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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] [What about the content of this article? (0)] [Affiliation(s)] [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.
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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
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Haddad T, Spence AL, Peiffer JJ, Blain GM, Brisswalter J, Abbiss CR. Single- Versus Double-Leg Cycling: Small Muscle Mass Exercise Improves Exercise Capacity to a Greater Extent in Older Compared With Younger Population. J Aging Phys Act 2024:1-8. [PMID: 38350440 DOI: 10.1123/japa.2023-0234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 10/12/2023] [Accepted: 11/27/2023] [Indexed: 02/15/2024]
Abstract
Manipulating the amount of muscle mass engaged during exercise can noninvasively inform the contribution of central cardiovascular and peripheral vascular-oxidative functions to endurance performance. To better understand the factors contributing to exercise limitation in older and younger individuals, exercise performance was assessed during single-leg and double-leg cycling. 16 older (67 ± 5 years) and 14 younger (35 ± 5 years) individuals performed a maximal exercise using single-leg and double-leg cycling. The ratio of single-leg to double-leg cycling power (RatioPower SL/DL) was compared between age groups. The association between fitness (peak oxygen consumption, peak power output, and physical activity levels) and RatioPower SL/DL was explored. The RatioPower SL/DL was greater in older compared with younger individuals (1.14 ± 0.11 vs. 1.06 ± 0.08, p = .041). The RatioPower SL/DL was correlated with peak oxygen consumption (r = .886, p < .001), peak power output relative to body mass (r = .854, p < .001), and levels of physical activity (r = .728, p = .003) in the younger but not older subgroup. Reducing the amount of muscle mass engaged during exercise improved exercise capacity to a greater extent in older versus younger population and may reflect a greater reduction in central cardiovascular function compared with peripheral vascular-oxidative function with aging.
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Affiliation(s)
- Toni Haddad
- Centre for Human Performance, School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
- Université Côte d'Azur, LAMHESS, Nice, France
| | - Angela L Spence
- Curtin School of Allied Health, Exercise and Sport Science Discipline, Curtin University, Perth, WA, Australia
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
| | | | | | | | - Chris R Abbiss
- Centre for Human Performance, School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
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Haddad T, Mons V, Meste O, Dempsey JA, Abbiss CR, Brisswalter J, Blain GM. Breathing a low-density gas reduces respiratory muscle force development and marginally improves exercise performance in master athletes. Eur J Appl Physiol 2024; 124:651-665. [PMID: 37973652 DOI: 10.1007/s00421-023-05346-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Accepted: 10/16/2023] [Indexed: 11/19/2023]
Abstract
INTRODUCTION We tested the hypothesis that breathing heliox, to attenuate the mechanical constraints accompanying the decline in pulmonary function with aging, improves exercise performance. METHODS Fourteen endurance-trained older men (67.9 ± 5.9 year, [Formula: see text]O2max: 50.8 ± 5.8 ml/kg/min; 151% predicted) completed two cycling 5-km time trials while breathing room air (i.e., 21% O2-79% N2) or heliox (i.e., 21% O2-79% He). Maximal flow-volume curves (MFVC) were determined pre-exercise to characterize expiratory flow limitation (EFL, % tidal volume intersecting the MFVC). Respiratory muscle force development was indirectly determined as the product of the time integral of inspiratory and expiratory mouth pressure (∫Pmouth) and breathing frequency. Maximal inspiratory and expiratory pressure maneuvers were performed pre-exercise and post-exercise to estimate respiratory muscle fatigue. RESULTS Exercise performance time improved (527.6 ± 38 vs. 531.3 ± 36.9 s; P = 0.017), and respiratory muscle force development decreased during inspiration (- 22.8 ± 11.6%, P < 0.001) and expiration (- 10.8 ± 11.4%, P = 0.003) with heliox compared with room air. EFL tended to be lower with heliox (22 ± 23 vs. 30 ± 23% tidal volume; P = 0.054). Minute ventilation normalized to CO2 production ([Formula: see text]E/[Formula: see text]CO2) increased with heliox (28.6 ± 2.7 vs. 25.1 ± 1.8; P < 0.001). A reduction in MIP and MEP was observed post-exercise vs. pre-exercise but was not different between conditions. CONCLUSIONS Breathing heliox has a limited effect on performance during a 5-km time trial in master athletes despite a reduction in respiratory muscle force development.
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Affiliation(s)
- Toni Haddad
- LAMHESS, Sciences et Techniques des Activités Physiques et Sportives, Université Côte d'Azur, 261 Bd du Mercantour, 06200, Nice, France.
- Centre VADER, Université Côte d'Azur, Nice, France.
- Centre for Exercise and Sport Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia.
| | - Valentin Mons
- LAMHESS, Sciences et Techniques des Activités Physiques et Sportives, Université Côte d'Azur, 261 Bd du Mercantour, 06200, Nice, France
- Centre VADER, Université Côte d'Azur, Nice, France
- LJAD, Université Côte d'Azur, CNRS, Nice, France
| | - Olivier Meste
- Lab I3S, Université Côte d'Azur, CNRS, Sophia Antipolis, Nice, France
| | - Jerome A Dempsey
- John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Chris R Abbiss
- Centre for Exercise and Sport Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
| | - Jeanick Brisswalter
- LAMHESS, Sciences et Techniques des Activités Physiques et Sportives, Université Côte d'Azur, 261 Bd du Mercantour, 06200, Nice, France
- Centre VADER, Université Côte d'Azur, Nice, France
| | - Gregory M Blain
- LAMHESS, Sciences et Techniques des Activités Physiques et Sportives, Université Côte d'Azur, 261 Bd du Mercantour, 06200, Nice, France
- Centre VADER, Université Côte d'Azur, Nice, France
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Haddad T, Mons V, Meste O, Dempsey JA, Abbiss CR, Brisswalter J, Blain GM. Correction: Breathing a low-density gas reduces respiratory muscle force development and marginally improves exercise performance in master athletes. Eur J Appl Physiol 2024; 124:667-668. [PMID: 38286941 DOI: 10.1007/s00421-023-05383-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2024]
Affiliation(s)
- Toni Haddad
- Université Côte d'Azur, LAMHESS, Nice, France.
