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Exercise training in chronic hypoxia has no effect on ventilatory muscle function in humans
R G Thomas1, P C LaStayo, H Hoppeler
1Department of Biological Sciences, Northern Arizona University, Flagstaff 86011-5640, USA.
Respiration Physiology
|August 26, 1998
Summary
Endurance training at high altitude did not improve ventilatory muscle function. Despite increased maximal oxygen uptake, breathing mechanics remained unchanged, suggesting training does not adapt these muscles in hypoxia.
Area of Science:
- Physiology
- Exercise Science
- Altitude Training
Background:
- Aerobic work capacity at high altitudes is limited by oxygen availability.
- Endurance training is hypothesized to stimulate ventilatory muscle adaptation through increased breathing.
- Investigating ventilatory muscle response to training in hypoxic conditions is crucial.
Purpose of the Study:
- To determine if 6 weeks of incremental endurance training in hypoxia induces functional adaptations in ventilatory muscles.
- To assess changes in ventilatory muscle pressure-flow characteristics and maximum sustainable ventilation capacity.
- To evaluate the impact of altitude training on human respiratory muscle function.
Main Methods:
- Ten permanent residents of La Paz, Bolivia (3600 m) underwent 6 weeks of incremental endurance training.
- Peak inspiratory muscle pressure-flow characteristics and maximum sustainable ventilation capacity were measured before and after training.
- Eight local residents served as controls for capacity testing.
Main Results:
- Maximal oxygen uptake (V(O2)max) in hypoxia increased by 19% after training.
- No significant changes were observed in maximum inspiratory pressure-flow slopes, maximum inspiratory pressure, peak inspiratory flow, or maximum volitional ventilation.
- Maximal sustainable minute ventilation did not differ between post-training and control subjects.
Conclusions:
- Endurance training, even when performed in hypoxic conditions, does not appear to induce significant functional adaptations in human ventilatory muscles.
- The observed increase in V(O2)max is not accompanied by improvements in respiratory muscle strength or endurance.
- These findings challenge the notion that hyperpnea from endurance training serves as a strong stimulus for ventilatory muscle adaptation at altitude.