada
| | - Hans‐Christer Holmberg
- Swedish Winter Sports Research Centre Department of Health SciencesMid Sweden University Östersund Sweden
| |
Collapse
|
40
|
Øvretveit K. High-Intensity, Non-Sport-Specific Strength and Conditioning for Brazilian Jiu-Jitsu Athletes: Theoretical and Practical Considerations. Strength Cond J 2020. [DOI: 10.1519/ssc.0000000000000542] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
41
|
Skattebo Ø, Capelli C, Rud B, Auensen M, Calbet JAL, Hallén J. Increased oxygen extraction and mitochondrial protein expression after small muscle mass endurance training. Scand J Med Sci Sports 2020; 30:1615-1631. [PMID: 32403173 DOI: 10.1111/sms.13707] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 04/06/2020] [Accepted: 05/04/2020] [Indexed: 12/14/2022]
Abstract
When exercising with a small muscle mass, the mass-specific O2 delivery exceeds the muscle oxidative capacity resulting in a lower O2 extraction compared with whole-body exercise. We elevated the muscle oxidative capacity and tested its impact on O2 extraction during small muscle mass exercise. Nine individuals conducted six weeks of one-legged knee extension (1L-KE) endurance training. After training, the trained leg (TL) displayed 45% higher citrate synthase and COX-IV protein content in vastus lateralis and 15%-22% higher pulmonary oxygen uptake ( V ˙ O 2 peak ) and peak power output ( W ˙ peak ) during 1L-KE than the control leg (CON; all P < .05). Leg O2 extraction (catheters) and blood flow (ultrasound Doppler) were measured while both legs exercised simultaneously during 2L-KE at the same submaximal power outputs (real-time feedback-controlled). TL displayed higher O2 extraction than CON (main effect: 1.7 ± 1.6% points; P = .010; 40%-83% of W ˙ peak ) with the largest between-leg difference at 83% of W ˙ peak (O2 extraction: 3.2 ± 2.2% points; arteriovenous O2 difference: 7.1 ± 4.8 mL· L-1 ; P < .001). At 83% of W ˙ peak , muscle O2 conductance (DM O2 ; Fick law of diffusion) and the equilibration index Y were higher in TL (P < .01), indicating reduced diffusion limitations. The between-leg difference in O2 extraction correlated with the between-leg ratio of citrate synthase and COX-IV (r = .72-.73; P = .03), but not with the difference in the capillary-to-fiber ratio (P = .965). In conclusion, endurance training improves O2 extraction during small muscle mass exercise by elevating the muscle oxidative capacity and the recruitment of DM O2, especially evident during high-intensity exercise exploiting a larger fraction of the muscle oxidative capacity.
Collapse
Affiliation(s)
- Øyvind Skattebo
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Carlo Capelli
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Bjarne Rud
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Marius Auensen
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Jose A L Calbet
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway.,Department of Physical Education, University of Las Palmas de Gran Canaria, Spain.,Research Institute of Biomedical and Health Sciences (IUIBS), Las Palmas de Gran Canaria, Spain
| | - Jostein Hallén
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| |
Collapse
|
42
|
Johnson MA, Williams NC, Graham AW, Ingram LAL, Cooper SB, Sharpe GR. Effects of Prior Upper Body Exercise on the 3-min All-Out Cycling Test in Men. Med Sci Sports Exerc 2020; 52:2402-2411. [PMID: 32366795 DOI: 10.1249/mss.0000000000002395] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Prior upper body exercise reduces the curvature constant (W') of the hyperbolic power-duration relationship without affecting critical power. This study tested the hypothesis that prior upper body exercise reduces the work done over the end-test power (WEP; analog of W') during a 3-min all-out cycling test (3MT) without affecting the end-test power (EP; analog of critical power). METHODS Ten endurance-trained men (V˙O2max = 62 ± 5 mL·kg·min) performed a 3MT without (CYC) and with (ARM-CYC) prior severe-intensity, intermittent upper body exercise. EP was calculated as the mean power output over the last 30 s of the 3MT, whereas WEP was calculated as the power-time integral above EP. RESULTS At the start of the 3MT, plasma [La] (1.8 ± 0.4 vs 14.1 ± 3.4 mmol·L) and [H] (42.8 ± 3.1 vs 58.6 ± 5.5 nmol·L) were higher, whereas the strong ion difference (41.4 ± 2.2 vs 30.9 ± 4.6 mmol·L) and [HCO3] (27.0 ± 1.9 vs 16.9 ± 3.2 mmol·L) were lower during ARM-CYC than CYC (P < 0.010). EP was 12% lower during the 3MT of ARM-CYC (298 ± 52 W) than CYC (338 ± 60 W; P < 0.001), whereas WEP was not different (CYC: 12.8 ± 3.3 kJ vs ARM-CYC: 13.5 ± 4.1 kJ, P = 0.312). EP in CYC was positively correlated with the peak [H] (r = 0.78, P = 0008) and negatively correlated with the lowest [HCO3] (r = -0.74, P = 0.015). CONCLUSIONS These results suggest that EP during a 3MT in endurance-trained men is sensitive to fatigue-related ionic perturbation.
