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Keeler JM, Greenshields JT, Goss CS, Baker TB, Chapman RF, Johnson BD, Schlader ZJ. Acute moderate normobaric hypoxia does not modify circulating thyroid hormone concentrations induced by 1 h of head-out cold-water immersion. J Appl Physiol (1985) 2024; 136:1400-1409. [PMID: 38660723 DOI: 10.1152/japplphysiol.00061.2024] [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: 01/22/2024] [Revised: 04/15/2024] [Accepted: 04/15/2024] [Indexed: 04/26/2024] Open
Abstract
This study tested the hypothesis that acute moderate normobaric hypoxia augments circulating thyroid hormone concentrations during and following 1 h of cold head-out water immersion (HOWI), compared with when cold HOWI is completed during normobaric normoxia. In a randomized crossover single-blind design, 12 healthy adults (27 ± 2 yr, 2 women) completed 1 h of cold (22.0 ± 0.1°C) HOWI breathing either normobaric normoxia ([Formula: see text] = 0.21) or normobaric hypoxia ([Formula: see text] = 0.14). Free and total thyroxine (T3) and triiodothyronine (T4), and thyroid-stimulating hormone (TSH) concentrations were measured in venous blood samples obtained before (baseline), during (15-, 30-, and 60 min), and 15 min following HOWI (post-), and were corrected for changes in plasma volume. Arterial oxyhemoglobin saturation and core (rectal) temperature were measured continuously. Arterial oxyhemoglobin saturation was lower during hypoxia (90 ± 3%) compared with normoxia (98 ± 1%, P < 0.001). Core temperature fell from baseline (normoxia: 37.2 ± 0.4°C, hypoxia: 37.2 ± 0.4°C) to post-cold HOWI (normoxia: 36.4 ± 0.5°C, hypoxia: 36.3 ± 0.5°C, P < 0.001) in both conditions but did not change differently between conditions (condition × time: P = 0.552). Circulating TSH, total T3, free T4, total T3, and free T4 concentrations demonstrated significant main effects of time (all P ≤ 0.024), but these changes did not differ between normoxic and hypoxic conditions (condition × time: all P ≥ 0.163). These data indicate that acute moderate normobaric hypoxia does not modify the circulating thyroid hormone response during 1 h of cold HOWI.NEW & NOTEWORTHY Acute head-out cold (22°C) water immersion (HOWI) decreased core temperature and increased thermogenesis. This thermogenic response was paralleled by the activation of the hypothalamic-pituitary-thyroid axis, as evidenced by changes in thyroid hormones. However, cold HOWI in combination with moderate normobaric hypoxia did not modify the thermogenic nor the circulating thyroid hormone response. This finding suggests that hypoxia-induced alterations in thyroid hormone concentrations are unlikely to acutely contribute to adaptations resulting from repeated cold-water exposures.
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Affiliation(s)
- Jason M Keeler
- Department of Kinesiology, Indiana University School of Public Health-Bloomington, Bloomington, Indiana, United States
| | - Joel T Greenshields
- Department of Kinesiology, Indiana University School of Public Health-Bloomington, Bloomington, Indiana, United States
| | - Curtis S Goss
- Department of Kinesiology, Indiana University School of Public Health-Bloomington, Bloomington, Indiana, United States
| | - Tyler B Baker
- Department of Kinesiology, Indiana University School of Public Health-Bloomington, Bloomington, Indiana, United States
| | - Robert F Chapman
- Department of Kinesiology, Indiana University School of Public Health-Bloomington, Bloomington, Indiana, United States
| | - Blair D Johnson
- Department of Kinesiology, Indiana University School of Public Health-Bloomington, Bloomington, Indiana, United States
| | - Zachary J Schlader
- Department of Kinesiology, Indiana University School of Public Health-Bloomington, Bloomington, Indiana, United States
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Brutsaert TD, Harman TS, Bigham AW, Kalker A, Jorgensen KC, Zhu KT, Steiner BC, Hawkins E, Day TA, Kunwar AJ, Thakur N, Dhungel S, Sherpa N, Holmström PK. Larger spleens and greater splenic contraction during exercise may be an adaptive characteristic of Nepali Sherpa at high-altitude. Am J Hum Biol 2024:e24090. [PMID: 38741522 DOI: 10.1002/ajhb.24090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 04/26/2024] [Accepted: 04/29/2024] [Indexed: 05/16/2024] Open
Abstract
OBJECTIVES The Sherpa ethnic group living at altitude in Nepal may have experienced natural selection in response to chronic hypoxia. We have previously shown that Sherpa in Kathmandu (1400 m) possess larger spleens and a greater apnea-induced splenic contraction compared to lowland Nepalis. This may be significant for exercise capacity at altitude as the human spleen responds to stress-induced catecholamine secretion by an immediate contraction, which results in transiently elevated hemoglobin concentration ([Hb]). METHODS To investigate splenic contraction in response to exercise at high-altitude (4300 m; Pb = ~450 Torr), we recruited 63 acclimatized Sherpa (29F) and 14 Nepali non-Sherpa (7F). Spleen volume was measured before and after maximal exercise on a cycle ergometer by ultrasonography, along with [Hb] and oxygen saturation (SpO2). RESULTS Resting spleen volume was larger in the Sherpa compared with Nepali non-Sherpa (237 ± 62 vs. 165 ± 34 mL, p < .001), as was the exercise-induced splenic contraction (Δspleen volume, 91 ± 40 vs. 38 ± 32 mL, p < .001). From rest to exercise, [Hb] increased (1.2 to 1.4 g.dl-1), SpO2 decreased (~9%) and calculated arterial oxygen content (CaO2) remained stable, but there were no significant differences between groups. In Sherpa, both resting spleen volume and the Δspleen volume were modest positive predictors of the change (Δ) in [Hb] and CaO2 with exercise (p-values from .026 to .037 and R2 values from 0.059 to 0.067 for the predictor variable). CONCLUSIONS Larger spleens and greater splenic contraction may be an adaptive characteristic of Nepali Sherpa to increase CaO2 during exercise at altitude, but the direct link between spleen size/function and hypoxia tolerance remains unclear.
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Affiliation(s)
- Tom D Brutsaert
- Department of Exercise Science, Syracuse University, Syracuse, NY, USA
| | | | - Abigail W Bigham
- Department of Anthropology, University of California, Los Angeles, CA, USA
| | - Anne Kalker
- Department of Anesthesiology, Raboud Medical Center, Nijmegen, Netherlands
| | - Kelsey C Jorgensen
- Department of Anthropology, University of California, Los Angeles, CA, USA
| | - Kimberly T Zhu
- Department of Anthropology, University of California, Los Angeles, CA, USA
| | - Bethany C Steiner
- Department of Exercise Science, Syracuse University, Syracuse, NY, USA
| | - Ella Hawkins
- Department of Anthropology, Syracuse University, Syracuse, NY, USA
| | - Trevor A Day
- Department of Biology, Mount Royal University, Calgary, Canada
| | - Ajaya J Kunwar
- Kathmandu Center for Genomics and Research Laboratory, Global Hospital, Gwarko, Nepal
| | - Nilam Thakur
- Kathmandu Center for Genomics and Research Laboratory, Global Hospital, Gwarko, Nepal
| | - Sunil Dhungel
- College of Medicine, Nepalese Army Institute of Health Sciences, Kathmandu, Nepal
| | - Nima Sherpa
- Local collaborator without institutional affiliation
| | - Pontus K Holmström
- Department of Exercise Science, Syracuse University, Syracuse, NY, USA
- Department of Health Sciences, Mid-Sweden University, Östersund, Sweden
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Kjeld T, Krag TO, Brenøe A, Møller AM, Arendrup HC, Højberg J, Fuglø D, Hancke S, Tolbod LP, Gormsen LC, Vissing J, Hansen EG. Hemoglobin concentration and blood shift during dry static apnea in elite breath hold divers. Front Physiol 2024; 15:1305171. [PMID: 38745836 PMCID: PMC11092981 DOI: 10.3389/fphys.2024.1305171] [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: 09/30/2023] [Accepted: 01/23/2024] [Indexed: 05/16/2024] Open
Abstract
Introduction Elite breath-hold divers (BHD) enduring apneas of more than 5 min are characterized by tolerance to arterial blood oxygen levels of 4.3 kPa and low oxygen-consumption in their hearts and skeletal muscles, similar to adult seals. Adult seals possess an adaptive higher hemoglobin-concentration and Bohr effect than pups, and when sedated, adult seals demonstrate a blood shift from the spleen towards the brain, lungs, and heart during apnea. We hypothesized these observations to be similar in human BHD. Therefore, we measured hemoglobin- and 2,3-biphosphoglycerate-concentrations in BHD (n = 11) and matched controls (n = 11) at rest, while myocardial mass, spleen and lower extremity volumes were assessed at rest and during apnea in BHD. Methods and results After 4 min of apnea, left ventricular myocardial mass (LVMM) determined by 15O-H2O-PET/CT (n = 6) and cardiac MRI (n = 6), was unaltered compared to rest. During maximum apnea (∼6 min), lower extremity volume assessed by DXA-scan revealed a ∼268 mL decrease, and spleen volume, assessed by ultrasonography, decreased ∼102 mL. Compared to age, BMI and VO2max matched controls (n = 11), BHD had similar spleen sizes and 2,3- biphosphoglycerate-concentrations, but higher total hemoglobin-concentrations. Conclusion Our results indicate: 1) Apnea training in BHD may increase hemoglobin concentration as an oxygen conserving adaptation similar to adult diving mammals. 2) The blood shift during dry apnea in BHD is 162% more from the lower extremities than from the spleen. 3) In contrast to the previous theory of the blood shift demonstrated in sedated adult seals, blood shift is not towards the heart during dry apnea in humans.
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Affiliation(s)
- Thomas Kjeld
- Copenhagen Neuromuscular Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Thomas O. Krag
- Copenhagen Neuromuscular Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Anders Brenøe
- Department of Clinical Medicine, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Ann Merete Møller
- Department of Anesthesiology, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
| | | | - Jens Højberg
- Department of Cardiothoracic Anesthesiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Dan Fuglø
- Department of Nuclear Medicine, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Søren Hancke
- Department of Clinical Medicine, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Lars Poulsen Tolbod
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, Aarhus, Denmark
| | - Lars Christian Gormsen
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, Aarhus, Denmark
| | - John Vissing
- Copenhagen Neuromuscular Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Egon Godthaab Hansen
- Department of Anesthesiology, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
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Holmström PK, Harman TS, Kalker A, Steiner B, Hawkins E, Jorgensen KC, Zhu KT, Kunwar AJ, Thakur N, Dhungel S, Sherpa N, Day TA, Schagatay EK, Bigham AW, Brutsaert TD. Differential splenic responses to hyperoxic breathing at high altitude in Sherpa and lowlanders. Exp Physiol 2024; 109:535-548. [PMID: 38180087 PMCID: PMC10988702 DOI: 10.1113/ep091579] [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: 10/09/2023] [Accepted: 12/12/2023] [Indexed: 01/06/2024]
Abstract
The human spleen contracts in response to stress-induced catecholamine secretion, resulting in a temporary rise in haemoglobin concentration ([Hb]). Recent findings highlighted enhanced splenic response to exercise at high altitude in Sherpa, possibly due to a blunted splenic response to hypoxia. To explore the potential blunted splenic contraction in Sherpas at high altitude, we examined changes in spleen volume during hyperoxic breathing, comparing acclimatized Sherpa with acclimatized individuals of lowland ancestry. Our study included 14 non-Sherpa (7 female) residing at altitude for a mean continuous duration of 3 months and 46 Sherpa (24 female) with an average of 4 years altitude exposure. Participants underwent a hyperoxic breathing test at altitude (4300 m; barrometric pressure = ∼430 torr;P O 2 ${P_{{{\mathrm{O}}_{\mathrm{2}}}}}$ = ∼90 torr). Throughout the test, we measured spleen volume using ultrasonography and monitored oxygen saturation (S p O 2 ${S_{{\mathrm{p}}{{\mathrm{O}}_{\mathrm{2}}}}}$ ). During rest, Sherpa exhibited larger spleens (226 ± 70 mL) compared to non-Sherpa (165 ± 34 mL; P < 0.001; effect size (ES) = 0.95, 95% CI: 0.3-1.6). In response to hyperoxia, non-Sherpa demonstrated 22 ± 12% increase in spleen size (35 ± 17 mL, 95% CI: 20.7-48.9; P < 0.001; ES = 1.8, 95% CI: 0.93-2.66), while spleen size remained unchanged in Sherpa (-2 ± 13 mL, 95% CI: -2.4 to 7.3; P = 0.640; ES = 0.18, 95% CI: -0.10 to 0.47). Our findings suggest that Sherpa and non-Sherpas of lowland ancestry exhibit distinct variations in spleen volume during hyperoxia at high altitude, potentially indicating two distinct splenic functions. In Sherpa, this phenomenon may signify a diminished splenic response to altitude-related hypoxia at rest, potentially contributing to enhanced splenic contractions during physical stress. Conversely, non-Sherpa experienced a transient increase in spleen size during hyperoxia, indicating an active tonic contraction, which may influence early altitude acclimatization in lowlanders by raising [Hb].