- Université Cô̂te d'Azur, Centre VADER, Nice, France.
- Centre for Human Performance, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.
| | - Valentin Mons
- Université Côte d'Azur, LAMHESS, Nice, France
- Université Cô̂te d'Azur, Centre VADER, Nice, France
- Université Côte d'Azur, CNRS, LJAD, Nice, France
| | - Olivier Meste
- Université Côte d'Azur, CNRS, I3S, Sophia-Antipolis, France
| | - Jerome A Dempsey
- John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Chris R Abbiss
- Centre for Human Performance, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
| | - Jeanick Brisswalter
- Université Côte d'Azur, LAMHESS, Nice, France
- Université Cô̂te d'Azur, Centre VADER, Nice, France
| | - Gregory M Blain
- Université Côte d'Azur, LAMHESS, Nice, France
- Université Cô̂te d'Azur, Centre VADER, Nice, France
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Da Silva F, Piponnier E, Corcelle B, Blain GM, Gioda J, Colson SS, Monjo F. Submaximal fatiguing eccentric contractions of knee flexors alter leg extrapersonal representation. Heliyon 2023; 9:e18884. [PMID: 37609426 PMCID: PMC10440467 DOI: 10.1016/j.heliyon.2023.e18884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 07/31/2023] [Accepted: 08/01/2023] [Indexed: 08/24/2023] Open
Abstract
This study assessed the immediate and prolonged effects of eccentric-induced fatigue on position sense, utilizing position-pointing tasks, which had not been previously implemented for this purpose. Fifteen healthy adults underwent a fatiguing eccentric protocol that entailed sets of unilateral submaximal contractions of knee flexor muscles until reaching a 20% decrease in maximal isometric torque production. Evaluations of knee flexor neuromuscular function as well as position-pointing tasks at 40° and 70° of knee flexion were conducted prior to the fatiguing eccentric protocol, immediately after (POST), and 24 h after (POST24) exercise termination. To assess neuromuscular fatigue etiology, electrical myostimulations were administered during and after maximal voluntary isometric contractions. At POST, the voluntary activation level and evoked potentiated doublet amplitude at 100 Hz were significantly reduced. In addition, position-pointing errors exhibited a significant increase at POST regardless of the tested angle, with participants positioning the pointer in a more extended position compared to their hidden exercised limb. At POST24, neuromuscular function and position sense parameters had reverted to their baseline levels. The findings of this experiment demonstrate that position-pointing accuracy was impaired immediately after the fatiguing eccentric protocol, manifesting in the presence of both central and peripheral fatigue. As position-pointing accuracy relies heavily on extrapersonal representation of the body at the brain level, acute changes in exercised limb's extrapersonal representation might have resulted from central fatigue-related mechanisms altering the cognitive processes responsible for converting kinesthetic signals into extrapersonal coordinates.
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Affiliation(s)
| | | | | | | | | | | | - Florian Monjo
- Université Côte d’Azur, LAMHESS, France
- Université Savoie Mont Blanc, Interuniversity Laboratory of Human Movement Sciences, EA 7424, Chambéry, France
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Da Silva F, Monjo F, Gioda J, Blain GM, Piponnier E, Corcelle B, Colson SS. Knee position sense and knee flexor neuromuscular function are similarly altered after two submaximal eccentric bouts. Eur J Appl Physiol 2023; 123:311-323. [PMID: 36273044 DOI: 10.1007/s00421-022-05063-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 09/30/2022] [Indexed: 02/07/2023]
Abstract
PURPOSE This study examined eccentric-induced fatigue effects on knee flexor (KF) neuromuscular function and on knee position sense. This design was repeated across two experimental sessions performed 1 week apart to investigate potential repeated bout effects. METHODS Sixteen participants performed two submaximal bouts of KF unilateral eccentric contractions until reaching a 20% decrease in maximal voluntary isometric contraction force. Knee position sense was evaluated with position-matching tasks in seated and prone positions at 40° and 70° of knee flexion so that KF were either antagonistic or agonistic during the positioning movement. The twitch interpolation technique was used to assess KF neuromuscular fatigue. Perceived muscle soreness was also assessed. Measurements were performed before, immediately (POST) and 24 h after (POST24) each eccentric bout. RESULTS No repeated bout effect on neuromuscular function and proprioceptive parameters was observed. At POST, central and peripheral factors contributed to the force decrement as shown by significant decreases in voluntary activation level (- 3.8 ± 4.8%, p < 0.01) and potentiated doublet torque at 100 Hz (- 10 ± 15.8%, p < 0.01). At this time point, position-matching errors significantly increased by 1.7 ± 1.9° in seated position at 40° (p < 0.01). At POST24, in presence of muscle soreness (p < 0.05), although KF neuromuscular function had recovered, position-matching errors increased by 0.6 ± 2.6° in prone position at 40° (p < 0.01). CONCLUSION These results provide evidence that eccentric-induced position sense alterations may arise from central and/or peripheral mechanisms depending on the testing position.