Collapse
Affiliation(s)
- Michael A Johnson
- Exercise and Health Research Group, Sport, Health and Performance Enhancement (SHAPE) Research Centre, School of Science and Technology, Nottingham Trent University, Nottingham, UNITED KINGDOM
| | | | | | | | | | | |
Collapse
|
43
|
Gifford JR, Bloomfield T, Davis T, Addington A, McMullin E, Wallace T, Proffit M, Hanson B. The effect of the speed and range of motion of movement on the hyperemic response to passive leg movement. Physiol Rep 2020; 7:e14064. [PMID: 31004411 PMCID: PMC6474844 DOI: 10.14814/phy2.14064] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 03/27/2019] [Indexed: 11/24/2022] Open
Abstract
Passive leg movement (PLM)-induced hyperemia is used to assess the function of the vascular endothelium. This study sought to determine the impact of movement speed and range of motion (ROM) on the hyperemic response to PLM and determine if the currently recommended protocol of moving the leg through a 90° ROM at 180°/sec provides a peak hyperemic response to PLM. 11 healthy adults underwent multiple bouts of PLM, in which either movement speed (60-240°/sec) or ROM (30-120° knee flexion) were varied. Femoral artery blood flow (Doppler Ultrasound) and mean arterial pressure (MAP; photoplethysmography) were measured throughout. Movement speed generally exhibited positive linear relationships with the hyperemic response to PLM, eliciting ~15-20% increase in hyperemia and conductance for each 30°/sec increase in speed (P < 0.05). However, increasing the movement speed above 180°/sec was physically difficult and seemingly impractical to implement. ROM exhibited curvilinear relationships (P<0.05) with hyperemia and conductance, which peaked at 90°, such that a 30° increase or decrease in ROM from 90° resulted in a 10-40% attenuation (P < 0.05) in the hyperemic response. Alterations in the balance of antegrade and retrograde flow appear to play a role in this attenuation. Movement speed and ROM have a profound impact on PLM-induced hyperemia. When using PLM to assess vascular endothelial function, it is recommended to perform the test at the traditional 180°/sec with 90° ROM, which offers a near peak hyperemic response, while maintaining test feasibility.