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Affiliation(s)
- Pontus K. Holmström
- Department of Health SciencesMid‐Sweden UniversityÖstersundSweden
- Department of Exercise ScienceSyracuse UniversitySyracuseNew YorkUSA
| | - Taylor S. Harman
- Department of AnthropologySyracuse UniversitySyracuseNew YorkUSA
| | - Anne Kalker
- Department of AnesthesiologyRadboud Medical CenterNijmegenNetherlands
| | - Bethany Steiner
- Department of Exercise ScienceSyracuse UniversitySyracuseNew YorkUSA
| | - Ella Hawkins
- Department of AnthropologySyracuse UniversitySyracuseNew YorkUSA
| | | | - Kimberly T. Zhu
- Department of AnthropologyUniversity of CaliforniaLos AngelesCaliforniaUSA
| | - Ajaya J. Kunwar
- Kathmandu Center for Genomics and Research LaboratoryGlobal Hospital, GwarkoLalitpurNepal
| | - Nilam Thakur
- Kathmandu Center for Genomics and Research LaboratoryGlobal Hospital, GwarkoLalitpurNepal
| | - Sunil Dhungel
- College of MedicineNepalese Army Institute of Health SciencesKathmanduNepal
| | - Nima Sherpa
- Local collaborator without institutional affiliation
| | - Trevor A. Day
- Department of BiologyFaculty of Science and TechnologyMount Royal UniversityCalgaryABCanada
| | | | - Abigail W. Bigham
- Department of AnthropologyUniversity of CaliforniaLos AngelesCaliforniaUSA
| | - Tom D. Brutsaert
- Department of Exercise ScienceSyracuse UniversitySyracuseNew YorkUSA
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Lindblom H, Pernett F, Schagatay E, Holmström P. Effect of exercise intensity and apnea on splenic contraction and hemoglobin increase in well-trained cross-country skiers. Eur J Appl Physiol 2024:10.1007/s00421-024-05428-z. [PMID: 38393417 DOI: 10.1007/s00421-024-05428-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 01/30/2024] [Indexed: 02/25/2024]
Abstract
The human spleen acts as a reservoir for red blood cells, which is mobilized into the systemic circulation during various conditions such as hypoxia and physical exertion. Cross-country (XC) skiers, renowned for their exceptional aerobic capacity, are regularly exposed to high-intensity exercise and local oxygen deficits. We investigated a putative dose-dependent relationship between splenic contraction and concomitant hemoglobin concentration ([Hb]) elevation across four exercise intensities in well-trained XC skiers. Fourteen male XC skiers voluntarily participated in a 2-day protocol, encompassing a serial apnea test and a [Formula: see text]O2max test (day 1), followed by three submaximal exercise intensities on a roller skiing treadmill corresponding to 55, 70, and 85% of [Formula: see text]O2max (day 2). Spleen volume was measured via ultrasonic imaging, and venous blood samples were used to determine [Hb] levels. Baseline spleen volume was similar (266(35) mL) for all conditions (NS). Notably, all conditions induced significant splenic contractions and transient [Hb] elevations. The [Formula: see text]O2max test exhibited the most pronounced splenic contraction (35.8%, p < 0.001) and a [Hb] increase of 8.1%, while the 85% exercise intensity led to 27.1% contraction and the greatest [Hb] increase (8.3%, < 0.001) compared to baseline. The apnea test induced relatively smaller responses (splenic contraction: 20.4%, [Hb] = 3.3%, p < 0.001), akin to the response observed at the 70% exercise intensity (splenic contraction = 23%, [Hb] = 6.4%, p < 0,001) and 55% (splenic contraction = 20.0%, [Hb] = 4.8%, p < 0.001). This study shows a discernible dose-dependent relationship between splenic contraction and [Hb] increase with levels of exercise, effectively distinguishing between submaximal and maximal exercise intensity.
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Affiliation(s)
- Hampus Lindblom
- Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Frank Pernett
- Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Erika Schagatay
- Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
- Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Pontus Holmström
- Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden.
- Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Östersund, Sweden.
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Joslyn LR, Huang W, Miles D, Hosseini I, Ramanujan S. "Digital twins elucidate critical role of T scm in clinical persistence of TCR-engineered cell therapy". NPJ Syst Biol Appl 2024; 10:11. [PMID: 38278838 PMCID: PMC10817974 DOI: 10.1038/s41540-024-00335-7] [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: 08/21/2023] [Accepted: 01/11/2024] [Indexed: 01/28/2024] Open
Abstract
Despite recent progress in adoptive T cell therapy for cancer, understanding and predicting the kinetics of infused T cells remains a challenge. Multiple factors can impact the distribution, expansion, and decay or persistence of infused T cells in patients. We have developed a novel quantitative systems pharmacology (QSP) model of TCR-transgenic T cell therapy in patients with solid tumors to describe the kinetics of endogenous T cells and multiple memory subsets of engineered T cells after infusion. These T cells undergo lymphodepletion, proliferation, trafficking, differentiation, and apoptosis in blood, lymph nodes, tumor site, and other peripheral tissues. Using the model, we generated patient-matched digital twins that recapitulate the circulating T cell kinetics reported from a clinical trial of TCR-engineered T cells targeting E7 in patients with metastatic HPV-associated epithelial cancers. Analyses of key parameters influencing cell kinetics and differences among digital twins identify stem cell-like memory T cells (Tscm) cells as an important determinant of both expansion and persistence and suggest that Tscm-related differences contribute significantly to the observed variability in cellular kinetics among patients. We simulated in silico clinical trials using digital twins and predict that Tscm enrichment in the infused product improves persistence of the engineered T cells and could enable administration of a lower dose. Finally, we verified the broader relevance of the QSP model, the digital twins, and findings on the importance of Tscm enrichment by predicting kinetics for two patients with pancreatic cancer treated with KRAS G12D targeting T cell therapy. This work offers insight into the key role of Tscm biology on T cell kinetics and provides a quantitative framework to evaluate cellular kinetics for future efforts in the development and clinical application of TCR-engineered T cell therapies.
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Affiliation(s)
| | - Weize Huang
- Genentech Inc., South San Francisco, CA, USA
| | - Dale Miles
- Genentech Inc., South San Francisco, CA, USA
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Mulder E, Staunton C, Sieber A, Schagatay E. Unlocking the depths: multiple factors contribute to risk for hypoxic blackout during deep freediving. Eur J Appl Physiol 2023; 123:2483-2493. [PMID: 37300699 PMCID: PMC10615935 DOI: 10.1007/s00421-023-05250-z] [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: 02/13/2023] [Accepted: 06/01/2023] [Indexed: 06/12/2023]
Abstract
PURPOSE To examine the effect of freediving depth on risk for hypoxic blackout by recording arterial oxygen saturation (SpO2) and heart rate (HR) during deep and shallow dives in the sea. METHODS Fourteen competitive freedivers conducted open-water training dives wearing a water-/pressure proof pulse oximeter continuously recording HR and SpO2. Dives were divided into deep (> 35 m) and shallow (10-25 m) post-hoc and data from one deep and one shallow dive from 10 divers were compared. RESULTS Mean ± SD depth was 53 ± 14 m for deep and 17 ± 4 m for shallow dives. Respective dive durations (120 ± 18 s and 116 ± 43 s) did not differ. Deep dives resulted in lower minimum SpO2 (58 ± 17%) compared with shallow dives (74 ± 17%; P = 0.029). Overall diving HR was 7 bpm higher in deep dives (P = 0.002) although minimum HR was similar in both types of dives (39 bpm). Three divers desaturated early at depth, of which two exhibited severe hypoxia (SpO2 ≤ 65%) upon resurfacing. Additionally, four divers developed severe hypoxia after dives. CONCLUSIONS Despite similar dive durations, oxygen desaturation was greater during deep dives, confirming increased risk of hypoxic blackout with increased depth. In addition to the rapid drop in alveolar pressure and oxygen uptake during ascent, several other risk factors associated with deep freediving were identified, including higher swimming effort and oxygen consumption, a compromised diving response, an autonomic conflict possibly causing arrhythmias, and compromised oxygen uptake at depth by lung compression possibly leading to atelectasis or pulmonary edema in some individuals. Individuals with elevated risk could likely be identified using wearable technology.
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Affiliation(s)
- Eric Mulder
- Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Kunskapens Väg 8, 831 25, Östersund, Sweden.
| | - Craig Staunton
- Swedish Winter Sports Research Centre, Mid Sweden University, Östersund, Sweden
| | - Arne Sieber
- Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Kunskapens Väg 8, 831 25, Östersund, Sweden
- Oxygen Scientific GmbH, Graz, Austria
| | - Erika Schagatay
- Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Kunskapens Väg 8, 831 25, Östersund, Sweden
- Swedish Winter Sports Research Centre, Mid Sweden University, Östersund, Sweden
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Hsia CCW. Tissue Perfusion and Diffusion and Cellular Respiration: Transport and Utilization of Oxygen. Semin Respir Crit Care Med 2023; 44:594-611. [PMID: 37541315 DOI: 10.1055/s-0043-1770061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/06/2023]
Abstract
This article provides an overview of the journey of inspired oxygen after its uptake across the alveolar-capillary interface, and the interplay among tissue perfusion, diffusion, and cellular respiration in the transport and utilization of oxygen. The critical interactions between oxygen and its facilitative carriers (hemoglobin in red blood cells and myoglobin in muscle cells), and with other respiratory and vasoactive molecules (carbon dioxide, nitric oxide, and carbon monoxide), are emphasized to illustrate how this versatile system dynamically optimizes regional convective transport and diffusive gas exchange. The rates of reciprocal gas exchange in the lung and the periphery must be well-matched and sufficient for meeting the range of energy demands from rest to maximal stress but not excessive as to become toxic. The mobile red blood cells play a vital role in matching tissue perfusion and gas exchange by dynamically regulating the controlled uptake of oxygen and communicating regional metabolic signals across different organs. Intracellular oxygen diffusion and facilitation via myoglobin into the mitochondria, and utilization via electron transport chain and oxidative phosphorylation, are summarized. Physiological and pathophysiological adaptations are briefly described. Dysfunction of any component across this integrated system affects all other components and elicits corresponding structural and functional adaptation aimed at matching the capacities across the entire system and restoring equilibrium under normal and pathological conditions.
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Affiliation(s)
- Connie C W Hsia
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
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9
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Zubac D, Obad A, Šupe-Domić D, Zec M, Bošnjak A, Ivančev V, Valić Z. Larger splenic emptying correlate with slower EPOC kinetics in healthy men and women during supine cycling. Eur J Appl Physiol 2023; 123:2271-2281. [PMID: 37270751 DOI: 10.1007/s00421-023-05244-x] [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: 12/22/2022] [Accepted: 05/25/2023] [Indexed: 06/05/2023]
Abstract
PURPOSE The present study investigated whether larger splenic emptying augments faster excess post-exercise O2 consumption (EPOC) following aerobic exercise cessation. METHODS Fifteen healthy participants (age 24 ± 4, 47% women) completed 3 laboratory visits at least 48-h apart. After obtaining medical clearance and familiarizing themselves with the test, they performed a ramp-incremental test in the supine position until task failure. At their final visit, they completed three step-transition tests from 20 W to a moderate-intensity power output (PO), equivalent to [Formula: see text]O2 at 90% gas exchange threshold, where data on metabolic, cardiovascular, and splenic responses were recorded simultaneously. After step-transition test cessation, EPOCfast was recorded, and the first 10 min of the recovery period was used for further analysis. Blood samples were collected before and immediately after the end of exercise. RESULTS In response to moderate-intensity supine cycling ([Formula: see text]O2 = ~ 2.1 L·min-1), a decrease in spleen volume of ~ 35% (p = 0.001) was observed, resulting in a transient increase in red cell count of ~ 3-4% (p = 0.001) in mixed venous blood. In parallel, mean blood pressure, heart rate, and stroke volume increased by 30-100%, respectively. During recovery, mean τ[Formula: see text]O2 was 45 ± 18 s, the amplitude was 2.4 ± 0.5 L·min-1, and EPOCfast was 1.69 L·O2. Significant correlations were observed between the percent change in spleen volume and (i) EPOCfast (r = - 0.657, p = 0.008) and (ii) τ[Formula: see text]O2 (r = - 0.619, p = 0.008), but not between the change in spleen volume and (iii) [Formula: see text]O2 peak (r = 0.435, p = 0.105). CONCLUSION Apparently, during supine cycling, individuals with larger spleen emptying tend to have slower [Formula: see text] O2 recovery kinetics and a greater EPOCfast.
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Affiliation(s)
- Damir Zubac
- Department 1 of Internal Medicine, Center for Integrated Oncology Aachen, Bonn, Cologne, Düsseldorf, University Hospital of Cologne, Cologne, Germany.
- Science and Research Center Koper, Institute for Kinesiology Research, Koper, Slovenia.
- Faculty of Kinesiology, University of Split, Split, Croatia.
| | - Ante Obad
- University Department for Health Studies, University of Split, Split, Croatia
| | - Daniela Šupe-Domić
- University Department for Health Studies, University of Split, Split, Croatia
- Department of Medical Laboratory Diagnostics, University Hospital Center Split, Split, Croatia
| | - Mirela Zec
- Department of Medical Laboratory Diagnostics, University Hospital Center Split, Split, Croatia
| | | | | | - Zoran Valić
- School of Medicine, Department of Integrative Physiology, University of Split, Split, Croatia
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10
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Pernett F, Bergenhed P, Holmström P, Mulder E, Schagatay E. Effects of hyperventilation on oxygenation, apnea breaking points, diving response, and spleen contraction during serial static apneas. Eur J Appl Physiol 2023; 123:1809-1824. [PMID: 37060440 PMCID: PMC10363065 DOI: 10.1007/s00421-023-05202-7] [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: 11/22/2022] [Accepted: 04/07/2023] [Indexed: 04/16/2023]
Abstract
PURPOSE Hyperventilation is considered a major risk factor for hypoxic blackout during breath-hold diving, as it delays the apnea breaking point. However, little is known about how it affects oxygenation, the diving response, and spleen contraction during serial breath-holding. METHODS 18 volunteers with little or no experience in freediving performed two series of 5 apneas with cold facial immersion to maximal duration at 2-min intervals. In one series, apnea was preceded by normal breathing and in the other by 15 s of hyperventilation. End-tidal oxygen and end-tidal carbon dioxide were measured before and after every apnea, and peripheral oxygen saturation, heart rate, breathing movements, and skin blood flow were measured continuously. Spleen dimensions were measured every 15 s. RESULTS Apnea duration was longer after hyperventilation (133 vs 111 s). Hyperventilation reduced pre-apnea end-tidal CO2 (17.4 vs 29.0 mmHg) and post-apnea end-tidal CO2 (38.5 vs 40.3 mmHg), and delayed onset of involuntary breathing movements (112 vs 89 s). End-tidal O2 after apnea was lower in the hyperventilation trial (83.4 vs 89.4 mmHg) and so was the peripheral oxygen saturation nadir after apnea (90.6 vs 93.6%). During hyperventilation, the nadir peripheral oxygen saturation was lower in the last apnea than in the first (94.0% vs 86.7%). There were no differences in diving response or spleen volume reduction between conditions or across series. CONCLUSIONS Serial apneas revealed a previously undescribed aspect of hyperventilation; a progressively increased desaturation across the series, not observed after normal breathing and could heighten the risk of a blackout.
