Gokyo Khumbu/Ama Dablam Trek 2012: effects of physical training and high-altitude exposure on oxidative metabolism, muscle composition, and metabolic cost of walking in women.
Eur J Appl Physiol
; 116(1): 129-44, 2016 Jan.
Article
em En
| MEDLINE
| ID: mdl-26349745
ABSTRACT
PURPOSE:
We investigated the effects of moderate-intensity training at low and high altitude on VO2 and QaO2 kinetics and on myosin heavy-chain expression (MyHC) in seven women (36.3 yy ± 7.1; 65.8 kg ± 11.7; 165 cm ± 8) who participated in two 12- to 14-day trekking expeditions at low (598 m) and high altitude (4132 m) separated by 4 months of recovery.METHODS:
Breath-by-breath VO2 and beat-by-beat QaO2 at the onset of moderate-intensity cycling exercise and energy cost of walking (Cw) were assessed before and after trekking. MyHC expression of vastus lateralis was evaluated before and after low-altitude and after high-altitude trekking; muscle fiber high-resolution respirography was performed at the beginning of the study and after high-altitude trekking.RESULTS:
Mean response time of VO2 kinetics was faster (P = 0.002 and P = 0.001) and oxygen deficit was smaller (P = 0.001 and P = 0.0004) after low- and high-altitude trekking, whereas Ë QaO2 kinetics and Cw did not change. Percentages of slow and fast isoforms of MyHC and mitochondrial mass were not affected by low- and high-altitude training. After training altitude, muscle fiber ADP-stimulated mitochondrial respiration was decreased as compared with the control condition (P = 0.016), whereas leak respiration was increased (P = 0.031), leading to a significant increase in the respiratory control ratio (P = 0.016).CONCLUSIONS:
Although training did not significantly modify muscle phenotype, it induced beneficial adaptations of the oxygen transport-utilization systems witnessed by faster VO2 kinetics at exercise onset.Palavras-chave
Texto completo:
1
Temas:
ECOS
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Financiamentos_gastos
Bases de dados:
MEDLINE
Assunto principal:
Consumo de Oxigênio
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Resistência Física
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Caminhada
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Músculo Esquelético
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Altitude
Tipo de estudo:
Health_economic_evaluation
Limite:
Adult
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Female
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Humans
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Middle aged
Idioma:
En
Revista:
Eur J Appl Physiol
Assunto da revista:
FISIOLOGIA
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
Itália