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Affiliation(s)
- Flavio Da Silva
- Laboratoire Motricité Humaine Expertise Sport Santé (UPR 6312), Ecole Universitaire de Recherche HEALTHY: Ecosystèmes des Sciences de la Santé, Université Côte d'Azur, Campus STAPS-Sciences du Sport, 261, Boulevard du Mercantour, 06205, Nice Cedex 03, France.
| | - Florian Monjo
- Laboratoire Motricité Humaine Expertise Sport Santé (UPR 6312), Ecole Universitaire de Recherche HEALTHY: Ecosystèmes des Sciences de la Santé, Université Côte d'Azur, Campus STAPS-Sciences du Sport, 261, Boulevard du Mercantour, 06205, Nice Cedex 03, France
| | - Jennifer Gioda
- Laboratoire Motricité Humaine Expertise Sport Santé (UPR 6312), Ecole Universitaire de Recherche HEALTHY: Ecosystèmes des Sciences de la Santé, Université Côte d'Azur, Campus STAPS-Sciences du Sport, 261, Boulevard du Mercantour, 06205, Nice Cedex 03, France
| | - Gregory M Blain
- Laboratoire Motricité Humaine Expertise Sport Santé (UPR 6312), Ecole Universitaire de Recherche HEALTHY: Ecosystèmes des Sciences de la Santé, Université Côte d'Azur, Campus STAPS-Sciences du Sport, 261, Boulevard du Mercantour, 06205, Nice Cedex 03, France
| | - Enzo Piponnier
- Laboratoire Motricité Humaine Expertise Sport Santé (UPR 6312), Ecole Universitaire de Recherche HEALTHY: Ecosystèmes des Sciences de la Santé, Université Côte d'Azur, Campus STAPS-Sciences du Sport, 261, Boulevard du Mercantour, 06205, Nice Cedex 03, France
| | - Baptiste Corcelle
- Laboratoire Motricité Humaine Expertise Sport Santé (UPR 6312), Ecole Universitaire de Recherche HEALTHY: Ecosystèmes des Sciences de la Santé, Université Côte d'Azur, Campus STAPS-Sciences du Sport, 261, Boulevard du Mercantour, 06205, Nice Cedex 03, France
| | - Serge S Colson
- Laboratoire Motricité Humaine Expertise Sport Santé (UPR 6312), Ecole Universitaire de Recherche HEALTHY: Ecosystèmes des Sciences de la Santé, Université Côte d'Azur, Campus STAPS-Sciences du Sport, 261, Boulevard du Mercantour, 06205, Nice Cedex 03, France
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Lewis MT, Blain GM, Hart CR, Layec G, Rossman MJ, Park SY, Trinity JD, Gifford JR, Sidhu SK, Weavil JC, Hureau TJ, Jessop JE, Bledsoe AD, Amann M, Richardson RS. Acute high-intensity exercise and skeletal muscle mitochondrial respiratory function: role of metabolic perturbation. Am J Physiol Regul Integr Comp Physiol 2021; 321:R687-R698. [PMID: 34549627 DOI: 10.1152/ajpregu.00158.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Recently it was documented that fatiguing, high-intensity exercise resulted in a significant attenuation in maximal skeletal muscle mitochondrial respiratory capacity, potentially due to the intramuscular metabolic perturbation elicited by such intense exercise. With the utilization of intrathecal fentanyl to attenuate afferent feedback from group III/IV muscle afferents, permitting increased muscle activation and greater intramuscular metabolic disturbance, this study aimed to better elucidate the role of metabolic perturbation on mitochondrial respiratory function. Eight young, healthy males performed high-intensity cycle exercise in control (CTRL) and fentanyl-treated (FENT) conditions. Liquid chromatography-mass spectrometry and high-resolution respirometry were used to assess metabolites and mitochondrial respiratory function, respectively, pre- and postexercise in muscle biopsies from the vastus lateralis. Compared with CTRL, FENT yielded a significantly greater exercise-induced metabolic perturbation (PCr: -67% vs. -82%, Pi: 353% vs. 534%, pH: -0.22 vs. -0.31, lactate: 820% vs. 1,160%). Somewhat surprisingly, despite this greater metabolic perturbation in FENT compared with CTRL, with the only exception of respiratory control ratio (RCR) (-3% and -36%) for which the impact of FENT was significantly greater, the degree of attenuated mitochondrial respiratory capacity postexercise was not different between CTRL and FENT, respectively, as assessed by maximal respiratory flux through complex I (-15% and -33%), complex II (-36% and -23%), complex I + II (-31% and -20%), and state 3CI+CII control ratio (-24% and -39%). Although a basement effect cannot be ruled out, this failure of an augmented metabolic perturbation to extensively further attenuate mitochondrial function questions the direct role of high-intensity exercise-induced metabolite accumulation in this postexercise response.