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Affiliation(s)
- Frank Pernett
- Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Östersund, Sweden.
| | - Pontus Bergenhed
- Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Pontus Holmström
- Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Eric Mulder
- Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Erika Schagatay
- Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
- Swedish Winter Sports Research Centre, Östersund, Sweden
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11
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Massini DA, Scaggion D, DE Oliveira TP, Macedo AG, Almeida TF, Pessôa Filho DM. Training methods for maximal static apnea performance: a systematic review and meta-analysis. J Sports Med Phys Fitness 2023; 63:77-85. [PMID: 35437303 DOI: 10.23736/s0022-4707.22.13621-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Currently, there is an increase in people practicing freediving (FD) both in competition and leisure. As a sports practice, its modalities are grouped into static, dynamic, and constant weight apnea. The aim of this systematic review and meta-analysis (PROSPERO-CRD42021230322) was to identify the training methods used to improve the static apnea time (AT) performance. EVIDENCE ACQUISITION Ten training protocols were analyzed from eight studies published until March 09, 2022. The effect size (Hedge's g) and its confidence interval (CI<inf>95%</inf>) were calculated from the AT measured pre- and post-training. EVIDENCE SYNTHESIS Three different apnea training methods were verified, the breath-hold (BH) that uses BH exercises, physical training with strength and cardiorespiratory exercises, and cross training that combines BH exercises with physical training. These training methods were applied to 138 participants of both sexes with or without experience in apnea episode or diving practice. In general, the AT improvement showed a large effect after the interventions (g=1.30, CI<inf>95%</inf>=0.85-1.76, P<0.01). CONCLUSIONS All three methods were effective in improving static AT, however from the existing protocols is not possible to recommend an ideal to improve AT and therefore FD performance.
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Affiliation(s)
- Danilo A Massini
- Post-Graduate Program in Human Development and Technology from São Paulo State University (UNESP), Rio Claro, Brazil.,University Center of São Paulo State (UNICEP), Rio Claro, Brazil.,São Paulo State University (UNESP), Bauru, Brazil
| | - Danilo Scaggion
- University Center of São Paulo State (UNICEP), Rio Claro, Brazil
| | - Thiago P DE Oliveira
- Post-Graduate Program in Human Development and Technology from São Paulo State University (UNESP), Rio Claro, Brazil
| | - Anderson G Macedo
- Post-Graduate Program in Human Development and Technology from São Paulo State University (UNESP), Rio Claro, Brazil.,São Paulo State University (UNESP), Bauru, Brazil
| | - Tiago F Almeida
- São Paulo State University (UNESP), Bauru, Brazil - .,CIPER, Faculty of Human Kinetics, University of Lisbon, Lisbon, Portugal
| | - Dalton M Pessôa Filho
- Post-Graduate Program in Human Development and Technology from São Paulo State University (UNESP), Rio Claro, Brazil.,São Paulo State University (UNESP), Bauru, Brazil
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12
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Persson G, Lodin-Sundström A, Linér MH, Andersson SHA, Sjögreen B, Andersson JPA. Splenic contraction and cardiovascular responses are augmented during apnea compared to rebreathing in humans. Front Physiol 2023; 14:1109958. [PMID: 36960158 PMCID: PMC10028099 DOI: 10.3389/fphys.2023.1109958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 02/22/2023] [Indexed: 03/09/2023] Open
Abstract
The spleen contracts during apnea, releasing stored erythrocytes, thereby increasing systemic hemoglobin concentration (Hb). We compared apnea and rebreathing periods, of equal sub-maximal duration (mean 137 s; SD 30), in eighteen subjects to evaluate whether respiratory arrest or hypoxic and hypercapnic chemoreceptor stimulation is the primary elicitor of splenic contraction and cardiovascular responses during apnea. Spleen volume, Hb, cardiovascular variables, arterial (SaO2), cerebral (ScO2), and deltoid muscle oxygen saturations (SmO2) were recorded during the trials and end-tidal partial pressure of oxygen (PETO2) and carbon dioxide (PETCO2) were measured before and after maneuvers. The spleen volume was smaller after apnea, 213 (89) mL, than after rebreathing, 239 (95) mL, corresponding to relative reductions from control by 20.8 (17.8) % and 11.6 (8.0) %, respectively. The Hb increased 2.4 (2.0) % during apnea, while there was no significant change with rebreathing. The cardiovascular responses, including bradycardia, decrease in cardiac output, and increase in total peripheral resistance, were augmented during apnea compared to during rebreathing. The PETO2 was higher, and the PETCO2 was lower, after apnea compared to after rebreathing. The ScO2 was maintained during maneuvers. The SaO2 decreased 3.8 (3.1) % during apnea, and even more, 5.4 (4.4) %, during rebreathing, while the SmO2 decreased less during rebreathing, 2.2 (2.8) %, than during apnea, 8.3 (6.2) %. We conclude that respiratory arrest per se is an important stimulus for splenic contraction and Hb increase during apnea, as well as an important initiating factor for the apnea-associated cardiovascular responses and their oxygen-conserving effects.
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Affiliation(s)
- Gustav Persson
- Department of Experimental Medical Science, Lund University, Lund, Sweden
- *Correspondence: Gustav Persson, ; Johan P. A. Andersson,
| | - Angelica Lodin-Sundström
- Department of Health Sciences, Mid Sweden University, Sundsvall, Sweden
- Department of Biology, Lund University, Lund, Sweden
| | - Mats H. Linér
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Samuel H. A. Andersson
- Department of Biology, Lund University, Lund, Sweden
- Department of Clinical Sciences, Malmö, Lund University, Lund, Sweden
| | | | - Johan P. A. Andersson
- Department of Experimental Medical Science, Lund University, Lund, Sweden
- *Correspondence: Gustav Persson, ; Johan P. A. Andersson,
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13
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Muacevic A, Adler JR, Zidan M, Elgyoum A, Hassan H, Abdelrahman O. Estimation of Spleen Volume Using MRI Segmentation: Would One Slice Be Enough? Cureus 2022; 14:e32165. [PMID: 36601193 PMCID: PMC9806286 DOI: 10.7759/cureus.32165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/03/2022] [Indexed: 12/07/2022] Open
Abstract
This study aimed to establish spleen volume in adult Sudanese using manual segmentation and the Cavalieri method with magnetic resonance images (MRI). A total of 345 abdominal MRI scans for adults were retrospectively studied for patients who underwent abdomen MRI between September to October 2016. The data were collected from two scanning centers in Khartoum, Sudan. For each series of sectional images, the spleen was manually segmented, and the volume was calculated using matrix laboratory (MATLAB) code. Furthermore, abdominal circumferences and diameters, in addition to L1 body dimension and spinal canal, were measured. The mean splenic volume in our study was 187.2 cm3, without a significant change with age (P = 0.269). The average volume in males was 223.5 cm3 while in females it was 170.27 cm3. The average coefficient error (CE) was 0.029. A positive significant correlation was found between the volume and spleen length (beta standardized coefficient = 0.781, P < 0.05). The mean length was 9.18 cm. Additionally, our data showed an insignificant correlation between the volume and the other measurements, except for the abdomen transverse diameter (beta standardized coefficient = 0.267, P < 0.05). The results of our study coincided with previous studies in the normal range of spleen volume and the strong correlation with length, regardless of the irregular shape of the spleen. In addition, manual segmentation was a reliable method to measure spleen volume objectively. However, our single-slice measurements were insufficient.
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14
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Holmström P, Pernett F, Schagatay E. Test-retest reliability of splenic volume assessment by ultrasonography. Sci Rep 2022; 12:18976. [PMID: 36347952 PMCID: PMC9643442 DOI: 10.1038/s41598-022-23384-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 10/31/2022] [Indexed: 11/09/2022] Open
Abstract
While MRI and CT are the gold standards for assessments of splenic size in clinical settings, ultrasonography is particularly suited due to its portability, cost efficiency and easy utilization. However, ultrasonography is associated with subjective assessment, potentially resulting in increased variation. We used a test-retest design aiming to determine the reliability of splenic measurements assessed by ultrasonography during apnea. In addition, we compared reliability between different equations for volume calculations: Koga, Prolate ellipsoid and Pilström. Twelve healthy participants (6 women) performed two tests separated by 15 min, comprising a maximal voluntary apnea in a seated position. Splenic dimensions were measured via ultrasonography for 5 min before and immediately following apnea. Resting splenic volume displayed high test-retest reliability between tests (Pilström: 157 ± 39 mL vs 156 ± 34 mL, p = .651, ICC = .970, p < .001, CV = 2.98 ± 0.1%; Prolate ellipsoid: 154 ± 37 mL vs 144 ± 43 mL, p = .122, ICC = .942, p < .001, CV = 5.47 ± 0.3%; Koga: 142 ± 37 mL vs 140 ± 59 mL, p = .845, ICC = .859, p < .001, CV = 9.72 ± 1.4%). Apnea-induced volumes displayed similar reliability (127 ± 29 mL vs 129 ± 28 mL, p = .359, ICC = .967, p < .001, CV = 3.14 ± 3.1%). Reliability was also high between equations (Pilström vs Prolate ellipsoid: ICC = .818, p < .001, CV = 7.33 ± 0.3%, bias = - 3.1 mL, LoA = - 46.9 to 40.7 mL; Pilström vs Koga: ICC = .618, p < .01, CV = 11.83 ± 1.1%, bias = - 14.8 mL, LoA = - 76.9 to 47.3 mL). We conclude that splenic ultrasonographic measurements have practical applications during laboratory and field-based research as a reliable method detecting splenic volume change consistently between repeated tests. The Pilström equation displayed similar reliability compared to the prolate ellipsoid formula and slightly higher compared to the Koga formula and may be particularly useful to account for individual differences in splenic dimensions.
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Affiliation(s)
- Pontus Holmström
- grid.29050.3e0000 0001 1530 0805Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Kunskapsgatan 4, 83140 Östersund, Sweden
| | - Frank Pernett
- grid.29050.3e0000 0001 1530 0805Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Kunskapsgatan 4, 83140 Östersund, Sweden
| | - Erika Schagatay
- grid.29050.3e0000 0001 1530 0805Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Kunskapsgatan 4, 83140 Östersund, Sweden ,grid.29050.3e0000 0001 1530 0805Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
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15
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Keeler JM, Hess HW, Tourula E, Baker TB, Kerr PM, Greenshields JT, Chapman RF, Johnson BD, Schlader ZJ. Increased spleen volume provoked by temperate head-out-of-water immersion. Am J Physiol Regul Integr Comp Physiol 2022; 323:R776-R786. [PMID: 36121146 PMCID: PMC9639762 DOI: 10.1152/ajpregu.00111.2022] [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: 05/20/2022] [Revised: 09/14/2022] [Accepted: 09/14/2022] [Indexed: 11/22/2022]
Abstract
This study tested the hypotheses that 1) spleen volume increases during head-out-of-water immersion (HOWI) and returns to pre-HOWI values postdiuresis, and 2) the magnitude of apnea-induced spleen contraction increases when preapnea spleen volume is elevated. Spleen volume was measured before and after a set of five apneas in 12 healthy adults (28 ± 5 yr, 3 females) before, during (at 30 and 150 min), and 20 min after temperate temperature (36 ± 1°C) HOWI. At each time point, spleen length, width, and thickness were measured via ultrasound, and spleen volume was calculated using the Pilström equation. Compared with pre-HOWI (276 ± 88 mL), spleen volume was elevated at 30 (353 ± 94 mL, P < 0.01) and 150 (322 ± 87 mL, P < 0.01) min of HOWI but returned to pre-HOWI volume at post-HOWI (281 ± 90 mL, P = 0.58). Spleen volume decreased from pre- to postapnea bouts at each time point (P < 0.01). The magnitude of reduction in spleen volume from pre- to postapneas was elevated at 30 min of HOWI (-69 ± 24 mL) compared with pre-HOWI (-52 ± 20 mL, P = 0.04) but did not differ from pre-HOWI at 150 min of HOWI (-54 ± 16 mL, P = 0.99) and post-HOWI (-50 ± 18 mL, P = 0.87). Thus, spleen volume is increased throughout 180 min of HOWI, and whereas apnea-induced spleen contraction is augmented after 30 min of HOWI, the magnitude of spleen contraction is unaffected by HOWI thereafter.
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Affiliation(s)
- Jason M Keeler
- H. H. Morris Human Performance Laboratories, Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | - Hayden W Hess
- H. H. Morris Human Performance Laboratories, Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | - Erica Tourula
- H. H. Morris Human Performance Laboratories, Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | - Tyler B Baker
- H. H. Morris Human Performance Laboratories, Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | - Payton M Kerr
- H. H. Morris Human Performance Laboratories, Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | - Joel T Greenshields
- H. H. Morris Human Performance Laboratories, Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | - Robert F Chapman
- H. H. Morris Human Performance Laboratories, Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | - Blair D Johnson
- H. H. Morris Human Performance Laboratories, Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | - Zachary J Schlader
- H. H. Morris Human Performance Laboratories, Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
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16
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Yang K, Wang WB, Yu ZH, Cui XL, Yu ZB, Jiang Y, Gou JF, Du MM. Eight weeks of dry dynamic breath-hold training results in larger spleen volume but does not increase haemoglobin concentration. Front Physiol 2022; 13:925539. [PMID: 36277212 PMCID: PMC9585269 DOI: 10.3389/fphys.2022.925539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Purpose: It has previously been reported that repeated exposure to hypoxia increases spleen size and haemoglobin (HGB) level and recent reports on the effect apnoea has on spleen size and haematological parameters are contradictory. Therefore, this study aims to evaluate the effect apnoea training has on spleen size and haematological parameters. Methods: The breath-holding (BH) group was comprised of 12 local student-athletes with no BH exercise experience who performed BH jogging and BH jumping rope dynamic apnoea protocols, five times weekly for 8 weeks. The BH event duration was progressively increased as the apnoea tolerance of the athletes improved (20 to 35 s). The same training task was performed by the control group (n = 10) without BH. Spleen sizes were measured with an ultrasound system and a complete blood cell analysis was performed on the median cubital venous blood. Results: Spleen volume in the BH group increased from 109 ± 13 ml to 136 ± 13 ml (p < 0.001), and bulky platelets decreased from 70.50 ± 5.83 to 65.17 ± 5.87 (p = 0.034), but no changes were recorded for erythrocytes (p = 0.914), HGB (p = 0.637), PLTs (p = 0.346) and WBC (p = 0.532). No changes were recorded for the control group regarding spleen size or haematological parameters. Conclusion: Eight weeks of dry dynamic apnoea training increased spleen size and decreased the number of circulating bulky platelets in the athletes who were assessed in this study. However, the baseline RBC counts and HGB levels of the athletes were not altered by the training programme.
