Effects of exercise at high altitudes on young adults.

Outward Bound programs are carried out throughout the world, and many of these courses occur at altitudes above 3000 m (10,000 ft). As more knowledge is accumulated about health problems at high altitudes, exercise has been implicated as a factor contributing to acute mountain sickness in susceptible individuals. Thus, exercise conditioning programs occurring at high altitudes have come under scrutiny. Twenty-eight young men and women were enrolled in an Outward Bound course at an altitude over 3000 m for a 21-day period. Twelve of the 28 individuals developed shortness of breath, cough, or both by the third day of the course. Of these 12, seven had pulmonary function abnormalities: three having evidence of large airway involvement and four having findings of small airway involvement. The symptoms were not significant enough to interfere with acclimatization and the muscular conditioning aspects of the program. Although at altitudes between 3000 m and 4300 m, pulmonary function abnormalities of acute mountain sickness develop in a significant number of participants, the abnormalities were not significant enough to prevent persons from completing the course or achieving marked improvements in fitness measurements.