Collapse
Affiliation(s)
- Jayson R Gifford
- Department of Exercise Sciences, Brigham Young University, Provo, Utah.,Program of Gerontology, Brigham Young University, Provo, Utah
| | - Travis Bloomfield
- Department of Exercise Sciences, Brigham Young University, Provo, Utah
| | - Trevor Davis
- Department of Exercise Sciences, Brigham Young University, Provo, Utah
| | - Amy Addington
- Department of Exercise Sciences, Brigham Young University, Provo, Utah
| | - Erin McMullin
- Department of Exercise Sciences, Brigham Young University, Provo, Utah
| | - Taysom Wallace
- Department of Exercise Sciences, Brigham Young University, Provo, Utah
| | - Meagan Proffit
- Department of Exercise Sciences, Brigham Young University, Provo, Utah
| | - Brady Hanson
- Department of Exercise Sciences, Brigham Young University, Provo, Utah
| |
Collapse
|
44
|
Hanson BE, Proffit M, Gifford JR. Vascular function is related to blood flow during high-intensity, but not low-intensity, knee extension exercise. J Appl Physiol (1985) 2020; 128:698-708. [DOI: 10.1152/japplphysiol.00671.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
While vascular function, assessed as the ability of the vasculature to dilate in response to a stimulus, is related to cardiovascular health, its relationship to exercise hyperemia is unclear. This study sought to determine if blood flow during submaximal and maximal exercise is related to vascular function. Nineteen healthy adults completed multiple assessments of vascular function specific to the leg, including passive leg movement (PLM), rapid onset vasodilation (ROV), reactive hyperemia (RH), and flow-mediated dilation (FMD). On a separate day, exercise blood flow (Doppler ultrasound) was assessed in the same leg during various intensities of single-leg, knee-extension (KE) exercise. Vascular function, determined by PLM, ROV, and RH, was related to exercise blood flow at high intensities, including maximum work rate (WRmax) ( r = 0.58–0.77, P < 0.001), but not low intensities, like ~21% WRmax ( r = 0.12–0.34, P = 0.12–0.62). Relationships between multiple indices of vascular function and peak exercise blood flow persisted when controlling for quadriceps mass and exercise work rate ( P < 0.05), indicating vascular function is independently related to the blood flow response to intense exercise. When divided into two groups based upon the magnitude of the PLM response, subjects with a lower PLM response exhibited lower exercise flow at several absolute work rates, as well as lower peak flow ( P < 0.05). In conclusion, leg flow during dynamic exercise is independently correlated with multiple different indices of microvascular function. Thus microvascular function appears to modulate the hyperemic response to high-intensity, but not low-intensity, exercise. NEW & NOTEWORTHY While substantial evidence indicates that individuals with lower vascular function are at greater risk for cardiovascular disease, with many redundant vasodilator pathways present during exercise, it has been unclear if low vascular function actually impacts blood flow during exercise. This study provides evidence that vascular function, assessed by multiple noninvasive methods, is related to the blood flow response to high-intensity leg exercise in healthy young adults. Importantly, healthy young adults with lower levels of vascular function, particularly microvascular function, exhibit lower blood flow during high-intensity, and maximal knee extension exercise. Thus it appears that in addition to increasing one’s risk of cardiovascular disease, lower vascular function is also related to a blunted blood flow response during high-intensity exercise.
Collapse
Affiliation(s)
- Brady E. Hanson
- Department of Exercise Sciences, Brigham Young University, Provo, Utah
| | - Meagan Proffit
- Department of Exercise Sciences, Brigham Young University, Provo, Utah
| | - Jayson R. Gifford
- Department of Exercise Sciences, Brigham Young University, Provo, Utah
- Program of Gerontology, Brigham Young University, Provo, Utah
| |
Collapse
|
45
|
Broxterman RM, Hoff J, Wagner PD, Richardson R. Determinants of the diminished exercise capacity in patients with chronic obstructive pulmonary disease: looking beyond the lungs. J Physiol 2020; 598:599-610. [PMID: 31856306 PMCID: PMC6995414 DOI: 10.1113/jp279135] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 12/06/2019] [Indexed: 12/21/2022] Open
Abstract