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Affiliation(s)
- Kun Yang
- School of Physical Education, Guizhou University, Guiyang, Guizhou, China
| | - Wen-Bin Wang
- School of Physical Education, Guizhou University, Guiyang, Guizhou, China
| | - Ze-Hua Yu
- Graduate School, Guangzhou Sport University, Guangzhou, Guangdong, China
| | - Xiao-Lan Cui
- School of Physical Education, Guizhou University, Guiyang, Guizhou, China
| | - Zhang-Biao Yu
- School of Physical Education, Guizhou University, Guiyang, Guizhou, China
- *Correspondence: Zhang-Biao Yu,
| | - Yi Jiang
- School of Physical Education, Guizhou University, Guiyang, Guizhou, China
| | - Jin-Fei Gou
- School of Physical Education, Guizhou University, Guiyang, Guizhou, China
| | - Meng-Meng Du
- School of Physical Education, Guizhou University, Guiyang, Guizhou, China
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17
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de Asís-Fernández F, Sereno D, Turner AP, González-Mohíno F, González-Ravé JM. Effects of apnoea training on aerobic and anaerobic performance: A systematic review and meta-analysis. Front Physiol 2022; 13:964144. [PMID: 36237527 PMCID: PMC9551563 DOI: 10.3389/fphys.2022.964144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 08/15/2022] [Indexed: 11/13/2022] Open
Abstract
Background Trained breath-hold divers have shown physiological adaptations that might improve athletes’ aerobic and anaerobic performance.Objective This study aimed to systematically review the scientific literature and perform a meta-analysis to assess the effects of voluntary apnoea training on markers of anaerobic and aerobic performance, such as blood lactate and VO2max.Methods A literature search on three databases (Web of Science, PubMed and SCOPUS) was conducted in March 2022. The inclusion criteria were 1) peer-reviewed journal publication; 2) clinical trials; 3) healthy humans; 4) effects of apnoea training; 5) variables included markers of aerobic or anaerobic performance, such as lactate and VO2max.Results 545 manuscripts were identified following database examination. Only seven studies met the inclusion criteria and were, therefore, included in the meta-analysis. 126 participants were allocated to either voluntary apnoea training (ApT; n = 64) or normal breathing (NB; n = 63). Meta-analysis on the included studies demonstrated that ApT increased the peak blood lactate concentration more than NB (MD = 1.89 mmol*L−1 [95% CI 1.05, 2.73], z = 4.40, p < 0.0001). In contrast, there were no statistically significant effects of ApT on VO2max (MD = 0.89 ml*kg−1*min−1 [95% CI −1.23, 3.01], z = 0.82, p = 0.41).Conclusion ApT might be an alternative strategy to enhace anaerobic performance associated with increased maximum blood lactate; however, we did not find evidence of ApT effects on physiological aerobic markers, such as VO2max.Systematic Review Registration: [PRISMA], identifier [registration number].
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Affiliation(s)
- Francisco de Asís-Fernández
- Departamento de Fisioterapia, Facultad de Ciencias de la Salud, Centro Superior de Estudios Universitarios La Salle, Universidad Autónoma de Madrid, Madrid, Spain
- Breatherapy Research Group, Instituto de Neurociencias y Ciencias del Movimiento (INCIMOV), Centro Superior de Estudios Universitarios La Salle, Universidad Autónoma de Madrid, Madrid, Spain
| | - Daniel Sereno
- Breatherapy Research Group, Instituto de Neurociencias y Ciencias del Movimiento (INCIMOV), Centro Superior de Estudios Universitarios La Salle, Universidad Autónoma de Madrid, Madrid, Spain
- Sports Training Laboratory, Faculty of Sports Sciences, Universidad de Castilla-La Mancha, Toledo, Spain
| | - Anthony P. Turner
- Sport, Physical Education and Health Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Fernando González-Mohíno
- Sports Training Laboratory, Faculty of Sports Sciences, Universidad de Castilla-La Mancha, Toledo, Spain
- Facultad de Ciencias de la Vida y de la Naturaleza, Universidad Nebrija, Madrid, Spain
- *Correspondence: Fernando González-Mohíno,
| | - José María González-Ravé
- Sports Training Laboratory, Faculty of Sports Sciences, Universidad de Castilla-La Mancha, Toledo, Spain
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18
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McKenzie MR, McKean MR, Doyle DP, Hogarth LW, Burkett BJ. Swimming performance, physiology, and post-activation performance enhancement following dryland transition phase warmup: A systematic review. PLoS One 2022; 17:e0273248. [PMID: 35980952 PMCID: PMC9387820 DOI: 10.1371/journal.pone.0273248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 08/03/2022] [Indexed: 11/18/2022] Open
Abstract
Background In swimming, the period between the end of the swimming warmup and the beginning of competition is critical to performance, here termed the transition phase. Several options are available during this phase, necessitating a systematic review to understand if optimal strategies exist. Objectives To synthesise and critically evaluate the current literature investigating land-based warmup interventions on subsequent performance in competitive swimmers. Methods A search of three electronic databases (PubMed, EBSCO SPORTDiscus and Web of Science) was conducted to identify original studies until February 2022. Selection criteria dictated that (i) a control condition was used, (ii) participants were ≥ 15 years of age, (iii) a pool-based warmup was done prior to the land-based warmup. A total of 25 articles met the selection criteria. Results Reducing the transition phase duration by at least half led to consistently faster time-trial times of between 1.1–1.5% for all included studies. Passive warmups using clothing interventions resulted in mostly faster time-trial’s of 0.4–0.8% with increases in skin temperature frequent, though little change occurred in core temperature. The methodology of passive respiratory warmups were vastly different with positive time-trial’s effects ranging between 0.9–1.1% for two studies, though one reported no meaningful difference. Active warmups led to consistently faster time-trial’s between 0.7–0.9%, though the unpinning factors are not clear. Warmups which combined passive and active options frequently led to faster time-trial’s between 0.8–3%. Upper and combined limb post-activation performance enhancement led to mostly unfavourable time-trial changes. Lower limb exclusive protocols results were inconsistent, with limited beneficial effects on time-trial or start performance reported following plyometric protocols. However, there does appear merit in heavier loaded lower limb protocols. Conclusion Each of a reduced transition phase length, and passive, active or combination warmup have demonstrated improvements in swimming performance. Conversely, PAPE protocols should be used with caution, especially when including the upper limbs.
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Affiliation(s)
- Max R. McKenzie
- Queensland Academy of Sport, Brisbane, Queensland, Australia
- School of Health and Behavioural Sciences, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
- * E-mail:
| | - Mark R. McKean
- Queensland Academy of Sport, Brisbane, Queensland, Australia
- School of Health and Behavioural Sciences, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Danielle P. Doyle
- Queensland Academy of Sport, Brisbane, Queensland, Australia
- School of Health and Behavioural Sciences, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Luke W. Hogarth
- School of Health and Behavioural Sciences, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Brendan J. Burkett
- School of Health and Behavioural Sciences, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
- Swimming Australia, Brisbane, Queensland, Australia
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19
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Arce-Álvarez A, Salazar-Ardiles C, Cornejo C, Paez V, Vásquez-Muñoz M, Stillner-Vilches K, Jara CR, Ramirez-Campillo R, Izquierdo M, Andrade DC. Chemoreflex Control as the Cornerstone in Immersion Water Sports: Possible Role on Breath-Hold. Front Physiol 2022; 13:894921. [PMID: 35733994 PMCID: PMC9207453 DOI: 10.3389/fphys.2022.894921] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 05/10/2022] [Indexed: 11/30/2022] Open
Abstract
Immersion water sports involve long-term apneas; therefore, athletes must physiologically adapt to maintain muscle oxygenation, despite not performing pulmonary ventilation. Breath-holding (i.e., apnea) is common in water sports, and it involves a decrease and increases PaO2 and PaCO2, respectively, as the primary signals that trigger the end of apnea. The principal physiological O2 sensors are the carotid bodies, which are able to detect arterial gases and metabolic alterations before reaching the brain, which aids in adjusting the cardiorespiratory system. Moreover, the principal H+/CO2 sensor is the retrotrapezoid nucleus, which is located at the brainstem level; this mechanism contributes to detecting respiratory and metabolic acidosis. Although these sensors have been characterized in pathophysiological states, current evidence shows a possible role for these mechanisms as physiological sensors during voluntary apnea. Divers and swimmer athletes have been found to displayed longer apnea times than land sports athletes, as well as decreased peripheral O2 and central CO2 chemoreflex control. However, although chemosensitivity at rest could be decreased, we recently found marked sympathoexcitation during maximum voluntary apnea in young swimmers, which could activate the spleen (which is a reservoir organ for oxygenated blood). Therefore, it is possible that the chemoreflex, autonomic function, and storage/delivery oxygen organ(s) are linked to apnea in immersion water sports. In this review, we summarized the available evidence related to chemoreflex control in immersion water sports. Subsequently, we propose a possible physiological mechanistic model that could contribute to providing new avenues for understanding the respiratory physiology of water sports.
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Affiliation(s)
- Alexis Arce-Álvarez
- Exercise Applied Physiology Laboratory, Centro de Investigación en Fisiología y Medicina de Altura, Departamento Biomedico, Facultad de Ciencias de La Salud, Universidad de Antofagasta, Antofagasta, Chile
- Escuela de Kinesiología, Facultad de Salud, Universidad Católica Silva Henríquez, Santiago, Chile
- Navarrabiomed, Hospital Universitario de Navarra (CHN), Universidad Pública de Navarra (UPNA), IdiSNA, Pamplona, Spain
| | - Camila Salazar-Ardiles
- Exercise Applied Physiology Laboratory, Centro de Investigación en Fisiología y Medicina de Altura, Departamento Biomedico, Facultad de Ciencias de La Salud, Universidad de Antofagasta, Antofagasta, Chile
| | - Carlos Cornejo
- Exercise Applied Physiology Laboratory, Centro de Investigación en Fisiología y Medicina de Altura, Departamento Biomedico, Facultad de Ciencias de La Salud, Universidad de Antofagasta, Antofagasta, Chile
| | - Valeria Paez
- Exercise Applied Physiology Laboratory, Centro de Investigación en Fisiología y Medicina de Altura, Departamento Biomedico, Facultad de Ciencias de La Salud, Universidad de Antofagasta, Antofagasta, Chile
| | - Manuel Vásquez-Muñoz
- Navarrabiomed, Hospital Universitario de Navarra (CHN), Universidad Pública de Navarra (UPNA), IdiSNA, Pamplona, Spain
- Clínica Santa María, Santiago, Chile
| | | | - Catherine R. Jara
- Exercise Applied Physiology Laboratory, Centro de Investigación en Fisiología y Medicina de Altura, Departamento Biomedico, Facultad de Ciencias de La Salud, Universidad de Antofagasta, Antofagasta, Chile
| | - Rodrigo Ramirez-Campillo
- Exercise and Rehabilitation Sciences Laboratory, School of Physical Therapy, Faculty of Rehabilitation Sciences, Universidad Andres Bello, Santiago, Chile
| | - Mikel Izquierdo
- Navarrabiomed, Hospital Universitario de Navarra (CHN), Universidad Pública de Navarra (UPNA), IdiSNA, Pamplona, Spain
| | - David C. Andrade
- Exercise Applied Physiology Laboratory, Centro de Investigación en Fisiología y Medicina de Altura, Departamento Biomedico, Facultad de Ciencias de La Salud, Universidad de Antofagasta, Antofagasta, Chile
- *Correspondence: David C. Andrade, ,
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No differences in splenic emptying during on-transient supine cycling between aerobically trained and untrained participants. Eur J Appl Physiol 2022; 122:903-917. [PMID: 35013810 PMCID: PMC8747858 DOI: 10.1007/s00421-021-04843-w] [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: 07/09/2021] [Accepted: 11/09/2021] [Indexed: 11/17/2022]
Abstract
Purpose The role of splenic emptying in O2 transport during aerobic exercise still remains a matter of debate. Our study compared the differences in spleen volume changes between aerobically trained and untrained individuals during step-transition supine cycling exercise at moderate-intensity. We also examined the relationship between spleen volume changes, erythrocyte release, and O2 uptake parameters. Methods Fourteen healthy men completed all study procedures, including a detailed medical examination, supine maximal O2 uptake (\documentclass[12pt]{minimal}
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\begin{document}$${\dot{\text{V}}\text{O}}_{2}$$\end{document}V˙O2 max.) test, and three step-transitions from 20 W to a moderate-intensity power output, equivalent to \documentclass[12pt]{minimal}
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\begin{document}$${\dot{\text{V}}\text{O}}_{2}$$\end{document}V˙O2 uptake at 90% gas exchange threshold. During these step-transitions pulmonary \documentclass[12pt]{minimal}
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\begin{document}$${\dot{\text{V}}\text{O}}_{{2{\text{p}}}}$$\end{document}V˙O2p, near-infrared spectroscopy of the vastus lateralis, and cardiovascular responses were continuously measured. In parallel, minute-by-minute ultrasonic measurements of the spleen were performed. Blood samples were taken before and immediately after step-transition cycling. Results On average, \documentclass[12pt]{minimal}
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\begin{document}$${\dot{\text{V}}\text{O}}_{2}$$\end{document}V˙O2 max. was 10 mL kg min−1 (p = 0.001) higher in trained compared to their aerobically untrained peers. In response to supine step-transition cycling, the splenic volume was significantly reduced, and the largest reduction (~ 106 to 115 mL, ~ 38%, p = 0.001) was similar in both aerobically trained and untrained individuals. Erythrocyte concentration and platelet count transiently increased after exercise cessation, with no differences observed between groups. However, the vastus lateralis deoxygenation amplitude was 30% (p = 0.001) greater in trained compared to untrained individuals. No associations existed between: (i) spleen volumes at rest (ii) spleen volume changes (%), (iii) resting hematocrit and oxygen uptake parameters. Conclusion Greater splenic emptying and subsequent erythrocyte release do not lead to a slower \documentclass[12pt]{minimal}
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\begin{document}$$\tau {\dot{\text{V}}\text{O}}_{{2{\text{p}}}}$$\end{document}τV˙O2p, regardless of individual \documentclass[12pt]{minimal}
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Citherlet T, Crettaz von Roten F, Kayser B, Guex K. Acute Effects of the Wim Hof Breathing Method on Repeated Sprint Ability: A Pilot Study. Front Sports Act Living 2021; 3:700757. [PMID: 34514386 PMCID: PMC8424088 DOI: 10.3389/fspor.2021.700757] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 07/02/2021] [Indexed: 11/23/2022] Open
Abstract
The Wim Hof breathing method (WHBM) combines periods of hyperventilation (HV) followed by voluntary breath-holds (BH) at low lung volume. It has been increasingly adopted by coaches and their athletes to improve performance, but there was no published research on its effects. We determined the feasibility of implementing a single WHBM session before repeated sprinting performance and evaluated any acute ergogenic effects. Fifteen amateur runners performed a single WHBM session prior to a Repeated Ability Sprint Test (RAST) in comparison to voluntary HV or spontaneous breathing (SB) (control) in a randomized cross-over design. Gas exchange, heart rate, and finger pulse oxygen saturation (SpO2) were monitored. Despite large physiological effects in the SpO2 and expired carbon dioxide (VCO2) levels of both HV and WHBM, no significant positive or negative condition effects were found on RAST peak power, average power, or fatigue index. Finger SpO2 dropped to 60 ± 12% at the end of the BHs. Upon the last HV in the WHBM and HV conditions, end-tidal CO2 partial pressure (PETCO2) values were 19 ± 3 and 17 ± 3 mmHg, indicative of respiratory alkalosis with estimated arterial pH increases of +0.171 and of +0.181, respectively. Upon completion of RAST, 8 min cumulated expired carbon dioxide volumes in the WHBM and HV were greater than in SB, suggesting lingering carbon dioxide stores depletion. These findings indicate that despite large physiological effects, a single WHBM session does not improve anaerobic performance in repeated sprinting exercise.
