| Improved V'O2 uptake kinetics and shift in muscle fiber type in high altitude trekkers. | |
| | |
MedLine Citation:
|
PMID: 21868681 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
|
The study investigated the effect of prolonged hypoxia on central (i.e. cardiovascular O2 delivery, Q'aO2) and peripheral (i.e. O2 utilization) determinants of oxidative metabolism response during exercise in humans. To this aim, 7 male mountaineers were examined before and immediately after the Himalayan Expedition INTERAMNIA 8000 - MANASLU 2008 lasting 43 days, among which 23 above 5000 m. The subjects showed a decrease in body weight (p < 0.05) and of power output during a Wingate test (p < 0.05) and an increase of thigh cross sectional area (p < 0.05). Absolute maximal uptake (V'O2max) did not change. The mean response time (MRT) of V'O2 kinetics at the onset of step sub-maximal cycling exercise was significantly reduced from 53.8 s ± 10.9 to 39.8 s ± 10.9 (p < 0.05), whereas that of Q'aO2 was not. Analysis of single fibers dissected from vastus lateralis biopsies revealed that the expression of slow isoforms of both heavy and light myosin subunits increased, whereas that of fast isoforms decreased. Unloaded shortening velocity of fibers was significantly decreased. In summary, independent findings converge in indicating that adaptation to chronic hypoxia brings about a fast-to slow transition of muscle fibers resulting in a faster activation of the mitochondrial oxidative metabolism. These results indicate that a prolonged and active sojourn in hypoxia may induce muscular ultra structural and functional changes similar to those observed after aerobic training. |
| | |
Authors:
|
Christian Doria; Luana Toniolo; Vittore Verratti; Pasqua Cancellara; Tiziana Pietrangelo; Valeria Marconi; Antonio Paoli; Silvia Pogliaghi; Giorgio Fano; Carlo Reggiani; Carlo Capelli |
Publication Detail:
|
Type: JOURNAL ARTICLE Date: 2011-8-25 |
Journal Detail:
|
Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: - ISSN: 1522-1601 ISO Abbreviation: - Publication Date: 2011 Aug |
Date Detail:
|
Created Date: 2011-8-26 Completed Date: - Revised Date: - |
Medline Journal Info:
|
Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: - |
Other Details:
|
Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
|
1University of Chieti. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
|
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Low-volume high-intensity interval training reduces hyperglycemia and increases muscle mitochondrial...
Next Document: Pharmacological curve fitting to analyze cutaneous adrenergic responses.