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Salvadego D, Grassi B, Keramidas ME, Eiken O, McDonnell AC, Mekjavic IB. Heterogeneity of human adaptations to bed rest and hypoxia: a retrospective analysis within the skeletal muscle oxidative function. Am J Physiol Regul Integr Comp Physiol 2021; 321:R813-R822. [PMID: 34585615 DOI: 10.1152/ajpregu.00053.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This retrospective study was designed to analyze the interindividual variability in the responses of different variables characterizing the skeletal muscle oxidative function to normoxic (N-BR) and hypoxic (H-BR) bed rests and to a hypoxic ambulatory confinement (H-AMB) of 10 and 21 days. We also assessed whether and how the addition of hypoxia to bed rest might influence the heterogeneity of the responses. In vivo measurements of O2 uptake and muscle fractional O2 extraction were carried out during an incremental one-leg knee-extension exercise. Mitochondrial respiration was assessed in permeabilized muscle fibers. A total of 17 subjects were included in this analysis. This analysis revealed a similar variability among subjects in the alterations induced by N-BR and H-BR both in peak O2 uptake (SD: 4.1% and 3.3% after 10 days; 4.5% and 8.1% after 21 days, respectively) and peak muscle fractional O2 extraction (SD: 5.9% and 7.3% after 10 days; 6.5% and 7.3% after 21 days), independently from the duration of the exposure. The individual changes measured in these variables were significantly related (r = 0.66, P = 0.004 after N-BR; r = 0.61, P = 0.009 after H-BR). Mitochondrial respiration showed a large variability of response after both N-BR (SD: 25.0% and 15.7% after 10 and 21 days) and H-BR (SD: 13.0% and 19.8% after 10 and 21 days); no correlation was found between N-BR and H-BR changes. When added to bed rest, hypoxia altered the individual adaptations within the mitochondria but not those intrinsic to the muscle oxidative function in vivo, both after the short- and medium-term exposures.
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Affiliation(s)
- Desy Salvadego
- Department of Automation, Biocybernetics and Robotics, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Bruno Grassi
- Department of Medicine, University of Udine, Udine, Italy
| | - Michail E Keramidas
- Department of Environmental Physiology, Swedish Aerospace Physiology Centre, Royal Institute of Technology, Stockholm, Sweden
| | - Ola Eiken
- Department of Environmental Physiology, Swedish Aerospace Physiology Centre, Royal Institute of Technology, Stockholm, Sweden
| | - Adam C McDonnell
- Department of Automation, Biocybernetics and Robotics, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Igor B Mekjavic
- Department of Automation, Biocybernetics and Robotics, Jožef Stefan Institute, Ljubljana, Slovenia.,Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
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Doria C, Verratti V, Pietrangelo T, Fanò-Illic G, Bisconti AV, Shokohyar S, Rampichini S, Limonta E, Coratella G, Longo S, Cè E, Esposito F. Changes in energy system contributions to the Wingate anaerobic test in climbers after a high altitude expedition. Eur J Appl Physiol 2020; 120:1629-1636. [PMID: 32494861 DOI: 10.1007/s00421-020-04392-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 05/12/2020] [Indexed: 12/12/2022]
Abstract
PURPOSE The Wingate anaerobic test measures the maximum anaerobic capacity of the lower limbs. The energy sources of Wingate test are dominated by anaerobic metabolism (~ 80%). Chronic high altitude exposure induces adaptations on skeletal muscle function and metabolism. Therefore, the study aim was to investigate possible changes in the energy system contribution to Wingate test before and after a high-altitude sojourn. METHODS Seven male climbers performed a Wingate test before and after a 43-day expedition in the Himalaya (23 days above 5.000 m). Mechanical parameters included: peak power (PP), average power (AP), minimum power (MP) and fatigue index (FI). The metabolic equivalents were calculated as aerobic contribution from O2 uptake during the 30-s exercise phase (WVO2), lactic and alactic anaerobic energy sources were determined from net lactate production (WLa) and the fast component of the kinetics of post-exercise oxygen uptake (WPCr), respectively. The total metabolic work (WTOT) was calculated as the sum of the three energy sources. RESULTS PP and AP decreased from 7.3 ± 1.1 to 6.7 ± 1.1 W/kg and from 5.9 ± 0.7 to 5.4 ± 0.8 W/kg, respectively, while FI was unchanged. WTOT declined from 103.9 ± 28.7 to 83.8 ± 17.8 kJ. Relative aerobic contribution remained unchanged (19.9 ± 4.8% vs 18.3 ± 2.3%), while anaerobic lactic and alactic contributions decreased from 48.3 ± 11.7 to 43.1 ± 8.9% and increased from 31.8 ± 14.5 to 38.6 ± 7.4%, respectively. CONCLUSION Chronic high altitude exposure induced a reduction in both mechanical and metabolic parameters of Wingate test. The anaerobic alactic relative contribution increased while the anaerobic lactic decreased, leaving unaffected the overall relative anaerobic contribution to Wingate test.
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Affiliation(s)
- Christian Doria
- Department of Biomedical Sciences for Health, Università Degli Studi Di Milano, Via G. Colombo 71, 20133, Milan, Italy.
| | - V Verratti
- Department of Psychological Sciences, Health and Territory, University "G. D'Annunzio" of Chieti-Pescara, Chieti, Italy
| | - T Pietrangelo
- Department of Neuroscience, Imaging and Clinical Sciences, University "G. D'Annunzio" of Chieti-Pescara, Chieti, Italy
| | - G Fanò-Illic
- Department of Neuroscience, Imaging and Clinical Sciences, University "G. D'Annunzio" of Chieti-Pescara, Chieti, Italy
| | - A V Bisconti
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - S Shokohyar
- Department of Biomedical Sciences for Health, Università Degli Studi Di Milano, Via G. Colombo 71, 20133, Milan, Italy
| | - S Rampichini
- Department of Biomedical Sciences for Health, Università Degli Studi Di Milano, Via G. Colombo 71, 20133, Milan, Italy
| | - E Limonta
- Department of Biomedical Sciences for Health, Università Degli Studi Di Milano, Via G. Colombo 71, 20133, Milan, Italy.,IRCCS, Istituto Ortopedico Galeazzi, Milan, Italy
| | - G Coratella
- Department of Biomedical Sciences for Health, Università Degli Studi Di Milano, Via G. Colombo 71, 20133, Milan, Italy
| | - S Longo
- Department of Biomedical Sciences for Health, Università Degli Studi Di Milano, Via G. Colombo 71, 20133, Milan, Italy
| | - E Cè
- Department of Biomedical Sciences for Health, Università Degli Studi Di Milano, Via G. Colombo 71, 20133, Milan, Italy.,IRCCS, Istituto Ortopedico Galeazzi, Milan, Italy
| | - F Esposito
- Department of Biomedical Sciences for Health, Università Degli Studi Di Milano, Via G. Colombo 71, 20133, Milan, Italy.,IRCCS, Istituto Ortopedico Galeazzi, Milan, Italy
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