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Affiliation(s)
- Tom Citherlet
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | | | - Bengt Kayser
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Kenny Guex
- School of Health Sciences, University of Applied Sciences and Arts Western Switzerland, Lausanne, Switzerland
- Swiss Athletics, Haus des Sports, Ittigen, Switzerland
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22
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Zubac D, Obad A, Bosnjak A, Zec M, Ivancev V, Valic Z. Spleen Emptying Does Not Correlate With Faster Oxygen Kinetics During a Step-Transition Supine Cycling. Appl Physiol Nutr Metab 2021; 46:1425-1429. [PMID: 34166599 DOI: 10.1139/apnm-2021-0294] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This manuscript quantified spleen volume changes and examined the relationship between those changes and V̇O2 kinetics during supine cycling. Ten volunteers (age=22±3), completed three step-transitions from 20 W to their power output at 90% gas exchange threshold. Ultrasonic measurements of the spleen were performed each minute. The largest spleen volume reduction was 105 mL (p=.001). No associations existed between: i) spleen volumes at rest ii) spleen volume changes (%) and τV̇O2p. Larger resting spleen volume and greater emptying do not correlate with a faster τV̇O2p. Novelty: • Greater splenic contractions do not augment τV̇O2p, irrespective of spleen emptying and subsequent erythrocyte release.
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Affiliation(s)
- Damir Zubac
- Science and Research Center Koper, Institute for Kinesiology Research, Koper, Slovenia.,University of Split, Faculty of Kinesiology, Split, Croatia;
| | - Ante Obad
- University of Split, 74422, Split, Splitsko-dalmatinska, Croatia;
| | - Ana Bosnjak
- University of Split, 74422, Split, Splitsko-dalmatinska, Croatia;
| | - Mirela Zec
- University of Split, 74422, Split, Splitsko-dalmatinska, Croatia;
| | | | - Zoran Valic
- University of Split Faculty of Medicine, 89252, Physiology, Soltanska 2, Split, Croatia, 21000;
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23
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Holmström PK, Karlsson Ö, Lindblom H, McGawley K, Schagatay EK. Enhanced splenic volume and contraction in elite endurance athletes. J Appl Physiol (1985) 2021; 131:474-486. [PMID: 34166106 DOI: 10.1152/japplphysiol.01066.2020] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Splenic contraction, which leads to ejection of stored erythrocytes, is greater in athletes involved in regular freediving or high-altitude activities. As this response facilitates oxygen-carrying capacity, similar characteristics may be expected of elite endurance athletes. Therefore, our aims were to compare resting and apnea-induced splenic volume in endurance athletes and untrained individuals, and to assess the athletes' exercise-induced splenic volume. Twelve elite biathletes (7 women) and 12 controls (6 women) performed a maximal effort apnea in a seated position. In addition, the biathletes completed a maximal roller-skiing time trial. Splenic dimensions were measured by ultrasonic imaging for subsequent volume calculations, whereas Hb was analyzed from capillary blood samples and cardiorespiratory variables were monitored continuously. Baseline splenic volume was larger in the biathletes (214 ± 56 mL) compared with controls (157 ± 39 mL, P = 0.008) and apnea-induced splenic contraction was also greater in the biathletes (46 ± 20 mL vs. 30 ± 16 mL, P = 0.035). Hb increased immediately after apnea in the biathletes (4.5 ± 4.8%, P = 0.029) but not in the controls (-0.7 ± 3.1%, P = 0.999). Increases in exercise-induced splenic contraction (P = 0.008) and Hb (P = 0.001) were greater compared with the apnea-induced responses among the athletes. Baseline splenic volume tended to be correlated with V̇o2max (r = 0.584, P = 0.059). We conclude that elite biathletes have greater splenic volume with a greater ability to contract and elevate Hb compared with untrained individuals. These characteristics may transiently enhance O2-carrying capacity and possibly increase O2 uptake, thereby helping biathletes to cope with high intermittent O2 demands and severe O2 deficits that occur during biathlon training and competition.NEW & NOTEWORTHY This study demonstrates that elite biathletes have larger splenic volume, apnea-induced splenic contraction, and Hb elevation compared with untrained individuals, which is likely functional to cope with high O2 demands and substantial O2 deficits. We believe that enhanced splenic contraction may be of importance during competitions involving cross-country skiing, to regulate circulating Hb and enhance O2-carrying capacity, which may protect [Formula: see text] and increase O2 uptake.
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Affiliation(s)
- Pontus K Holmström
- Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Öyvind Karlsson
- Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Hampus Lindblom
- Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Kerry McGawley
- Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Erika K Schagatay
- Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Östersund, Sweden.,Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
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24
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Peng H, Kawamura T, Akiyama H, Chang L, Iwata R, Muraoka I. Effects of sex differences on breath-hold diving performance. Respir Physiol Neurobiol 2021; 293:103721. [PMID: 34153544 DOI: 10.1016/j.resp.2021.103721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 05/16/2021] [Accepted: 06/17/2021] [Indexed: 10/21/2022]
Abstract
PURPOSE The present study aimed to measure diving response, CO2 sensitivity and forced vital capacity in male and female breath-hold divers (BHDs), and to determine their effect on breath-hold diving performance. METHODS This study included 8 non-divers (NDs, 4 males and 4 females) and 15 BHDs (7 males and 8 females). For NDs, diving response was measured during breath-holding with facial immersion, whereas for BHDs CO2 sensitivity was also measured. RESULTS Compared to NDs, BHDs showed a prominent diving response. In BHDs, no statistically significant sex differences were observed in diving response and CO2 sensitivity. Furthermore, a positive correlation was found between performance and the % forced vital capacity in BHDs. CONCLUSION It was suggested that % forced vital capacity contributed more significantly to performance than diving response and CO2 sensitivity. Furthermore, the higher performance of male divers compared to female divers may be due to the % forced vital capacity rather than the diving response and CO2 sensitivity.
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Affiliation(s)
- Heng Peng
- Graduate School of Sport Sciences, Waseda University, 2-579-15 Mikajima, Tokorozawa-city, Saitama, 359-1192, Japan.
| | - Takuji Kawamura
- Waseda Institute for Sport Sciences, 2-579-15 Mikajima, Tokorozawa-city, Saitama, 359-1192, Japan
| | - Hiroshi Akiyama
- National Institutes of Biomedical Innovation, Health and Nutrition, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8636, Japan
| | - Lili Chang
- Graduate School of Sport Sciences, Waseda University, 2-579-15 Mikajima, Tokorozawa-city, Saitama, 359-1192, Japan
| | - Risa Iwata
- Japan Institute of Sport Sciences, 3-15-1 Nishigaoka, Kita-ku, Tokyo, 115-0056, Japan
| | - Isao Muraoka
- Faculty of Sport Sciences, Waseda University, 2-579-15 Mikajima, Tokorozawa-city, Saitama, 359-1192, Japan
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25
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Patrician A, Dujić Ž, Spajić B, Drviš I, Ainslie PN. Breath-Hold Diving - The Physiology of Diving Deep and Returning. Front Physiol 2021; 12:639377. [PMID: 34093221 PMCID: PMC8176094 DOI: 10.3389/fphys.2021.639377] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 04/07/2021] [Indexed: 11/13/2022] Open
Abstract
Breath-hold diving involves highly integrative physiology and extreme responses to both exercise and asphyxia during progressive elevations in hydrostatic pressure. With astonishing depth records exceeding 100 m, and up to 214 m on a single breath, the human capacity for deep breath-hold diving continues to refute expectations. The physiological challenges and responses occurring during a deep dive highlight the coordinated interplay of oxygen conservation, exercise economy, and hyperbaric management. In this review, the physiology of deep diving is portrayed as it occurs across the phases of a dive: the first 20 m; passive descent; maximal depth; ascent; last 10 m, and surfacing. The acute risks of diving (i.e., pulmonary barotrauma, nitrogen narcosis, and decompression sickness) and the potential long-term medical consequences to breath-hold diving are summarized, and an emphasis on future areas of research of this unique field of physiological adaptation are provided.
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Affiliation(s)
- Alexander Patrician
- Center for Heart, Lung & Vascular Health, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Željko Dujić
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| | - Boris Spajić
- Faculty of Kinesiology, University of Zagreb, Zagreb, Croatia
| | - Ivan Drviš
- Faculty of Kinesiology, University of Zagreb, Zagreb, Croatia
| | - Philip N Ainslie
- Center for Heart, Lung & Vascular Health, University of British Columbia Okanagan, Kelowna, BC, Canada
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26
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Schagatay E, Holmström P, Mulder E, Limbu P, Schagatay FS, Engan H, Lodin-Sundström A. Spleen Volume and Contraction During Apnea in Mt. Everest Climbers and Everest Base Camp Trekkers. High Alt Med Biol 2021; 21:84-91. [PMID: 32182148 DOI: 10.1089/ham.2019.0028] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The human spleen can contract and transiently boost the blood with stored erythrocytes. We measured spleen volume and contraction during apneas in two groups, each containing 12 Caucasian participants (each 3 women): one group planning to summit Mt. Everest (8848 m; "Climbers") and another trekking to Everest Base Camp (5300 m; "Trekkers"). Tests were done in Kathmandu (1370 m) 1-3 days after arrival, before the Climb/Trek. Age, height, weight, vital capacity, resting heart rate, and arterial oxygen saturation were similar between groups (not significant). After 15 minutes of sitting rest, all participants performed a 1-minute apnea and, after 2 minutes of rest, 1 maximal duration apnea was performed. Six of the climbers did a third apnea and hemoglobin concentration (Hb) was measured. Three axial spleen diameters were measured by ultrasonic imaging before and after the apneas for spleen volume calculation. Mean (standard deviation) baseline spleen volume was larger in Climbers [367 (181) mL] than in Trekkers [228 (70) mL; p = 0.022]. Spleen contraction occurred during apneas in both groups, with about twice the magnitude in Climbers. Three apneas in six of the Climbers resulted in a spleen volume reduction from 348 (145) to 202 (91) mL (p = 0.005) and an Hb elevation from 147.9 (13.1) to 153.3 (11.3) g/L (p = 0.024). Maximal apneic duration was longer in Climbers [88 (23) seconds vs. 67 (18) seconds in Trekkers; p = 0.023]. We concluded that a large spleen characterizes Climbers, suggesting that spleen function may be important for high-altitude climbing performance.
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Affiliation(s)
- Erika Schagatay
- Department of Health Sciences, Mid Sweden University, Östersund, Sweden.,Swedish Winter Sports Research Centre, Mid Sweden University, Ostersund, Sweden
| | - Pontus Holmström
- Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Eric Mulder
- Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Prakash Limbu
- Department of Clinical Physiology, Nepalese Army Institute of Health Sciences, Kathmandu, Nepal
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27
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Physiology, pathophysiology and (mal)adaptations to chronic apnoeic training: a state-of-the-art review. Eur J Appl Physiol 2021; 121:1543-1566. [PMID: 33791844 PMCID: PMC8144079 DOI: 10.1007/s00421-021-04664-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 03/04/2021] [Indexed: 02/08/2023]
Abstract
Breath-hold diving is an activity that humans have engaged in since antiquity to forage for resources, provide sustenance and to support military campaigns. In modern times, breath-hold diving continues to gain popularity and recognition as both a competitive and recreational sport. The continued progression of world records is somewhat remarkable, particularly given the extreme hypoxaemic and hypercapnic conditions, and hydrostatic pressures these athletes endure. However, there is abundant literature to suggest a large inter-individual variation in the apnoeic capabilities that is thus far not fully understood. In this review, we explore developments in apnoea physiology and delineate the traits and mechanisms that potentially underpin this variation. In addition, we sought to highlight the physiological (mal)adaptations associated with consistent breath-hold training. Breath-hold divers (BHDs) are evidenced to exhibit a more pronounced diving-response than non-divers, while elite BHDs (EBHDs) also display beneficial adaptations in both blood and skeletal muscle. Importantly, these physiological characteristics are documented to be primarily influenced by training-induced stimuli. BHDs are exposed to unique physiological and environmental stressors, and as such possess an ability to withstand acute cerebrovascular and neuronal strains. Whether these characteristics are also a result of training-induced adaptations or genetic predisposition is less certain. Although the long-term effects of regular breath-hold diving activity are yet to be holistically established, preliminary evidence has posed considerations for cognitive, neurological, renal and bone health in BHDs. These areas should be explored further in longitudinal studies to more confidently ascertain the long-term health implications of extreme breath-holding activity.