KEY POINTS Peak oxygen uptake, a primary determinant of prognosis, mortality and quality of life, is diminished in patients with chronic obstructive pulmonary disease (COPD), with mounting evidence supporting an important role for peripheral dysfunction, particularly within skeletal muscle. In patients with severe COPD and activity-matched controls, muscle oxygen transport and utilization were assessed at peak effort during single-leg knee-extensor exercise (KE), where ventilation is assumed to be submaximal. This strategy removes ventilation as the major constraint to exercise capacity in COPD, allowing maximal muscle function to be attained and evaluated. During maximal KE, both convective arterial oxygen delivery to the skeletal muscle microvasculature and subsequent diffusive oxygen delivery to the mitochondria were diminished in patients with COPD compared to control subjects. These findings emphasize the importance of factors, beyond the lungs, that influence exercise capacity in this patient population and may, ultimately, influence the prognosis, mortality and quality of life for patients with COPD. ABSTRACT Peak oxygen uptake ( V ̇ O 2 peak ), a primary determinant of prognosis, mortality and quality of life, is diminished in patients with chronic obstructive pulmonary disease (COPD). Mounting evidence supports an important role of the periphery, particularly skeletal muscle, in the diminished V ̇ O 2 peak with COPD. However, the peripheral determinants of V ̇ O 2 peak have not been comprehensively assessed in this cohort. Thus, the hypothesis was tested that both muscle convective and diffusive oxygen (O2 ) transport, and therefore skeletal muscle peak O2 uptake ( V ̇ M O 2 peak ), are diminished in patients with COPD compared to matched healthy controls, even when ventilatory limitations (i.e. attainment of maximal ventilation) are minimized by using small muscle mass exercise. Muscle O2 transport and utilization were assessed at peak exercise from femoral arterial and venous blood samples and leg blood flow (by thermodilution) in eight patients with severe COPD (forced expiratory volume in 1s (FEV1 ) ± SEM = 0.9 ± 0.1 l, 30% of predicted) and eight controls during single-leg knee-extensor exercise. Both muscle convective O2 delivery (0.44 ± 0.06 vs. 0.69 ± 0.07 l min-1 , P < 0.05) and muscle diffusive O2 conductance (6.6 ± 0.8 vs. 10.4 ± 0.9 ml min-1 mmHg-1 , P < 0.05) were ∼1/3 lower in patients with COPD than controls, resulting in an attenuated V ̇ M O 2 peak in the patients (0.27 ± 0.04 vs. 0.42 ± 0.05 l min-1 , P < 0.05). When cardiopulmonary limitations to exercise are minimized, the convective and diffusive determinants of V ̇ M O 2 peak , at the level of the skeletal muscle, are greatly attenuated in patients with COPD. These findings emphasize the importance of factors, beyond the lungs, that may ultimately influence this population's prognosis, mortality and quality of life.
Collapse
Affiliation(s)
- Ryan M. Broxterman
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah
- Geriatric Research, Education, and Clinical Center, VA Medical Center, Salt Lake City, Utah
| | - Jan Hoff
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway
| | - Peter D. Wagner
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Russell.S. Richardson
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah
- Geriatric Research, Education, and Clinical Center, VA Medical Center, Salt Lake City, Utah
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| |
Collapse
|
46
|
Wiggins CC, Constantini K, Paris HL, Mickleborough TD, Chapman RF. Ischemic Preconditioning, O2 Kinetics, and Performance in Normoxia and Hypoxia. Med Sci Sports Exerc 2019; 51:900-911. [PMID: 30601792 DOI: 10.1249/mss.0000000000001882] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
INTRODUCTION Ischemic preconditioning (IPC) before exercise has been shown to be a novel approach to improve performance in different exercise modes in normoxia (NORM). Few studies have been conducted examining potential mechanisms behind these improvements, and less has been done examining its influence during exercise in hypoxia (HYP). Oxygen uptake and extraction kinetics are factors that have been implicated as possible determinants of cycling performance. We hypothesized that IPC would lead to improvements in oxygen extraction and peripheral blood flow kinetics, and this would translate to improvements in cycling time trial (TT) performance in both NORM and HYP. METHODS Thirteen men (age, 24 ± 7 yr; V˙O2max, 63.1 ± 5.1 mL·kg·min) participated in the study. Subjects completed trials of each combination of normobaric HYP (FiO2 = 0.16, simulating ~8000 ft/2500 m) or NORM (FiO2 = 0.21) with preexercise IPC protocol (4 × 5 min at 220 mm Hg) or SHAM procedure. Trials included submaximal constant load cycle exercise bouts (power outputs of 15% below gas exchange threshold, and 85% of V˙O2max), and a 5-km cycling performance TT. RESULTS Ischemic preconditioning significantly improved 5-km TT time in NORM by 0.9% ± 1.8% compared with SHAM (IPC, 491.2 ± 35.2 s vs SHAM, 495.9 ± 36.0 s; P < 0.05). Ischemic preconditioning did not alter 5-km TT performance times in HYP (P = 0.231). Ischemic preconditioning did, however, improve tissue oxygen extraction in HYP (deoxygenated hemoglobin/myoglobin: IPC, 21.23 ± 10.95 μM; SHAM, 19.93 ± 9.91 μM; P < 0.05) during moderate-intensity exercise. CONCLUSIONS Our data confirm that IPC is an effective ergogenic aid for athletes performing 5-km cycling TT bouts in NORM. Ischemic preconditioning did mitigate the declines in tissue oxygen during moderate-intensity exercise in HYP, but this did not translate to a significant effect on mean group performance. These data suggest that IPC may be of benefit for athletes training and competing in NORM.
