Physiologic adaptation changes of the "Bering Bridge" expedition participants.
Cardiorespiratory measurements were repeatedly performed on indigenous and Caucasian Soviet and American male team members of the Bering Bridge expedition which covered approximately 1280 km over a 61 day period. Significant baseline differences in cardiorespiratory functions at rest and during submaximal cycle ergometer exercise were noted between racial groups. Indigenous members had significantly lower mean vital lung capacity and oxygen consumption levels during submaximal exercise, but a greater systolic blood pressure response to exercise. The energy cost during submaximal work decreased during the trek in both groups, but was marked in the Caucasians, suggesting that the indigenous subjects were better adapted at baseline to the Arctic environment. Overall, there was stabilization of functional responses in four of seven parameters studied, although differences between racial groups remained the same.