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Lodin-Sundström A, Holmström P, Ekstam M, Söderberg D, Schagatay E. Splenic contraction is enhanced by exercise at simulated high altitude. Eur J Appl Physiol 2021; 121:1725-1732. [PMID: 33683439 PMCID: PMC8144132 DOI: 10.1007/s00421-021-04637-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 02/09/2021] [Indexed: 11/30/2022]
Abstract
Purpose Splenic contraction increases circulating hemoglobin (Hb) with advantages during hypoxia. As both hypoxia and exercise have been shown to be important separate triggers of splenic contraction we aimed to investigate if the spleen response to simulated high altitude (HA) is enhanced by superimposing exercise. Method Fourteen healthy volunteers (seven females) performed the following protocol in a normobaric environment sitting on an ergometer cycle: 20 min rest in normoxia; 20 min rest while breathing hypoxic gas simulating an altitude of 3500 m; 10 min exercise at an individually set intensity while breathing the hypoxic gas; 20 min rest in hypoxia; and finally 20 min rest in normoxia. Spleen measurements were collected by ultrasonic imaging and venous Hb measured at the end of each intervention. Result Mean ± SD baseline spleen volume during normoxic rest was 280 ± 107 mL, the volume was reduced by 22% during rest in hypoxia to 217 ± 92 mL (p < 0.001) and by 33% during exercise in hypoxia (189 mL; p < 0.001). Hb was 140.7 ± 7.0 g/L during normoxic rest and 141.3 ± 7.4 g/L during hypoxic rest (NS), but increased by 5.3% during hypoxic exercise (148.6 ± 6.3 g/L; p < 0.001). Spleen volume and Hb were stepwise changed back to baseline at cessation of exercise and return to normoxia. Conclusion Splenic contraction is induced by hypoxia and further enhanced by superimposing exercise, and reduced when exercise ceases, in a step-wise manner, showing that the tonic but partial contraction observed in long-term field expeditions to HA may occur also in the short term. This “graded response” may be beneficial during acclimatization to HA, to cope with moderate chronic hypoxia during rest while allowing additional enhancement of oxygen carrying capacity to overcome short bouts of extreme hypoxia caused by exercise.
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Affiliation(s)
- Angelica Lodin-Sundström
- Department of Health Sciences, Mid Sweden University, Östersund, Sweden. .,Environmental Physiology Group, Department of Nursing Science, Mid Sweden University, Holmgatan 10, 85170, Sundsvall, Sweden.
| | - Pontus Holmström
- Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Marcus Ekstam
- Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Daniel Söderberg
- Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Erika Schagatay
- Department of Health Sciences, Mid Sweden University, Östersund, Sweden.,Swedish Winter Sports Research Centre, Östersund, Sweden
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29
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García I, Drobnic F, Arrillaga B, Pons V, Viscor G. Lung capacity and alveolar gas diffusion in aquatic athletes: Implications for performance and health. APUNTS SPORTS MEDICINE 2021. [DOI: 10.1016/j.apunsm.2020.100339] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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30
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Holmström PK, Bird JD, Thrall SF, Kalker A, Herrington BA, Soriano JE, Mann LM, Rampuri ZH, Brutsaert TD, Karlsson Ø, Sherpa MT, Schagatay EKA, Day TA. The effects of high altitude ascent on splenic contraction and the diving response during voluntary apnoea. Exp Physiol 2020; 106:160-174. [DOI: 10.1113/ep088571] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 09/03/2020] [Indexed: 12/30/2022]
Affiliation(s)
| | - Jordan D. Bird
- Department of Biology Faculty of Science and Technology Mount Royal University Calgary Alberta Canada
| | - Scott F. Thrall
- Department of Biology Faculty of Science and Technology Mount Royal University Calgary Alberta Canada
| | - Ann Kalker
- Department of Biology Faculty of Science and Technology Mount Royal University Calgary Alberta Canada
- Radboud University Nijmegen Netherlands
| | - Brittney A. Herrington
- Department of Biology Faculty of Science and Technology Mount Royal University Calgary Alberta Canada
| | - Jan E. Soriano
- Department of Biology Faculty of Science and Technology Mount Royal University Calgary Alberta Canada
| | - Leah M. Mann
- Department of Biology Faculty of Science and Technology Mount Royal University Calgary Alberta Canada
| | - Zahrah H. Rampuri
- Department of Biology Faculty of Science and Technology Mount Royal University Calgary Alberta Canada
| | - Tom D. Brutsaert
- Department of Exercise Science Syracuse University Syracuse NY USA
| | - Øyvind Karlsson
- Swedish Winter Sports Research Centre Mid Sweden University Östersund Sweden
| | | | - Erika K. A. Schagatay
- Department of Health Sciences Mid Sweden University Östersund Sweden
- Swedish Winter Sports Research Centre Mid Sweden University Östersund Sweden
| | - Trevor A. Day
- Department of Biology Faculty of Science and Technology Mount Royal University Calgary Alberta Canada
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31
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Engan H, Patrician A, Lodin-Sundström A, Johansson H, Melin M, Schagatay E. Spleen contraction and Hb elevation after dietary nitrate intake. J Appl Physiol (1985) 2020; 129:1324-1329. [PMID: 33031018 DOI: 10.1152/japplphysiol.00236.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ingestion of dietary nitrate ([Formula: see text]) is associated with improved exercise tolerance and reduced oxygen (O2) cost of exercise, ascribed to enhanced mitochondrial efficiency, muscle contractile function, or other factors. Nitrate ingestion has also been found to attenuate the reduction in arterial oxygen saturation ([Formula: see text]) during apnea and to prolong apneic duration. The spleen serves as a dynamic blood pool expelling erythrocytes into the circulation during apnea, and [Formula: see text] and nitric oxide donors may induce vasoactive effects in the mesenteric and splanchnic circulation. Our aim was to investigate the effect of ingestion of concentrated organic [Formula: see text]-rich beetroot juice (BR) on spleen volume and spleen contraction during apnea, and the resulting hemoglobin (Hb) concentration. Eight volunteers performed two apneas of submaximal and maximal duration during prone rest ∼2.5 h after ingesting 70 mL of BR (∼5 mmol [Formula: see text]) or placebo (PL; ∼0.003 mmol [Formula: see text]), on separate days in weighted order. Heart rate and [Formula: see text] were monitored continuously and spleen diameters were measured every minute for triaxial volume calculation. Capillary Hb samples were collected at baseline and after the maximal apnea. Baseline spleen volume was reduced by 66 mL after BR ingestion (22.9%; P = 0.026) and Hb was elevated (+3.0%; P = 0.015). During apneas, spleen contraction and Hb increase were similar between BR and PL conditions (NS). The study shows that dietary [Formula: see text]reduces spleen volume at rest, resulting in increased Hb. This spleen-induced Hb elevation following [Formula: see text] ingestions represents a novel mechanism that could enhance performance in conditions involving exercise, apnea, and hypoxia.NEW & NOTEWORTHY This is the first study to examine changes of spleen volume and circulating Hb following dietary [Formula: see text] supplementation. After dietary [Formula: see text] ingestion, the spleen volume at rest was reduced and Hb was elevated. The spleen contains a dynamic red blood cell reservoir, which can be mobilized and facilitate oxygen transport during various types of physiological stress. This study has revealed an additional, previously unexplored mechanism possibly contributing to the ergogenic effects of dietary [Formula: see text].
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Affiliation(s)
- Harald Engan
- Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Östersund, Sweden.,Unicare Rehabilitation Norway, Oslo, Norway
| | - Alexander Patrician
- Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Östersund, Sweden.,Centre for Heart, Lung & Vascular Health, University of British Columbia Okanagan, Kelowna, Canada
| | - Angelica Lodin-Sundström
- Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Östersund, Sweden.,Department of Nursing Sciences, Mid Sweden University, Sundsvall, Sweden
| | - Hampus Johansson
- Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Maja Melin
- Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Erika Schagatay
- Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Östersund, Sweden.,Swedish Winter Sports Research Centre, Mid Sweden University, Östersund, Sweden
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Spleen contraction elevates hemoglobin concentration at high altitude during rest and exercise. Eur J Appl Physiol 2020; 120:2693-2704. [PMID: 32910244 PMCID: PMC7674357 DOI: 10.1007/s00421-020-04471-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 08/10/2020] [Indexed: 01/28/2023]
Abstract
PURPOSE Hypoxia and exercise are known to separately trigger spleen contraction, leading to release of stored erythrocytes. We studied spleen volume and hemoglobin concentration (Hb) during rest and exercise at three altitudes. METHODS Eleven healthy lowlanders did a 5-min modified Harvard step test at 1370, 3700 and 4200 m altitude. Spleen volume was measured via ultrasonic imaging and capillary Hb with Hemocue during rest and after the step test, and arterial oxygen saturation (SaO2), heart rate (HR), expiratory CO2 (ETCO2) and respiratory rate (RR) across the test. RESULTS Resting spleen volume was reduced with increasing altitude and further reduced with exercise at all altitudes. Mean (SE) baseline spleen volume at 1370 m was 252 (20) mL and after exercise, it was 199 (15) mL (P < 0.01). At 3700 m, baseline spleen volume was 231 (22) mL and after exercise 166 (12) mL (P < 0.05). At 4200 m baseline volume was 210 (23) mL and after exercise 172 (20) mL (P < 0.05). After 10 min, spleen volume increased to baseline at all altitudes (NS). Baseline Hb increased with altitude from 138.9 (6.1) g/L at 1370 m, to 141.2 (4.1) at 3700 m and 152.4 (4.0) at 4200 m (P < 0.01). At all altitudes Hb increased from baseline during exercise to 146.8 (5.7) g/L at 1370 m, 150.4 (3.8) g/L at 3700 m and 157.3 (3.8) g/L at 4200 m (all P < 0.05 from baseline). Hb had returned to baseline after 10 min rest at all altitudes (NS). The spleen-derived Hb elevation during exercise was smaller at 4200 m compared to 3700 m (P < 0.05). Cardiorespiratory variables were also affected by altitude during both rest and exercise. CONCLUSIONS The spleen contracts and mobilizes stored red blood cells during rest at high altitude and contracts further during exercise, to increase oxygen delivery to tissues during acute hypoxia. The attenuated Hb response to exercise at the highest altitude is likely due to the greater recruitment of the spleen reserve during rest, and that maximal spleen contraction is reached with exercise.
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García I, Drobnic F, Pons V, Viscor G. Changes in Lung Diffusing Capacity of Elite Artistic Swimmers During Training. Int J Sports Med 2020; 42:227-233. [PMID: 32851635 DOI: 10.1055/a-1212-1020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Artistic swimmers (AS) are exposed to repeated apnoeas in the aquatic environment during high intensity exercise provoking specific physiological responses to training, apnoea, and immersion. This study aimed to evaluate the changes in lung diffusing capacity in AS pre-, mid- and post-training in a combined session of apnoeic swimming, figures and choreography. Eleven elite female AS from the Spanish national team were the study's participants. The single-breath method was used to measure lung diffusing capacity for carbon monoxide (DLCO) and one-way repeated measures ANOVA was utilized to evaluate the statistical analysis. Basal values of DLCO were higher than normal for their age and height (33.6±4.9 mL·min-1·mmHg-1; 139±19%) and there were a significant interaction between DLCO and AS training (ŋ2 p=0.547). After the apnoeic swimming (mid-training) there was an increase in DLCO from basal to 36.7±7.3 mL·min-1·mmHg-1 (p=0.021), and after the figures and choreography (post-training) there was a decrease compared to mid-training (32.3±4.6 mL·min-1·mmHg-1, p=0.013). Lung diffusing capacity changes occur during AS training, including a large increase after apnoeic swimming. There were no differences in lung diffusing capacity from pre- to post-training, although large inter-individual variability was observed.
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Affiliation(s)
- Iker García
- Secció de Fisiologia, Departament de Biologia Cel lular, Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain.,Departament de Fisiologia i Nutricio, Centre d'Alt Rendiment, Sant Cugat Del Valles, Spain
| | | | - Victoria Pons
- Departament de Fisiologia i Nutricio, Centre d'Alt Rendiment, Sant Cugat Del Valles, Spain
| | - Ginés Viscor
- Secció de Fisiologia, Departament de Biologia Cel lular, Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
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Holmström P, Mulder E, Starfelt V, Lodin-Sundström A, Schagatay E. Spleen Size and Function in Sherpa Living High, Sherpa Living Low and Nepalese Lowlanders. Front Physiol 2020; 11:647. [PMID: 32695011 PMCID: PMC7339931 DOI: 10.3389/fphys.2020.00647] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 05/20/2020] [Indexed: 11/13/2022] Open
Abstract
High-altitude (HA) natives have evolved some beneficial responses leading to superior work capacity at HA compared to native lowlanders. Our aim was to study two responses potentially protective against hypoxia: the spleen contraction elevating hemoglobin concentration (Hb) and the cardiovascular diving response in Sherpa highlanders, compared to lowlanders. Male participants were recruited from three groups: (1) 21 Sherpa living at HA (SH); (2) seven Sherpa living at low altitude (SL); and (3) ten native Nepalese lowlanders (NL). They performed three apneas spaced by a two-min rest at low altitude (1370 m). Their peripheral oxygen saturation (SpO2), heart rate (HR), and spleen volume were measured across the apnea protocol. Spleen volume at rest was 198 ± 56 mL in SH and 159 ± 35 mL in SL (p = 0.047). The spleen was larger in Sherpa groups compared to the 129 ± 22 mL in NL (p < 0.001 compared to SH; p = 0.046 compared to SL). Spleen contraction occurred in all groups during apnea, but it was greater in Sherpa groups compared to NL (p < 0.001). HR was lower in Sherpa groups compared to NL both during rest (SL: p < 0.001; SH: p = 0.003) and during maximal apneas (SL: p < 0.001; SH: p = 0.06). The apnea-induced HR reduction was 8 ± 8% in SH, 10 ± 4% in SL (NS), and 18 ± 6% in NL (SH: p = 0.005; SL: p = 0.021 compared to NL). Resting SpO2 was similar in all groups. The progressively decreasing baseline spleen size across SH, SL, and NL suggests a role of the spleen at HA and further that both genetic predisposition and environmental exposure determine human spleen size. The similar HR responses of SH and SL suggest that a genetic component is involved in determining the cardiovascular diving response.
