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Conducting Maximal and Submaximal Endurance Exercise Testing to Measure Physiological and Biological Responses to Acute Exercise in Humans
Published on: October 17, 2018
Human endurance and the heart at altitude
1Department of Physiological Hygiene, School of Hygiene University of Toronto, Toronto, Canada.
The Journal of Sports Medicine and Physical Fitness
|August 7, 2013
Summary
Human endurance relies on efficient oxygen transport. At moderate altitudes, physiological adjustments help, but significant drops in maximum oxygen intake occur, impacting performance. Higher altitudes pose greater risks.
Area of Science:
- Physiology
- Altitude Medicine
- Sports Science
Background:
- Human endurance is limited by oxygen transport from atmosphere to tissues.
- Key physiological processes include breathing, lung diffusion, and blood transport.
- At sea level, blood transport (hemoglobin and cardiac output) is the main resistance to oxygen uptake.
Purpose of the Study:
- To examine the physiological impact of altitude on human oxygen transport and endurance.
- To identify critical altitude thresholds affecting oxygen intake and performance.
- To understand compensatory mechanisms at varying altitudes.
Main Methods:
- The study discusses physiological parameters like alveolar ventilation, oxygen dissociation, and hemoglobin levels.
- It analyzes the effects of acute and prolonged altitude exposure.
- Performance metrics, specifically maximum oxygen intake, are considered.
Main Results:
- At 7350 ft, unacclimatized individuals experience an 8-10% decrease in maximum oxygen intake, reducing endurance performance.
- Moderate altitudes allow some compensation through increased ventilation and heart rate.
- Higher altitudes (above 7350 ft) lead to significant drops in arterial oxygen saturation and maximum oxygen intake.
Conclusions:
- Altitude significantly impacts oxygen transport, with performance decrements becoming critical above 7350 ft.
- Physiological acclimatization involves ventilation, buffering, and increased hemoglobin levels.
- Above 10,000 ft, severe exertion carries the risk of pulmonary edema.
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