Collapse
Affiliation(s)
- Chad C Wiggins
- Department of Kinesiology, School of Public Health-Bloomington, Indiana University, Bloomington, IN.,Department of Anesthesiology, Mayo Clinic, Rochester, MN
| | - Keren Constantini
- Department of Kinesiology, School of Public Health-Bloomington, Indiana University, Bloomington, IN
| | - Hunter L Paris
- Department of Kinesiology, School of Public Health-Bloomington, Indiana University, Bloomington, IN
| | - Timothy D Mickleborough
- Department of Kinesiology, School of Public Health-Bloomington, Indiana University, Bloomington, IN
| | - Robert F Chapman
- Department of Kinesiology, School of Public Health-Bloomington, Indiana University, Bloomington, IN
| |
Collapse
|
47
|
Caen K, Vermeire K, Pogliaghi S, Moerman A, Niemeijer V, Bourgois JG, Boone J. Aerobic Interval Training Impacts Muscle and Brain Oxygenation Responses to Incremental Exercise. Front Physiol 2019; 10:1195. [PMID: 31616312 PMCID: PMC6764183 DOI: 10.3389/fphys.2019.01195] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 09/03/2019] [Indexed: 11/18/2022] Open
Abstract
The purpose of the present study was to assess the effects of aerobic interval training on muscle and brain oxygenation to incremental ramp exercise. Eleven physically active subjects performed a 6-week interval training period, proceeded and followed by an incremental ramp exercise to exhaustion (25 W min–1). Throughout the tests pulmonary gas exchange and muscle (Vastus Lateralis) and brain (prefrontal cortex) oxygenation [concentration of deoxygenated and oxygenated hemoglobin, HHb and O2Hb, and tissue oxygenation index (TOI)] were continuously recorded. Following the training intervention V.O2peak had increased with 7.8 ± 5.0% (P < 0.001). The slope of the decrease in muscle TOI had decreased (P = 0.017) 16.6 ± 6.4% and the amplitude of muscle HHb and totHb had increased (P < 0.001) 40.4 ± 15.8 and 125.3 ± 43.1%, respectively. The amplitude of brain O2Hb and totHb had increased (P < 0.05) 40.1 ± 18.7 and 26.8 ± 13.6%, respectively. The training intervention shifted breakpoints in muscle HHb, totHb and TOI, and brain O2Hb, HHb, totHb and TOI to a higher absolute work rate and V.O2 (P < 0.05). The relative (in %) change in V.O2peak was significantly correlated to relative (in %) change slope of muscle TOI (r = 0.69, P = 0.011) and amplitude of muscle HHb (r = 0.72, P = 0.003) and totHb (r = 0.52, P = 0.021), but not to changes in brain oxygenation. These results indicate that interval training affects both muscle and brain oxygenation, coinciding with an increase in aerobic fitness (i.e., V.O2peak). The relation between the change in V.O2peak and muscle but not brain oxygenation suggests that brain oxygenation per se is not a primary factor limiting exercise tolerance during incremental exercise.