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Affiliation(s)
- Pontus Holmström
- Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Eric Mulder
- Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Victor Starfelt
- Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Angelica Lodin-Sundström
- Department of Health Sciences, Mid Sweden University, Östersund, Sweden.,Department of Nursing Sciences, Mid Sweden University, Sundsvall, Sweden
| | - Erika Schagatay
- Department of Health Sciences, Mid Sweden University, Östersund, Sweden.,Swedish Winter Sports Research Centre, Mid Sweden University, Östersund, Sweden
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Elia A, Barlow MJ, Wilson OJ, O'Hara JP. Splenic responses to a series of repeated maximal static and dynamic apnoeas with whole-body immersion in water. Exp Physiol 2020; 106:338-349. [PMID: 32421235 DOI: 10.1113/ep088404] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 05/13/2020] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Splenic contractions occur in response to apnoea-induced hypoxia with and without face immersion in water. However, the splenic responses to a series of static or dynamic apnoeas with whole-body water immersion in non-divers and elite breath-hold divers are unknown. What is the main finding and its importance? Static and dynamic apnoeas were equally effective in stimulating splenic contractions across non-divers and elite breath-hold divers. These findings demonstrate that the magnitude of the splenic response is largely dictated by the degree of the hypoxemic stress encountered during voluntary apnoeic epochs. ABSTRACT Splenic contractions occur in response to apnoea-induced hypoxia with and without facial water immersion. However, the splenic responses to a series of static (STA) or dynamic (DYN) apnoeas with whole-body water immersion in non-divers (NDs) and elite breath-hold divers (EBHDs) are unknown. EBHD (n = 8), ND (n = 10) and control participants (n = 8) were recruited. EBHD and ND performed a series of five maximal DYN or STA on separate occasions. Control performed a static eupnoeic (STE) protocol to control against any effects of water immersion and diurnal variation on splenic volume and haematology. Heart rate (HR) and peripheral oxygen saturation (SpO2 ) were monitored for 30 s after each apnoea. Pre- and post-apnoeic splenic volumes were quantified ultrasonically, and blood samples were drawn for haematology. For EBHD and ND end-apnoeic HR was higher (P < 0.001) and SpO2 was lower in DYN (P = 0.024) versus STA. EBHD attained lower end-apnoeic SpO2 during DYN and STA than NDs (P < 0.001). Splenic contractions occurred following DYN (EBHD, -47 ± 6%; ND, -37 ± 4%; P < 0.001) and STA (EBHD, -26 ± 4%; ND, -26 ± 8%; P < 0.01). DYN-associated splenic contractions were greater than STA in EBHD only (P = 0.042). Haemoglobin concentrations were higher following DYN only (EBHD, +5 ± 8g/L , +4 ± 2%; ND, +8 ± 3 g/L , +4.9 ± 3%; P = 0.019). Haematocrit remained unchanged after each protocol. There were no between group differences in post-apnoeic splenic volume or haematology. In both groups, splenic contractions occurred in response to STA and DYN when combined with whole-body immersion. DYN apnoeas, were effective at increasing haemoglobin concentrations but not STA apnoeas. Thus, the magnitude of the splenic response relates to the hypoxemic stress encountered during apnoeic epochs.
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Affiliation(s)
- Antonis Elia
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK.,Division of Environmental Physiology, School of Chemistry, Bioengineering and Health, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Matthew J Barlow
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK
| | - Oliver J Wilson
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK
| | - John P O'Hara
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK
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Lung Diffusion in a 14-Day Swimming Altitude Training Camp at 1850 Meters. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17103501. [PMID: 32429560 PMCID: PMC7277217 DOI: 10.3390/ijerph17103501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 05/11/2020] [Accepted: 05/14/2020] [Indexed: 12/19/2022]
Abstract
Swimming exercise at sea level causes a transient decrease in lung diffusing capacity for carbon monoxide (DLCO). The exposure to hypobaric hypoxia can affect lung gas exchange, and hypoxic pulmonary vasoconstriction may elicit pulmonary oedema. The purpose of this study is to evaluate whether there are changes in DLCO during a 14-day altitude training camp (1850 m) in elite swimmers and the acute effects of a combined training session of swimming in moderate hypoxia and 44-min cycling in acute normobaric severe hypoxia (3000 m). Participants were eight international level swimmers (5 females and 3 males; 17–24 years old; 173.5 ± 5.5 cm; 64.4 ± 5.3 kg) with a training volume of 80 km per week. The single-breath method was used to measure the changes in DLCO and functional gas exchange parameters. No changes in DLCO after a 14-day altitude training camp at 1850 m were detected but a decrease in alveolar volume (VA; 7.13 ± 1.61 vs. 6.50 ± 1.59 L; p = 0.005; d = 0.396) and an increase in the transfer coefficient of the lung for carbon monoxide (KCO; 6.23 ± 1.03 vs. 6.83 ± 1.31 mL·min−1·mmHg−1·L−1; p = 0.038; d = 0.509) after the altitude camp were observed. During the acute hypoxia combined session, there were no changes in DLCO after swimming training at 1850 m, but there was a decrease in DLCO after cycling at a simulated altitude of 3000 m (40.6 ± 10.8 vs. 36.8 ± 11.2 mL·min−1·mmHg−1; p = 0.044; d = 0.341). A training camp at moderate altitude did not alter pulmonary diffusing capacity in elite swimmers, although a cycling session at a higher simulated altitude caused a certain degree of impairment of the alveolar–capillary gas exchange.
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Turning the Oxygen Dial: Balancing the Highs and Lows. Trends Cell Biol 2020; 30:516-536. [PMID: 32386878 DOI: 10.1016/j.tcb.2020.04.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/02/2020] [Accepted: 04/08/2020] [Indexed: 02/06/2023]
Abstract
Oxygen is both vital and toxic to life. Molecular oxygen is the most used substrate in the human body and is required for several hundred diverse biochemical reactions. The discovery of the PHD-HIF-pVHL system revolutionized our fundamental understanding of oxygen sensing and cellular adaptations to hypoxia. It deepened our knowledge of the biochemical underpinnings of numerous diseases, ranging from anemia to cancer. Cellular dysfunction and tissue pathology can result from a mismatch of oxygen supply and demand. Recent work has shown that mitochondrial disease models display tissue hyperoxia and that disease pathology can be reversed by normalization of excess oxygen, suggesting that certain disease states can potentially be treated by modulating oxygen levels. In this review, we describe cellular and organismal mechanisms of oxygen sensing and adaptation. We provide a revitalized framework for understanding pathologies of too little or too much oxygen.
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38
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Robertson C, Lodin-Sundström A, O'Hara J, King R, Wainwright B, Barlow M. Effects of Pre-race Apneas on 400-m Freestyle Swimming Performance. J Strength Cond Res 2020; 34:828-837. [DOI: 10.1519/jsc.0000000000002711] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Garnitschnig L, Weinzirl J, Andrae L, Scheffers T, Ostermann T, Heusser P. Postprandial dynamics of splenic volume in healthy volunteers. Physiol Rep 2020; 8:e14319. [PMID: 31981412 PMCID: PMC6981305 DOI: 10.14814/phy2.14319] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Throughout the history of medicine, many functions have been attributed to the spleen and numerous researchers have focused on a postulated digestive function. Beginning in 1825, systematic animal studies showed evidence for a postprandial increase in splenic volume (SV) with a peak 30 min to five hours after food intake. Since the introduction of imaging techniques, two studies have been conducted on humans, revealing a decrease in SV 30 to 45 min postprandially. The aim of this study was to examine possible postprandial changes in SV over a period of seven hours. The ethics-approved, randomized crossover study included 10 healthy volunteers, who received a standardized meal (3,600 kJ) on one study day and fasted on the other. Sonographic measurements were obtained at six measurement points on each day. Thirty minutes after the meal, SV increased significantly by 38.2 ± 51.2 cm3 (17.3%; p = .04) compared to the baseline measurement and decreased gradually afterward. In males, SV 30 min after the meal was 70.2 ± 21.6 cm3 higher (p = .002) compared to the fasting condition and 60 min later it was still significantly increased. The apparent SV increase after food intake is discussed in relation to hemodynamic changes in the splanchnic region. It seems plausible that the spleen has a rhythmic and regulative function within the portal system, something which warrants further research and should be taken more into account in nutritional physiology.
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Affiliation(s)
- Lydia Garnitschnig
- Institute for Integrative MedicineFaculty of HealthWitten/Herdecke UniversityHerdeckeGermany
| | - Johannes Weinzirl
- Institute for Integrative MedicineFaculty of HealthWitten/Herdecke UniversityHerdeckeGermany
| | - Lukas Andrae
- Department of Internal MedicineCommunity Hospital HerdeckeHerdeckeGermany
| | - Tom Scheffers
- Institute for Integrative MedicineFaculty of HealthWitten/Herdecke UniversityHerdeckeGermany
| | - Thomas Ostermann
- Institute for Integrative MedicineFaculty of HealthWitten/Herdecke UniversityHerdeckeGermany
| | - Peter Heusser
- Institute for Integrative MedicineFaculty of HealthWitten/Herdecke UniversityHerdeckeGermany
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Van Hove O, Van Muylem A, Andrianopoulos V, Leduc D, Feipel V, Deboeck G, Bonnechère B. The use of cognitive mobile games to assess the interaction of cognitive function and breath-hold. Respir Physiol Neurobiol 2019; 274:103359. [PMID: 31812789 DOI: 10.1016/j.resp.2019.103359] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 12/02/2019] [Accepted: 12/04/2019] [Indexed: 01/22/2023]
Abstract
The relationship between cognitive function and breath-holding time is in need of further investigation. We aim to determine whether cognitive mobile games (CMG) are sensitive enough to assess the link between cognition and breath-holding time in non-trained subjects. Thirty-one healthy subjects participated in this study. A set of 3 short CMG: Must Sort (response control), Rush Back (attention, working memory) and True Color (mental flexibility, inhibition) was used. Apneic time was recorded in three different conditions: Total Lung Capacity (TLC): 88 ± 35 s, Functional Residual Capacity (FRC): 49 ± 17 s, and Residual Volume (RV): 32 ± 14 s. In males, breath-holding time at RV was correlated with True Color (r = 0.48) and Rush Back (r = 0.65) and at TLC with True Color (r = 0.45). In women, breath-holding time at TLC and FRC was inversely correlated with Must Sort (r = -0.59 and r = -0.49 respectively). Males and females appeared to differ in their use of cognitive resources during different breath-holding conditions.
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Affiliation(s)
- Olivier Van Hove
- Chest and Thoracic Surgery Service, Erasme Hospital, Brussels, Belgium
| | | | - Vasileios Andrianopoulos
- Institute for Pulmonary Rehabilitation Research, Schoen Klinik Berchtesgadener Land, Schoenau am Koenigssee, Germany
| | - Dimitri Leduc
- Department of Pneumology, Erasme Hospital, Brussels, Belgium; Laboratory of Cardiorespiratory Physiology, Université Libre de Bruxelles, Brussels, Belgium
| | - Véronique Feipel
- Laboratory of Functional Anatomy, Université Libre de Bruxelles, Brussels, Belgium
| | - Gaël Deboeck
- Research Unit in Cardio-respiratory Physiology, Université Libre de Bruxelles, Brussels, Belgium
| | - Bruno Bonnechère
- Centre de Recherche en Epidémiologie, Biostatistiques et Recherche Clinique, Ecole de Santé Publique, Université libre de Bruxelles, Brussels, Belgium; Department of Electronics and Informatics - ETRO, Vrije Universiteit Brussel, Brussels, Belgium.
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41
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Skeletal muscle, haematological and splenic volume characteristics of elite breath-hold divers. Eur J Appl Physiol 2019; 119:2499-2511. [PMID: 31542805 PMCID: PMC6858395 DOI: 10.1007/s00421-019-04230-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 08/29/2019] [Indexed: 11/25/2022]
Abstract
Purpose The aim of the study was to provide an evaluation of the oxygen transport, exchange and storage capacity of elite breath-hold divers (EBHD) compared with non-divers (ND). Methods Twenty-one healthy males’ (11 EBHD; 10 ND) resting splenic volumes were assessed by ultrasound and venous blood drawn for full blood count analysis. Percutaneous skeletal muscle biopsies were obtained from the m. vastus lateralis to measure capillarisation, and fibre type-specific localisation and distribution of myoglobin and mitochondrial content using quantitative immunofluorescence microscopy. Results Splenic volume was not different between groups. Reticulocytes, red blood cells and haemoglobin concentrations were higher (+ 24%, p < 0.05; + 9%, p < 0.05; + 3%, p < 0.05; respectively) and mean cell volume was lower (− 6.5%, p < 0.05) in the EBHD compared with ND. Haematocrit was not different between groups. Capillary density was greater (+ 19%; p < 0.05) in the EBHD. The diffusion distance (R95) was lower in type I versus type II fibres for both groups (EBHD, p < 0.01; ND, p < 0.001), with a lower R95 for type I fibres in the EBHD versus ND (− 13%, p < 0.05). Myoglobin content was higher in type I than type II fibres in EBHD (+ 27%; p < 0.01) and higher in the type I fibres of EBHD than ND (+ 27%; p < 0.05). No fibre type differences in myoglobin content were observed in ND. Mitochondrial content was higher in type I than type II fibres in EBHD (+ 35%; p < 0.05), with no fibre type differences in ND or between groups. Conclusions In conclusion, EBDH demonstrate enhanced oxygen storage in both blood and skeletal muscle and a more efficient oxygen exchange capacity between blood and skeletal muscle versus ND.
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Holmström P, Mulder E, Sundström AL, Limbu P, Schagatay E. The Magnitude of Diving Bradycardia During Apnea at Low-Altitude Reveals Tolerance to High Altitude Hypoxia. Front Physiol 2019; 10:1075. [PMID: 31507443 PMCID: PMC6714063 DOI: 10.3389/fphys.2019.01075] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 08/05/2019] [Indexed: 11/13/2022] Open
Abstract
Acute mountain sickness (AMS) is a potentially life-threatening illness that may develop during exposure to hypoxia at high altitude (HA). Susceptibility to AMS is highly individual, and the ability to predict it is limited. Apneic diving also induces hypoxia, and we aimed to investigate whether protective physiological responses, i.e., the cardiovascular diving response and spleen contraction, induced during apnea at low-altitude could predict individual susceptibility to AMS. Eighteen participants (eight females) performed three static apneas in air, the first at a fixed limit of 60 s (A1) and two of maximal duration (A2-A3), spaced by 2 min, while SaO2, heart rate (HR) and spleen volume were measured continuously. Tests were conducted in Kathmandu (1470 m) before a 14 day trek to mount Everest Base Camp (5360 m). During the trek, participants reported AMS symptoms daily using the Lake Louise Questionnaire (LLQ). The apnea-induced HR-reduction (diving bradycardia) was negatively correlated with the accumulated LLQ score in A1 (r s = -0.628, p = 0.005) and A3 (r s = -0.488, p = 0.040) and positively correlated with SaO2 at 4410 m (A1: r = 0.655, p = 0.003; A2: r = 0.471, p = 0.049; A3: r = 0.635, p = 0.005). Baseline spleen volume correlated negatively with LLQ score (r s = -0.479, p = 0.044), but no correlation was found between apnea-induced spleen volume reduction with LLQ score (r s = 0.350, p = 0.155). The association between the diving bradycardia and spleen size with AMS symptoms suggests links between physiological responses to HA and apnea. Measuring individual responses to apnea at sea-level could provide means to predict AMS susceptibility prior to ascent.