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Affiliation(s)
- Matthew T Lewis
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Gregory M Blain
- LAMHESS, University Nice Sophia Antipolis, Nice, France.,LAMHESS, University of Toulon, La Garde, France
| | - Corey R Hart
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Gwenael Layec
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Matthew J Rossman
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Song-Young Park
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah.,School of Health and Kinesiology, University of Nebraska, Omaha, Nebraska
| | - Joel D Trinity
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Jayson R Gifford
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Simranjit K Sidhu
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah.,Discipline of Physiology, School of Medicine, University of Adelaide, Adelaide, South Australia, Australia
| | - Joshua C Weavil
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Thomas J Hureau
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah.,LAMHESS, University Nice Sophia Antipolis, Nice, France.,LAMHESS, University of Toulon, La Garde, France
| | - Jacob E Jessop
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Amber D Bledsoe
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Markus Amann
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah.,Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Russell S Richardson
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
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Abstract
INTRODUCTION We determined the recovery from neuromuscular fatigue in six professional (PRO) and seven moderately trained (MOD) cyclists after repeated cycling time trials of various intensities/durations. METHOD Participants performed two 1-min (1minTT) or two 10-min (10minTT) self-paced cycling time trials with 5 min of recovery in between. Central and peripheral fatigue were quantified via preexercise to postexercise (15-s through 15-min recovery) changes in voluntary activation (VA) and potentiated twitch force. VA was measured using the interpolated twitch technique, and potentiated twitch force was evoked by single (QTsingle) and paired (10-Hz (QT10) and 100-Hz (QT100)) electrical stimulations of the femoral nerve. RESULTS Mean power output was 32%-72% higher during all the time trials and decreased less (-10% vs -13%) from the first to second time trial in PRO compared with MOD (P < 0.05). Conversely, exercise-induced reduction in QTsingle and QT10/QT100 was significantly lower in PRO after every time trial (P < 0.05). Recovery from fatigue from 15 s to 2 min for QTsingle and QT10/QT100 was slower in PRO after every time trial (P < 0.05). In both groups, the reduction in QTsingle was lower after the 10minTTs compared with 1minTTs (P < 0.05). Conversely, VA decreased more after the 10minTTs compared with 1minTTs (P < 0.05). CONCLUSION Our findings showed that excitation-contraction coupling was preserved after exercise in PRO compared with MOD. This likely contributed to the improved performance during repeated cycling time trials of various intensity/duration in PRO, despite a slower rate of recovery in its early phase. Finally, the time course of recovery from neuromuscular fatigue in PRO was dependent on the effects of prolonged low-frequency force depression.
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Layec G, Blain GM, Rossman MJ, Park SY, Hart CR, Trinity JD, Gifford JR, Sidhu SK, Weavil JC, Hureau TJ, Amann M, Richardson RS. Acute High-Intensity Exercise Impairs Skeletal Muscle Respiratory Capacity. Med Sci Sports Exerc 2019; 50:2409-2417. [PMID: 30102675 DOI: 10.1249/mss.0000000000001735] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PURPOSE The effect of an acute bout of exercise, especially high-intensity exercise, on the function of mitochondrial respiratory complexes is not well understood, with potential implications for both the healthy population and patients undergoing exercise-based rehabilitation. Therefore, this study sought to comprehensively examine respiratory flux through the different complexes of the electron transport chain in skeletal muscle mitochondria before and immediately after high-intensity aerobic exercise. METHODS Muscle biopsies of the vastus lateralis were obtained at baseline and immediately after a 5-km time trial performed on a cycle ergometer. Mitochondrial respiratory flux through the complexes of the electron transport chain was measured in permeabilized skeletal muscle fibers by high-resolution respirometry. RESULTS Complex I + II state 3 (state 3CI + CII) respiration, a measure of oxidative phosphorylation capacity, was diminished immediately after the exercise (pre, 27 ± 3 ρm·mg·s; post, 17 ± 2 ρm·mg·s; P < 0.05). This decreased oxidative phosphorylation capacity was predominantly the consequence of attenuated complex II-driven state 3 (state 3CII) respiration (pre, 17 ± 1 ρm·mg·s; post, 9 ± 2 ρm·mg·s; P < 0.05). Although complex I-driven state 3 (3CI) respiration was also lower (pre, 20 ± 2 ρm·mg·s; post, 14 ± 4 ρm·mg·s), this did not reach statistical significance (P = 0.27). In contrast, citrate synthase activity, proton leak (state 2 respiration), and complex IV capacity were not significantly altered immediately after the exercise. CONCLUSIONS These findings reveal that acute high-intensity aerobic exercise significantly inhibits skeletal muscle state 3CII and oxidative phosphorylation capacity. This, likely transient, mitochondrial defect might amplify the exercise-induced development of fatigue and play an important role in initiating exercise-induced mitochondrial adaptations.