Collapse
Affiliation(s)
- Kevin Caen
- Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium
| | - Kobe Vermeire
- Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium
| | - Silvia Pogliaghi
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Annelies Moerman
- Department of Anesthesiology, Ghent University Hospital, Ghent, Belgium
| | - Victor Niemeijer
- Department of Sports Medicine, Elkerliek Hospital, Helmond, Netherlands
| | | | - Jan Boone
- Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium
| |
Collapse
|
48
|
Oyake K, Baba Y, Ito N, Suda Y, Murayama J, Mochida A, Kondo K, Otaka Y, Momose K. Cardiorespiratory factors related to the increase in oxygen consumption during exercise in individuals with stroke. PLoS One 2019; 14:e0217453. [PMID: 31596863 PMCID: PMC6785174 DOI: 10.1371/journal.pone.0217453] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Accepted: 09/24/2019] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Understanding the cardiorespiratory factors related to the increase in oxygen consumption ([Formula: see text]) during exercise is essential for improving cardiorespiratory fitness in individuals with stroke. However, cardiorespiratory factors related to the increase in [Formula: see text] during exercise in these individuals have not been examined using multivariate analysis. This study aimed to identify cardiorespiratory factors related to the increase in [Formula: see text] during a graded exercise in terms of respiratory function, cardiac function, and the ability of skeletal muscles to extract oxygen. METHODS Eighteen individuals with stroke (aged 60.1 ± 9.4 years, 67.1 ± 30.8 days poststroke) underwent a graded exercise test for the assessment of cardiorespiratory response to exercise. The increases in [Formula: see text] from rest to first threshold and that from rest to peak exercise were measured as a dependent variable. The increases in respiratory rate, tidal volume, minute ventilation, heart rate, stroke volume, cardiac output, and arterial-venous oxygen difference from rest to first threshold and those from rest to peak exercise were measured as the independent variables. RESULTS From rest to first threshold, the increases in arterial-venous oxygen difference (β = 0.711) and cardiac output (β = 0.572) were significant independent variables for the increase in [Formula: see text] (adjusted R2 = 0.877 p < 0.001). Similarly, from rest to peak exercise, the increases in arterial-venous oxygen difference (β = 0.665) and cardiac output (β = 0.636) were significant factors related to the increase in [Formula: see text] (adjusted R2 = 0.923, p < 0.001). CONCLUSION Our results suggest that the ability of skeletal muscle to extract oxygen is a major cardiorespiratory factor related to the increase in [Formula: see text] during exercise testing in individuals with stroke. For improved cardiorespiratory fitness in individuals with stroke, the amount of functional muscle mass during exercise may need to be increased.
Collapse
Affiliation(s)
- Kazuaki Oyake
- Department of Physical Therapy, School of Health Sciences, Shinshu University, Matsumoto, Nagano, Japan
- Department of Rehabilitation Medicine, Tokyo Bay Rehabilitation Hospital, Narashino, Chiba, Japan
| | - Yasuto Baba
- Department of Rehabilitation Medicine, Tokyo Bay Rehabilitation Hospital, Narashino, Chiba, Japan
| | - Nao Ito
- Department of Rehabilitation Medicine, Tokyo Bay Rehabilitation Hospital, Narashino, Chiba, Japan
| | - Yuki Suda
- Department of Rehabilitation Medicine, Tokyo Bay Rehabilitation Hospital, Narashino, Chiba, Japan
| | - Jun Murayama
- Department of Rehabilitation Medicine, Tokyo Bay Rehabilitation Hospital, Narashino, Chiba, Japan
| | - Ayumi Mochida
- Department of Rehabilitation Medicine, Tokyo Bay Rehabilitation Hospital, Narashino, Chiba, Japan
| | - Kunitsugu Kondo
- Department of Rehabilitation Medicine, Tokyo Bay Rehabilitation Hospital, Narashino, Chiba, Japan
| | - Yohei Otaka
- Department of Rehabilitation Medicine, Tokyo Bay Rehabilitation Hospital, Narashino, Chiba, Japan
- Department of Rehabilitation Medicine I, School of Medicine, Fujita Health University, Toyoake, Aichi, Japan
| | - Kimito Momose
- Department of Physical Therapy, School of Health Sciences, Shinshu University, Matsumoto, Nagano, Japan
