Body temperature and basal metabolic changes during acclimatization to altitude (3,500 m) in man.

Oral temperature (Tor), mean weighted skin temperature (Ts), mean body temperature (Tb) and basal oxygen consumption were studied on twelve young men at sea level. Then they were flown to an altitude of 3,500 m and the readings were continued after 24 hours of their arrival and thereafter at four day intervals for a period of 25 days. Thereafter the subjects were flown back and retested at sea level. Oxygen consumption was recorded at weekly intervals only. The changes in body temperature were compared with those of their basal oxygen consumption. The results indicate that there is a slight rise in the Tor on arrival at altitude and thereafter a gradual fall. A steady and continuous fall was recorded in Ts and Tb throughout the stay at altitude. The basal oxygen consumption showed an initial rise which has come back to normal by the third week of their stay at altitude. On retest, the valves of body temperature and oxygen consumption reached their own initial sea-level pattern. The observation suggests that central mechanisms are involved in bringing about a fall in body temperature during altitude acclimatization.