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Affiliation(s)
- Gwenael Layec
- Department of Medicine, University of Utah, Salt Lake City, UT.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT.,Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT
| | | | - Matthew J Rossman
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT
| | - Song Y Park
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT
| | - Corey R Hart
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT
| | - Joel D Trinity
- Department of Medicine, University of Utah, Salt Lake City, UT.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT.,Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT
| | - Jayson R Gifford
- Department of Medicine, University of Utah, Salt Lake City, UT.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT.,Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT
| | - Simranjit K Sidhu
- Department of Medicine, University of Utah, Salt Lake City, UT.,Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, AUSTRALIA
| | - Joshua C Weavil
- Department of Medicine, University of Utah, Salt Lake City, UT
| | - Thomas J Hureau
- Department of Medicine, University of Utah, Salt Lake City, UT.,Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT.,Mitochondria, Oxidative Stress and Muscular Protection Laboratory, EA 3072, University of Strasbourg, Strasbourg, FRANCE
| | - Markus Amann
- Department of Medicine, University of Utah, Salt Lake City, UT.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT.,Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT
| | - Russell S Richardson
- Department of Medicine, University of Utah, Salt Lake City, UT.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT.,Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT
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Blain GM, Mangum TS, Sidhu SK, Weavil JC, Hureau TJ, Jessop JE, Bledsoe AD, Richardson RS, Amann M. Group III/IV muscle afferents limit the intramuscular metabolic perturbation during whole body exercise in humans. J Physiol 2016; 594:5303-15. [PMID: 27241818 DOI: 10.1113/jp272283] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 05/16/2016] [Indexed: 12/27/2022] Open
Abstract
KEY POINTS The purpose of this study was to determine the role of group III/IV muscle afferents in limiting the endurance exercise-induced metabolic perturbation assayed in muscle biopsy samples taken from locomotor muscle. Lumbar intrathecal fentanyl was used to attenuate the central projection of μ-opioid receptor-sensitive locomotor muscle afferents during a 5 km cycling time trial. The findings suggest that the central projection of group III/IV muscle afferent feedback constrains voluntary neural 'drive' to working locomotor muscle and limits the exercise-induced intramuscular metabolic perturbation. Therefore, the CNS might regulate the degree of metabolic perturbation within locomotor muscle and thereby limit peripheral fatigue. It appears that the group III/IV muscle afferents are an important neural link in this regulatory mechanism, which probably serves to protect locomotor muscle from the potentially severe functional impairment as a consequence of severe intramuscular metabolic disturbance. ABSTRACT To investigate the role of metabo- and mechanosensitive group III/IV muscle afferents in limiting the intramuscular metabolic perturbation during whole body endurance exercise, eight subjects performed 5 km cycling time trials under control conditions (CTRL) and with lumbar intrathecal fentanyl impairing lower limb muscle afferent feedback (FENT). Vastus lateralis muscle biopsies were obtained before and immediately after exercise. Motoneuronal output was estimated through vastus lateralis surface electromyography (EMG). Exercise-induced changes in intramuscular metabolites were determined using liquid and gas chromatography-mass spectrometry. Quadriceps fatigue was quantified by pre- to post-exercise changes in potentiated quadriceps twitch torque (ΔQTsingle ) evoked by electrical femoral nerve stimulation. Although motoneuronal output was 21 ± 12% higher during FENT compared to CTRL (P < 0.05), time to complete the time trial was similar (∼8.8 min). Compared to CTRL, power output during FENT was 10 ± 4% higher in the first half of the time trial, but 11 ± 5% lower in the second half (both P < 0.01). The exercise-induced increase in intramuscular inorganic phosphate, H(+) , adenosine diphosphate, lactate and phosphocreatine depletion was 55 ± 30, 62 ± 18, 129 ± 63, 47 ± 14 (P < 0.001) and 27 ± 14% (P < 0.01) greater in FENT than CTRL. ΔQTsingle was greater following FENT than CTRL (-52 ± 2 vs -31 ± 1%, P < 0.001) and this difference was positively correlated with the difference in inorganic phosphate (r(2) = 0.79; P < 0.01) and H(+) (r(2) = 0.92; P < 0.01). In conclusion, during whole body exercise, group III/IV muscle afferents provide feedback to the CNS which, in turn, constrains motoneuronal output to the active skeletal muscle. This regulatory mechanism limits the exercise-induced intramuscular metabolic perturbation, preventing an abnormal homeostatic challenge and excessive peripheral fatigue.
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Affiliation(s)
- Gregory M Blain
- LAMHESS, EA 6312, University Nice Sophia Antipolis, University of Toulon, Nice, France.
| | - Tyler S Mangum
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA
| | - Simranjit K Sidhu
- Department of Medicine, University of Utah, Salt Lake City, UT, USA.,Discipline of Physiology, School of Medicine, The University of Adelaide, Australia
| | - Joshua C Weavil
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA
| | - Thomas J Hureau
- LAMHESS, EA 6312, University Nice Sophia Antipolis, University of Toulon, Nice, France.,Department of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Jacob E Jessop
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Amber D Bledsoe
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Russell S Richardson
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA.,Department of Medicine, University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education, and Clinical Centre, Salt Lake City VAMC, UT, USA
| | - Markus Amann
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA.,Department of Medicine, University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education, and Clinical Centre, Salt Lake City VAMC, UT, USA.,Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
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Hureau TJ, Ducrocq GP, Blain GM. Peripheral And Central Fatigue Development And Short-term Recovery During All-out Repeated Sprints. Med Sci Sports Exerc 2015. [DOI: 10.1249/01.mss.0000477313.87170.41] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Blain GM, Mangum TS, Sidhu SK, Weavil JC, Richardson RS, Hureau TJ, Jessop JE, Bledsoe AD, Amann M. Group III/IV Muscle Afferents Restrict Intramuscular Metabolic Perturbation In Exercising Humans. Med Sci Sports Exerc 2015. [DOI: 10.1249/01.mss.0000477316.10042.43] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hureau TJ, Olivier N, Millet GY, Meste O, Blain GM. Exercise performance is regulated during repeated sprints to limit the development of peripheral fatigue beyond a critical threshold. Exp Physiol 2014; 99:951-63. [PMID: 24728680 DOI: 10.1113/expphysiol.2014.077974] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We hypothesized that exercise performance is adjusted during repeated sprints in order not to surpass a critical threshold of peripheral fatigue. Twelve men randomly performed three experimental sessions on different days, i.e. one single 10 s all-out sprint and two trials of 10 × 10 s all-out sprints with 30 s of passive recovery in between. One trial was performed in the unfatigued state (CTRL) and one following electrically induced quadriceps muscle fatigue (FTNMES). Peripheral fatigue was quantified by comparing pre- with postexercise changes in potentiated quadriceps twitch force (ΔQtw-pot) evoked by supramaximal magnetic stimulation of the femoral nerve. Central fatigue was estimated by comparing pre- with postexercise voluntary activation of quadriceps motor units. The root mean square (RMS) of the vastus lateralis and vastus medialis EMG normalized to maximal M-wave amplitude (RMS.Mmax (-1)) was also calculated during sprints. Compared with CTRL condition, pre-existing quadriceps muscle fatigue in FTNMES (ΔQtw-pot = -29 ± 4%) resulted in a significant (P < 0.05) reduction in power output (-4.0 ± 0.9%) associated with a reduction in RMS.Mmax (-1). However, ΔQtw-pot postsprints decreased by 51% in both conditions, indicating that the level of peripheral fatigue was identical and independent of the degree of pre-existing fatigue. Our findings show that power output and cycling EMG are adjusted during exercise in order to limit the development of peripheral fatigue beyond a constant threshold. We hypothesize that the contribution of peripheral fatigue to exercise limitation involves a reduction in central motor drive in addition to the impairment in muscular function.
