Elevation-dependent symptom, mood, and performance changes produced by exposure to hypobaric hypoxia.

Area of Science:

• Environmental Physiology
• Human Physiology
• Altitude Medicine

Background:

• High altitude exposure (above 3,000 m) is known to affect unacclimatized individuals.
• Changes in symptoms, mood, and cognitive/motor performance are expected with increasing elevation and duration.

Purpose of the Study:

• To investigate the effects of varying altitude levels and exposure durations on physiological and psychological parameters.
• To determine the dose-response relationship between hypobaric hypoxia and human performance.

Main Methods:

• Twenty-three males were exposed to simulated altitudes of 500 m, 4,200 m, and 4,700 m in an altitude chamber.
• Standardized tests measuring symptoms, mood, and cognitive/motor performance were administered multiple times during 4.5-hour exposures.
• Hypobaric hypoxia was the primary environmental stressor.

Main Results:

• Altitude exposure significantly altered symptoms, mood, and performance in an elevation-dependent manner.
• Adverse effects were more pronounced at higher altitudes (4,700 m vs. 4,200 m) and generally increased with longer exposure durations.
• All measured parameters were affected at 4,700 m, while only some were affected at 4,200 m.

Conclusions:

• Even short exposures to hypobaric hypoxia can degrade specific aspects of human symptoms, mood, and performance.
• The severity of these adverse effects escalates significantly when testing occurs at 4,700 m compared to 4,200 m.
• Graded effects on these parameters are evident with increasing altitude and duration of exposure.