- * E-mail:
| |
Collapse
|
49
|
A Prior High-Intensity Exercise Bout Attenuates the Vascular Dysfunction Resulting From a Prolonged Sedentary Bout. J Phys Act Health 2019; 16:916-924. [DOI: 10.1123/jpah.2018-0568] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 06/04/2019] [Accepted: 07/14/2019] [Indexed: 11/18/2022]
Abstract
Background: This study sought to determine the impact of an acute prior bout of high-intensity interval aerobic exercise on attenuating the vascular dysfunction associated with a prolonged sedentary bout. Methods: Ten young (24 ± 1 y) healthy males completed two 3-hour sessions of prolonged sitting with (SIT-EX) and without (SIT) a high-intensity interval aerobic exercise session performed immediately prior. Prior to and 3 hours into the sitting bout, leg vascular function was assessed with the passive leg movement technique, and blood samples were obtained from the lower limb to evaluate changes in oxidative stress (malondialdehyde and superoxide dismutase) and inflammation (interleukin-6). Results: No presitting differences in leg vascular function (assessed via passive leg movement technique-induced hyperemia) were revealed between conditions. After 3 hours of prolonged sitting, leg vascular function was significantly reduced in the SIT condition, but unchanged in the SIT-EX. Lower limb blood samples revealed no alterations in oxidative stress, antioxidant capacity, or inflammation in either condition. Conclusions: This study revealed that lower limb vascular dysfunction was significantly attenuated by an acute presitting bout of high-intensity interval aerobic exercise. Further analysis of lower limb blood samples revealed no changes in circulating oxidative stress or inflammation in either condition.
Collapse
|
50
|
Crossley KW, Porter DA, Ellsworth J, Caldwell T, Feland JB, Mitchell U, Johnson AW, Egget D, Gifford JR. Effect of Cuff Pressure on Blood Flow during Blood Flow-restricted Rest and Exercise. Med Sci Sports Exerc 2019; 52:746-753. [PMID: 31568024 DOI: 10.1249/mss.0000000000002156] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
PURPOSE This study investigated the relationship between blood flow restriction (BFR) cuff pressure and blood flow at rest and during exercise, with the aim of determining if lower cuff pressures will provide an ischemic stimulus comparable to higher pressures. METHODS The relationship between blood flow and cuff pressure at rest was determined by measuring blood flow (Doppler Ultrasound) through the superficial femoral artery (SFA) in 23 adults across a range of pressures (0%-100% Arterial Occlusion Pressure at rest [rAOP]). The interplay between cuff pressure, blood flow and exercise was assessed by determining AOP at rest and during plantar flexion exercise (eAOP) and subsequently measuring the blood flow response to plantar flexion exercise with BFR cuff pressure set to either 40% rAOP or 40% eAOP. RESULTS At rest, a nonlinear relationship between cuff pressure and blood flow through the SFA exhibited a plateau at moderate pressures, with nonsignificant differences in blood flow (~9%, P = 1.0) appearing between pressures ranging from 40% to 80% rAOP. While eAOP was greater than rAOP (229 ± 1.5 mm Hg vs 202 ± 1.5 mm Hg, P < 0.01), blood flow during plantar flexion exercise did not significantly differ (P = 0.49) when applying 40% rAOP or 40% eAOP. CONCLUSIONS Blood flow through the SFA exhibits a nonlinear relationship with cuff pressure, such that cuff pressures in the range of 40% to 80% rAOP reduce blood flow to approximately the same degree. The BFR interventions opting for lower (e.g., 40% AOP), more comfortable pressures will likely provide an ischemic stimulus comparable to that of higher (80% AOP), less-comfortable pressures.
Collapse
Affiliation(s)
- Kent W Crossley
- Department of Exercise Sciences, Brigham Young University, Provo, UT
| | - Doran A Porter
- Department of Exercise Sciences, Brigham Young University, Provo, UT
| | - Joshua Ellsworth
- Department of Exercise Sciences, Brigham Young University, Provo, UT
| | - Tabitha Caldwell
- Department of Exercise Sciences, Brigham Young University, Provo, UT
| | | | | | | | - Dennis Egget
- Department of Statistics, Brigham Young University, Provo, UT
| | | |
Collapse
|