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Affiliation(s)
- Thomas J Hureau
- University of Nice Sophia Antipolis, Toulon, LAMHESS, EA 6309, F-06205, Nice, France University of Lille Nord de France, F-59000, Lille, France; UDSL, EA 4488, F-59790, Ronchin, France
| | - Nicolas Olivier
- University of Lille Nord de France, F-59000, Lille, France; UDSL, EA 4488, F-59790, Ronchin, France
| | - Guillaume Y Millet
- University of Lyon, F-42023, Saint Etienne, France University of Calgary, Faculty of Kinesiology, Human Performance Laboratory, Calgary, Alberta, Canada
| | - Olivier Meste
- CNRS - University of Nice Sophia Antipolis, I3S, F-06900, Sophia Antipolis, France
| | - Gregory M Blain
- University of Nice Sophia Antipolis, Toulon, LAMHESS, EA 6309, F-06205, Nice, France University of Lille Nord de France, F-59000, Lille, France; UDSL, EA 4488, F-59790, Ronchin, France
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Dempsey JA, Powell FL, Bisgard GE, Blain GM, Poulin MJ, Smith CA. Role of chemoreception in cardiorespiratory acclimatization to, and deacclimatization from, hypoxia. J Appl Physiol (1985) 2013; 116:858-66. [PMID: 24371017 DOI: 10.1152/japplphysiol.01126.2013] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
During sojourn to high altitudes, progressive time-dependent increases occur in ventilation and in sympathetic nerve activity over several days, and these increases persist upon acute restoration of normoxia. We discuss evidence concerning potential mediators of these changes, including the following: 1) correction of alkalinity in cerebrospinal fluid; 2) increased sensitivity of carotid chemoreceptors; and 3) augmented translation of carotid chemoreceptor input (at the level of the central nervous system) into increased respiratory motor output via sensitization of hypoxic sensitive neurons in the central nervous system and/or an interdependence of central chemoreceptor responsiveness on peripheral chemoreceptor sensory input. The pros and cons of chemoreceptor sensitization and cardiorespiratory acclimatization to hypoxia and intermittent hypoxemia are also discussed in terms of their influences on arterial oxygenation, the work of breathing, sympathoexcitation, systemic blood pressure, and exercise performance. We propose that these adaptive processes may have negative implications for the cardiovascular health of patients with sleep apnea and perhaps even for athletes undergoing regimens of "sleep high-train low"!
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Abstract
AIM Conduit artery function in obese humans is frequently assessed at rest, but very little is known about resistance artery function in response to muscle contraction. We tested the hypothesis that obese adults will exhibit reduced contraction-induced rapid onset vasodilatation. Single and brief forearm contractions were used to isolate the local effects of muscle contraction on the forearm vasodilatory response, independent of systemic haemodynamic and sympathetic neural influence. METHODS We measured forearm blood flow (Doppler ultrasound), blood pressure (finger photoplethysmography) and heart rate (electrocardiogram) on a beat-by-beat basis in 14 obese (body mass index = 36.2 ± 1.7 kg m(-2)) and 14 lean (body mass index = 21.6 ± 0.7 kg m(-2)) young (18-40 years) adults. Percent changes from baseline in forearm vascular conductance (FVC(%) ) were calculated in response to single, brief forearm contractions performed in random order at 15, 20, 25, 30, 40 and 50% of maximal voluntary contraction (MVC). RESULTS In both groups, each single contraction evoked a significant (P < 0.05), immediate (within one cardiac cycle) and graded FVC(%) increase from one up to six cardiac cycles post-contraction. Immediate (20-50% MVC), peak (15-50% MVC) and total (area under the curve, 20-50% MVC) vasodilatory responses were reduced with obesity. The degree of impaired vasodilatation increased with increasing workloads. CONCLUSIONS These novel findings demonstrate a blunted contraction-induced rapid onset vasodilatation with obesity that is exercise intensity dependent. Impaired rapid onset vasodilatation may negatively impact haemodynamic responses to everyday intermittent activities performed by obese humans.
