The effect of high-altitude on human skeletal muscle energetics: P-MRS results from the Caudwell Xtreme Everest expedition.
Edwards LM,
Murray AJ,
Tyler DJ,
Kemp GJ,
Holloway CJ,
Robbins PA,
Neubauer S,
Levett D,
Montgomery HE,
Grocott MP,
Clarke K;
Caudwell Xtreme Everest Research Group.
Ahuja V, Aref-Adib G, Burnham R, Chisholm A, Clarke K, Coates D, Coates M, Cook D, Cox M, Dhillon S, Dougall C, Doyle P, Duncan P, Edsell M, Edwards L, Evans L, Gardiner P, Grocott M, Gunning P, Hart N, Harrington J, Harvey J, Holloway C, Howard D, Hurlbut D, Imray C, Ince C, Jonas M, van der Kaaij J, Khosravi M, Kolfschoten N, Levett D, Luery H, Luks A, Martin D, McMorrow R, Meale P, Mitchell K, Montgomery H, Morgan G, Morgan J, Murray A, Mythen M, Newman S, O'Dwyer M, Pate J, Plant T, Pun M, Richards P, Richardson A, Rodway G, Simpson J, Stroud C, Stroud M, Stygal J, Symons B, Szawarski P, Van Tulleken A, Van Tulleken C, Vercueil A, Wandrag L, Wilson M, Windsor J, Basnyat B, Clarke C, Hornbein T, Milledge J, West J.
Source
Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, Oxfordshire, United Kingdom. L.M.Edwards@utas.edu.au
Abstract
Many disease states are associated with regional or systemic hypoxia. The study of healthy individuals exposed to high-altitude hypoxia offers a way to explore hypoxic adaptation without the confounding effects of disease and therapeutic interventions. Using (31)P magnetic resonance spectroscopy and imaging, we investigated skeletal muscle energetics and morphology after exposure to hypobaric hypoxia in seven altitude-naïve subjects (trekkers) and seven experienced climbers. The trekkers ascended to 5300 m while the climbers ascended above 7950 m. Before the study, climbers had better mitochondrial function (evidenced by shorter phosphocreatine recovery halftime) than trekkers: 16+/-1 vs. 22+/-2 s (mean +/- SE, p<0.01). Climbers had higher resting [Pi] than trekkers before the expedition and resting [Pi] was raised across both groups on their return (PRE: 2.6+/-0.2 vs. POST: 3.0+/-0.2 mM, p<0.05). There was significant muscle atrophy post-CXE (PRE: 4.7+/-0.2 vs. POST: 4.5+/-0.2 cm(2), p<0.05), yet exercising metabolites were unchanged. These results suggest that, in response to high altitude hypoxia, skeletal muscle function is maintained in humans, despite significant atrophy.
- PMID:
- 20502713
- [PubMed - indexed for MEDLINE]
- PMCID: PMC2873292
Free PMC ArticleFigure 1Muscle phosphocreatine kinetics in recovery from moderate exercise: differences between experienced climbers and altitude-naïve subjects.
Data shown are means ± S.E.M.
PLoS One. PLoS One;5(5):e10681.
Figure 3The effect of altitude exposure on resting high-energy phosphates in skeletal muscle.
* different from pre-CXE at p<0.05; ** different from pre-CXE at p<0.01. CXE = Caudwell Xtreme Everest.
PLoS One. PLoS One;5(5):e10681.
Figure 2Individual changes in muscle cross-sectional area after a trip to high-altitude.
Dashed lines are climbers, solid lines are altitude-naïve subjects. Change in mean values is significant at p<0.05, n = 12.
PLoS One. PLoS One;5(5):e10681.
Figure 4The effect of altitude exposure on phosphocreatine ‘overshoot’ in skeletal muscle.
Values are means over the last minute of each period. CXE = Caudwell Xtreme Everest expedition, EXx = exercise bout x, RECx = recovery period after exercise bout x. ** different from pre-CXE at p<0.01; §End-REC1 PCr is different from resting PCr pre-CXE at p<0.05; ¶End-REC2 PCr is different from resting PCr post-CXE at p<0.05.
PLoS One. PLoS One;5(5):e10681.
Publication Types
MeSH Terms
Substances
Grant Support
Full Text Sources
Other Literature Sources
Medical