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Affiliation(s)
- Pontus Holmström
- Department of Health Sciences, Mid Sweden University, Sundsvall, Sweden
| | - Eric Mulder
- Department of Health Sciences, Mid Sweden University, Sundsvall, Sweden
| | | | - Prakash Limbu
- Department of Clinical Physiology, Nepalese Army Institute of Health Sciences, Kathmandu, Nepal
| | - Erika Schagatay
- Department of Health Sciences, Mid Sweden University, Sundsvall, Sweden
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Bouten J, Caen K, Stautemas J, Lefevere F, Derave W, Lootens L, Van Eenoo P, Bourgois JG, Boone J. Eight weeks of static apnea training increases spleen volume but not acute spleen contraction. Respir Physiol Neurobiol 2019; 266:144-149. [PMID: 31009754 DOI: 10.1016/j.resp.2019.04.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 03/13/2019] [Accepted: 04/03/2019] [Indexed: 11/25/2022]
Abstract
Splenic contraction is an important response to acute apnea causing the release of red blood cells into blood circulation. Current literature shows higher spleen volumes and greater spleen contractions in trained apnea divers compared to untrained individuals, but the influence of training is presently unknown. Thirteen subjects daily performed five static apneas for 8 weeks. Before, halfway through and after the apnea training period, subjects performed five maximal breath-holds at the laboratory. Baseline values for and changes in splenic volume and hemoglobin ([Hb]) were assessed. Although baseline spleen volume had increased (from 241 ± 55 mL PRE to 299 ± 51 mL POST training, p = 0.007), the absolute spleen contraction (142 ± 52 mL PRE and 139 ± 34 mL POST training, p = 0.868) and the acute increase in [Hb] remained unchanged. The present study shows that apnea training can increase the size of the spleen but that eight weeks of training is not sufficient to elicit significant training adaptations on the acute response.
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Affiliation(s)
- Janne Bouten
- Department of Movement and Sports Sciences, Ghent University, Watersportlaan 2, 9000 Ghent, Belgium
| | - Kevin Caen
- Department of Movement and Sports Sciences, Ghent University, Watersportlaan 2, 9000 Ghent, Belgium
| | - Jan Stautemas
- Department of Movement and Sports Sciences, Ghent University, Watersportlaan 2, 9000 Ghent, Belgium
| | - Filip Lefevere
- Department of Movement and Sports Sciences, Ghent University, Watersportlaan 2, 9000 Ghent, Belgium
| | - Wim Derave
- Department of Movement and Sports Sciences, Ghent University, Watersportlaan 2, 9000 Ghent, Belgium
| | - Leen Lootens
- Doping Control Laboratory, Department of Clinical Chemistry, Microbiology and Immunology, Ghent University, Technologiepark Zwijnaarde 30, 9050 Ghent, Belgium
| | - Peter Van Eenoo
- Doping Control Laboratory, Department of Clinical Chemistry, Microbiology and Immunology, Ghent University, Technologiepark Zwijnaarde 30, 9050 Ghent, Belgium
| | - Jan G Bourgois
- Department of Movement and Sports Sciences, Ghent University, Watersportlaan 2, 9000 Ghent, Belgium; Centre of Sports Medicine, Ghent University, Ghent, Belgium
| | - Jan Boone
- Department of Movement and Sports Sciences, Ghent University, Watersportlaan 2, 9000 Ghent, Belgium.
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Bain AR, Drvis I, Dujic Z, MacLeod DB, Ainslie PN. Physiology of static breath holding in elite apneists. Exp Physiol 2019; 103:635-651. [PMID: 29512224 DOI: 10.1113/ep086269] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 03/02/2018] [Indexed: 12/16/2022]
Abstract
NEW FINDINGS What is the topic of this review? This review provides an up-to-date assessment of the physiology involved with extreme static dry-land breath holding in trained apneists. What advances does it highlight? We specifically highlight the recent findings involved with the cardiovascular, cerebrovascular and metabolic function during a maximal breath hold in elite apneists. ABSTRACT Breath-hold-related activities have been performed for centuries, but only recently, within the last ∼30 years, has it emerged as an increasingly popular competitive sport. In apnoea sport, competition relates to underwater distances or simply maximal breath-hold duration, with the current (oxygen-unsupplemented) static breath-hold record at 11 min 35 s. Remarkably, many ultra-elite apneists are able to suppress respiratory urges to the point where consciousness fundamentally limits a breath-hold duration. Here, arterial oxygen saturations as low as ∼50% have been reported. In such cases, oxygen conservation to maintain cerebral functioning is critical, where responses ascribed to the mammalian dive reflex, e.g. sympathetically mediated peripheral vasoconstriction and vagally mediated bradycardia, are central. In defence of maintaining global cerebral oxygen delivery during prolonged breath holds, the cerebral blood flow may increase by ∼100% from resting values. Interestingly, near the termination of prolonged dry static breath holds, recent studies also indicate that reductions in the cerebral oxidative metabolism can occur, probably attributable to the extreme hypercapnia and irrespective of the hypoxaemia. In this review, we highlight and discuss the recent data on the cardiovascular, metabolic and, particularly, cerebrovascular function in competitive apneists performing maximal static breath holds. The physiological adaptation and maladaptation with regular breath-hold training are also summarized, and future research areas in this unique physiological field are highlighted; particularly, the need to determine the potential long-term health impacts of extreme breath holding.
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Affiliation(s)
- Anthony R Bain
- Center for Heart, Lung and Vascular Health, University of British Columbia, Kelowna, BC, Canada.,Integrative Physiology, University of Colorado, Boulder, CO, USA
| | - Ivan Drvis
- Faculty of Kinesiology, University of Zagreb, Zagreb, Croatia
| | - Zeljko Dujic
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| | - David B MacLeod
- Human Pharmacology and Physiology Laboratory, Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Philip N Ainslie
- Center for Heart, Lung and Vascular Health, University of British Columbia, Kelowna, BC, Canada
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45
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Abstract
Breath-hold diving is practiced by recreational divers, seafood divers, military divers, and competitive athletes. It involves highly integrated physiology and extreme responses. This article reviews human breath-hold diving physiology beginning with an historical overview followed by a summary of foundational research and a survey of some contemporary issues. Immersion and cardiovascular adjustments promote a blood shift into the heart and chest vasculature. Autonomic responses include diving bradycardia, peripheral vasoconstriction, and splenic contraction, which help conserve oxygen. Competitive divers use a technique of lung hyperinflation that raises initial volume and airway pressure to facilitate longer apnea times and greater depths. Gas compression at depth leads to sequential alveolar collapse. Airway pressure decreases with depth and becomes negative relative to ambient due to limited chest compliance at low lung volumes, raising the risk of pulmonary injury called "squeeze," characterized by postdive coughing, wheezing, and hemoptysis. Hypoxia and hypercapnia influence the terminal breakpoint beyond which voluntary apnea cannot be sustained. Ascent blackout due to hypoxia is a danger during long breath-holds, and has become common amongst high-level competitors who can suppress their urge to breathe. Decompression sickness due to nitrogen accumulation causing bubble formation can occur after multiple repetitive dives, or after single deep dives during depth record attempts. Humans experience responses similar to those seen in diving mammals, but to a lesser degree. The deepest sled-assisted breath-hold dive was to 214 m. Factors that might determine ultimate human depth capabilities are discussed. © 2018 American Physiological Society. Compr Physiol 8:585-630, 2018.
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Lydon H, Hall C, Matar H, Dalton C, Chipman JK, Graham JS, Chilcott RP. The percutaneous toxicokinetics of VX in a damaged skin porcine model and the evaluation of WoundStat™ as a topical decontaminant. J Appl Toxicol 2017; 38:318-328. [PMID: 29023806 DOI: 10.1002/jat.3542] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 08/31/2017] [Accepted: 08/31/2017] [Indexed: 11/06/2022]
Abstract
This study used a damaged skin, porcine model to evaluate the in vivo efficacy of WoundStat™ for the decontamination of superficial, nerve agent-contaminated wounds. Anaesthetized animals were randomly assigned to either control (n = 7), no decontamination (n = 12) or WoundStat™ (n = 12) treatment groups. Pigs were exposed to a 5× LD50 dose of neat, radiolabelled S-[2-(diisopropylamino)ethyl]-O-ethyl methyl-phosphonothioate (VX; or equivalent volume of sterile saline for the control group) via an area of superficially damaged skin on the ear. WoundStat™ was applied at 30 seconds post-exposure to assigned animals. The VX contaminant (or saline) and decontaminant remained in place for the duration of the study (up to 6 hours). Physiological parameters and signs of intoxication were recorded during the exposure period. Skin and organ samples were taken post mortem for 14 C-VX distribution analyses. Blood samples were taken periodically for toxicokinetic and whole-blood acetylcholinesterase (AChE) activity analyses. VX exposure was accompanied by a rapid decrease in AChE activity in all animals, regardless of decontamination. However, decontamination significantly improved survival rate and time and reduced the severity of signs of intoxication. In addition, the distribution of 14 C-VX in key internal organs and post mortem blood samples was significantly lower in the WoundStat™ treatment group. This study demonstrates that WoundStat™ may be a suitable medical countermeasure for increasing both survival rate and time following VX exposure. The results also suggest that AChE activity is not a useful prognostic indicator.
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Affiliation(s)
- Helen Lydon
- CBRN & Chemical Toxicological Research Group, Centre for Radiation, Chemical and Environmental Hazards, Health Protection Agency (now Public Health England), Chilton, UK.,School of Biosciences, University of Birmingham, Edgbaston, UK
| | - Charlotte Hall
- CBRN & Chemical Toxicological Research Group, Centre for Radiation, Chemical and Environmental Hazards, Health Protection Agency (now Public Health England), Chilton, UK.,School of Biosciences, University of Birmingham, Edgbaston, UK
| | - Hazem Matar
- CBRN & Chemical Toxicological Research Group, Centre for Radiation, Chemical and Environmental Hazards, Health Protection Agency (now Public Health England), Chilton, UK.,Research Centre for Topical Drug Delivery and Toxicology, University of Hertfordshire, Hatfield, UK
| | - Christopher Dalton
- School of Biosciences, University of Birmingham, Edgbaston, UK.,Defence Science & Technology Laboratory, Porton, UK
| | - J Kevin Chipman
- School of Biosciences, University of Birmingham, Edgbaston, UK
| | - John S Graham
- Medical Toxicology Branch Analytical Toxicology Division, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, 21010, USA
| | - Robert P Chilcott
- CBRN & Chemical Toxicological Research Group, Centre for Radiation, Chemical and Environmental Hazards, Health Protection Agency (now Public Health England), Chilton, UK.,Research Centre for Topical Drug Delivery and Toxicology, University of Hertfordshire, Hatfield, UK
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47
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Desola J. Muerte súbita de origen no cardiológico durante el ejercicio. El modelo del disbarismo. Med Clin (Barc) 2017; 148:566-568. [DOI: 10.1016/j.medcli.2017.02.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 02/20/2017] [Accepted: 02/23/2017] [Indexed: 11/24/2022]
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48
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Schagatay E, Hubinette A, Lodin-Sundström A, Engan H, Stenfors N. Exercise induced hemoconcentration following spleen contraction in subjects with COPD. ACTA ACUST UNITED AC 2015. [DOI: 10.1186/s40749-015-0015-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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49
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Skow RJ, Day TA, Fuller JE, Bruce CD, Steinback CD. The ins and outs of breath holding: simple demonstrations of complex respiratory physiology. ADVANCES IN PHYSIOLOGY EDUCATION 2015; 39:223-231. [PMID: 26330043 DOI: 10.1152/advan.00030.2015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The physiology of breath holding is complex, and voluntary breath-hold duration is affected by many factors, including practice, psychology, respiratory chemoreflexes, and lung stretch. In this activity, we outline a number of simple laboratory activities or classroom demonstrations that illustrate the complexity of the integrative physiology behind breath-hold duration. These activities require minimal equipment and are easily adapted to small-group demonstrations or a larger-group inquiry format where students can design a protocol and collect and analyze data from their classmates. Specifically, breath-hold duration is measured during a number of maneuvers, including after end expiration, end inspiration, voluntary prior hyperventilation, and inspired hyperoxia. Further activities illustrate the potential contribution of chemoreflexes through rebreathing and repeated rebreathing after a maximum breath hold. The outcome measures resulting from each intervention are easily visualized and plotted and can comprise a comprehensive data set to illustrate and discuss complex and integrated cardiorespiratory physiology.
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Affiliation(s)
- Rachel J Skow
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada; and
| | - Trevor A Day
- Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada
| | - Jonathan E Fuller
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada; and
| | - Christina D Bruce
- Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada
| | - Craig D Steinback
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada; and
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50
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Comparative analysis of human ex vivo-generated platelets vs megakaryocyte-generated platelets in mice: a cautionary tale. Blood 2015; 125:3627-36. [PMID: 25852052 DOI: 10.1182/blood-2014-08-593053] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 03/30/2015] [Indexed: 02/06/2023] Open
Abstract
Thrombopoiesis is the process by which megakaryocytes release platelets that circulate as uniform small, disc-shaped anucleate cytoplasmic fragments with critical roles in hemostasis and related biology. The exact mechanism of thrombopoiesis and the maturation pathways of platelets released into the circulation remain incompletely understood. We showed that ex vivo-generated murine megakaryocytes infused into mice release platelets within the pulmonary vasculature. Here we now show that infused human megakaryocytes also release platelets within the lungs of recipient mice. In addition, we observed a population of platelet-like particles (PLPs) in the infusate, which include platelets released during ex vivo growth conditions. By comparing these 2 platelet populations to human donor platelets, we found marked differences: platelets derived from infused megakaryocytes closely resembled infused donor platelets in morphology, size, and function. On the other hand, the PLP was a mixture of nonplatelet cellular fragments and nonuniform-sized, preactivated platelets mostly lacking surface CD42b that were rapidly cleared by macrophages. These data raise a cautionary note for the clinical use of human platelets released under standard ex vivo conditions. In contrast, human platelets released by intrapulmonary-entrapped megakaryocytes appear more physiologic in nature and nearly comparable to donor platelets for clinical application.
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