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Affiliation(s)
- G M Blain
- Department of Population Health Sciences, The John Rankin Laboratory of Pulmonary Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, USA
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Dempsey JA, Smith CA, Blain GM, Xie A, Gong Y, Teodorescu M. Role of Central/Peripheral Chemoreceptors and Their Interdependence in the Pathophysiology of Sleep Apnea. Advances in Experimental Medicine and Biology 2012; 758:343-9. [DOI: 10.1007/978-94-007-4584-1_46] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Amann M, Blain GM, Proctor LT, Sebranek JJ, Pegelow DF, Dempsey JA. Implications of group III and IV muscle afferents for high-intensity endurance exercise performance in humans. J Physiol 2011; 589:5299-309. [PMID: 21878520 DOI: 10.1113/jphysiol.2011.213769] [Citation(s) in RCA: 190] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
We investigated the influence of group III/IV muscle afferents on peripheral fatigue, central motor drive (CMD) and endurance capacity during high-intensity leg-cycling. In a double-blind, placebo-controlled design, seven males performed constant-load cycling exercise (318 ± 9 W; 80% of peak power output (W(peak))) to exhaustion under placebo conditions and with lumbar intrathecal fentanyl impairing spinal μ-opioid receptor-sensitive group III/IV muscle afferents. Peripheral fatigue was assessed via changes in pre- vs. post-exercise quadriceps force in response to supramaximal magnetic femoral nerve stimulation (ΔQ(tw,pot)). CMD was estimated via quadriceps electromyogram. To rule out a direct central effect of fentanyl, we documented unchanged resting cardioventilatory responses. Compared to placebo, significant hypoventilation during the fentanyl trial was indicated by the 9% lower V(E)/V(CO(2)), causing a 5 mmHg increase in end-tidal P(CO(2)) and a 3% lower haemoglobin saturation. Arterial pressure and heart rate averaged 8 and 10% lower, respectively, during the fentanyl trial and these differences progressively diminished towards end-exercise. Although initially similar, the percent change in CMD was 9 ± 3% higher at end-exercise with fentanyl vs. placebo (P < 0.05). Time to exhaustion was shorter (6.8 ± 0.3 min vs. 8.7 ± 0.3 min) and end-exercise ΔQ(tw,pot) was about one-third greater (-44 ± 2% vs. -34 ± 2%) following fentanyl vs. placebo. The rate of peripheral fatigue development was 67 ± 10% greater during the fentanyl trial (P < 0.01). Our findings suggest that feedback from group III/IV muscle afferents limits CMD but also minimizes locomotor muscle fatigue development by stimulating adequate ventilatory and circulatory responses to exercise. In the face of blocked group III/IV muscle afferents, CMD is less inhibited but O(2) transport compromised and locomotor muscle fatigability is exacerbated with a combined net effect of a reduced endurance performance.
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Affiliation(s)
- Markus Amann
- University of Utah, Department of Internal Medicine, Salt Lake City, UT, USA.
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Limberg JK, Evans TD, Blain GM, Pegelow DF, Danielson JR, Eldridge MW, Proctor LT, Sebranek JJ, Schrage WG. Effect of obesity and metabolic syndrome on hypoxic vasodilation. Eur J Appl Physiol 2011; 112:699-709. [PMID: 21656228 DOI: 10.1007/s00421-011-2025-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 05/23/2011] [Indexed: 12/30/2022]
Abstract
This study was designed to test whether obese adults and adults with metabolic syndrome (MetSyn) exhibit altered hyperemic responses to hypoxia at rest and during forearm exercise when compared with lean controls. We hypothesized blood flow responses due to hypoxia would be lower in young obese subjects (n = 11, 24 ± 2 years, BMI 36 ± 2 kg m(-2)) and subjects with MetSyn (n = 8, 29 ± 3 years BMI 39 ± 2 kg m(-2)) when compared with lean adults (n = 13, 29 ± 2 years, BMI 24 ± 1 kg m(-2)). We measured forearm blood flow (FBF, Doppler Ultrasound) and arterial oxygen saturation (pulse oximetry) during rest and steady-state dynamic forearm exercise (20 contractions/min at 8 and 12 kg) under two conditions: normoxia (0.21 F(i)O(2), ~98% S(a)O(2)) and hypoxia (~0.10 F(i)O(2), 80% S(a)O(2)). Forearm vascular conductance (FVC) was calculated as FBF/mean arterial blood pressure. At rest, the percent change in FVC with hypoxia was greater in adults with MetSyn when compared with lean controls (p = 0.02); obese and lean adult responses were not statistically different. Exercise increased FVC from resting levels in all groups (p < 0.05). Hypoxia caused an additional increase in FVC (p < 0.05) that was not different between groups; responses to hypoxia were heterogeneous within and between groups. Reporting FVC responses as absolute or percent changes led to similar conclusions. These results suggest adults with MetSyn exhibit enhanced hypoxic vasodilation at rest. However, hypoxic responses during exercise in obese adults and adults with MetSyn were not statistically different when compared with lean adults. Individual hypoxic vasodilatory responses were variable, suggesting diversity in vascular control.
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Affiliation(s)
- Jacqueline K Limberg
- Department of Kinesiology, School of Education, University of Wisconsin, 1149 Natatorium, Madison, WI 53706, USA.
