A Study of Mood Changes and Personality during a 31-Day Period of Chronic Hypoxia in a Hypobaric Chamber (Everest-Comex 97)

High altitudes of more than 3,000 meters produce physiological disorders and adverse changes in mood states. In the present study, we report analyses of mood states and personality traits in eight experienced climbers participating in a 31-day period of confinement in hypobaric chamber and gradual decompression from sea level to 8,848 m (Experiment ‘Everest-Comex 97’). The subjects were tested at 5,500 m and 6,500 m on Day 13, 5,000 m and 6,500 m on Day 24, and 8,000 m and 8,848 m altitude on Days 27 and 31. Adverse changes in mood states, such as Vigor and Fatigue, occurred at 8,000 m and 8,848 m, which were significantly correlated with cerebral altitude symptomatology. In addition, a significant negative correlation was found between Fatigue and Factor C, which is a personality measure of emotional stability. We suggest that individuals with low emotional stability could be more sensitive to environmental stressors than more emotionally stable subjects who face reality.