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Amann M, Blain GM, Proctor LT, Sebranek JJ, Pegelow DF, Dempsey JA. Group III and IV muscle afferents contribute to ventilatory and cardiovascular response to rhythmic exercise in humans. J Appl Physiol (1985) 2010; 109:966-76. [PMID: 20634355 DOI: 10.1152/japplphysiol.00462.2010] [Citation(s) in RCA: 275] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated the role of somatosensory feedback on cardioventilatory responses to rhythmic exercise in five men. In a double-blind, placebo-controlled design, subjects performed the same leg cycling exercise (50/100/150/325 ± 19 W, 3 min each) under placebo conditions (interspinous saline, L(3)-L(4)) and with lumbar intrathecal fentanyl impairing central projection of spinal opioid receptor-sensitive muscle afferents. Quadriceps strength was similar before and after fentanyl administration. To evaluate whether a cephalad migration of fentanyl affected cardioventilatory control centers in the brain stem, we compared resting ventilatory responses to hypercapnia (HCVR) and cardioventilatory responses to arm vs. leg cycling exercise after each injection. Similar HCVR and minor effects of fentanyl on cardioventilatory responses to arm exercise excluded direct medullary effects of fentanyl. Central command during leg exercise was estimated via quadriceps electromyogram. No differences between conditions were found in resting heart rate (HR), ventilation [minute ventilation (VE)], or mean arterial pressure (MAP). Quadriceps electromyogram, O(2) consumption (VO(2)), and plasma lactate were similar in both conditions at the four steady-state workloads. Compared with placebo, a substantial hypoventilation during fentanyl exercise was indicated by the 8-17% reduction in VE/CO(2) production (VCO(2)) secondary to a reduced breathing frequency, leading to average increases of 4-7 Torr in end-tidal PCO(2) (P < 0.001) and a reduced hemoglobin saturation (-3 ± 1%; P < 0.05) at the heaviest workload (∼90% maximal VO(2)) with fentanyl. HR was reduced 2-8%, MAP 8-13%, and ratings of perceived exertion by 13% during fentanyl vs. placebo exercise (P < 0.05). These findings demonstrate the essential contribution of muscle afferent feedback to the ventilatory, cardiovascular, and perceptual responses to rhythmic exercise in humans, even in the presence of unaltered contributions from other major inputs to cardioventilatory control.
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Affiliation(s)
- Markus Amann
- John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin, Madison, Wisconsin, USA.
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Blain GM, Smith CA, Henderson KS, Dempsey JA. Peripheral chemoreceptors determine the respiratory sensitivity of central chemoreceptors to CO(2). J Physiol 2010; 588:2455-71. [PMID: 20421288 DOI: 10.1113/jphysiol.2010.187211] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
We assessed the contribution of carotid body chemoreceptors to the ventilatory response to specific CNS hypercapnia in eight unanaesthetized, awake dogs. We denervated one carotid body (CB) and used extracorporeal blood perfusion of the reversibly isolated remaining CB to maintain normal CB blood gases (normoxic, normocapnic perfusate), to inhibit (hyperoxic, hypocapnic perfusate) or to stimulate (hypoxic, normocapnic perfusate) the CB chemoreflex, while the systemic circulation, and therefore the CNS and central chemoreceptors, were exposed consecutively to four progressive levels of systemic arterial hypercapnia via increased fractional inspired CO(2) for 7 min at each level. Neither unilateral CB denervation nor CB perfusion, per se, affected breathing. Relative to CB control conditions (normoxic, normocapnic perfusion), we found that CB chemoreflex inhibition decreased the slope of the ventilatory response to CNS hypercapnia in all dogs to an average of 19% of control values (range 0-38%; n = 6), whereas CB chemoreflex stimulation increased the slope of the ventilatory response to CNS hypercapnia in all dogs to an average of 223% of control values (range 204-235%; n = 4). We conclude that the gain of the CNS CO(2)/H(+) chemoreceptors in dogs is critically dependent on CB afferent activity and that CNS-CB interaction results in hyperadditive ventilatory responses to central hypercapnia.
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Affiliation(s)
- Gregory M Blain
- The John Rankin Laboratory of Pulmonary Medicine, Department of Population Health Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA.
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Abstract
Exercise is a common nonpharmacological way to combat obesity; however, no studies have systematically tested whether obese humans exhibit reduced skeletal muscle blood flow during dynamic exercise. We hypothesized that exercise-induced blood flow to skeletal muscle would be lower in young healthy obese subjects (body mass index of >30 kg/m(2)) compared with lean subjects (body mass index of <25 kg/m(2)). We measured blood flow (Doppler Ultrasound of the brachial and femoral arteries), blood pressure (auscultation, Finapress), and heart rate (ECG) during rest and two forms of single-limb, steady-state dynamic exercise: forearm exercise (20 contractions/min at 4, 8, and 12 kg) and leg exercise (40 kicks/min at 7 and 14 W). Forearm exercise increased forearm blood flow (FBF) similarly in both groups (P > 0.05; obese subjects n = 9, lean subjects n = 9). When FBF was normalized for perfusion pressure, forearm vascular conductance was not different between groups at increasing workloads (P > 0.05). Leg exercise increased leg blood flow (LBF) similarly in both groups (P > 0.05; obese subjects n = 10, lean subjects n = 12). When LBF was normalized for perfusion pressure, leg vascular conductance was not different between groups at increasing workloads (P > 0.05). These results were confirmed when relative blood flow was expressed at average relative workloads. In conclusion, our results show that obese subjects exhibited preserved FBF and LBF during dynamic exercise.
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Affiliation(s)
- Jacqueline K Limberg
- Dept. of Kinesiology, School of Education, Univ. of Wisconsin, Madison, WI 53706, USA
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Limberg JK, Devita MD, Blain GM, Schrage WG. Exercise In Obesity: Impaired Muscle Blood Flow. Med Sci Sports Exerc 2009. [DOI: 10.1249/01.mss.0000353415.23857.50] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Blain GM, Smith CA, Henderson KS, Demspey JA. Contribution of carotid body chemoreceptors to the eupneic drive to breathe in the intact awake canine. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.957.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Gregory M Blain
- Population Health SciencesUniversity of Wisconsin ‐ MadisonMadisonWI
| | - Curtis A Smith
- Population Health SciencesUniversity of Wisconsin ‐ MadisonMadisonWI
| | | | - Jerome A Demspey
- Population Health SciencesUniversity of Wisconsin ‐ MadisonMadisonWI
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