Peripheral vascular response to local cold stress of tropical men during sojourn in the Arctic cold region.

Peripheral vascular response to local cold stress was studied on 4 groups of volunteers by eliciting cold-induced vasodilatation (CIVD) response during immersion of right hand in cold water (4 degrees C) for 30 min, to examine whether tropical men can get acclimatized to local cold compared to temperate zone people, during Arctic cold exposure. Group A and B (10 each) were drawn from tropical region of India, while Group C and D (6 each) from temperate zone of Russia and natives of Arctic, respectively. Initial study was conducted on control Group A at Delhi. Group B was airlifted to the Arctic (70 degrees N, 38 degrees E), where measurements were done on them during the seventh week of acclimatization, then they were flown back to Delhi and retested. For comparison, study was done at the Arctic on six migrants (Group C) from temperate zone of Russia and 6 natives (Group D) of the Arctic. There was a significant improvement of CIVD response and peripheral blood flow of tropical men due to acclimatization to Arctic environment, which was similar to that of the migrants but lower than the natives. Thus local cold acclimatization is possible even in tropical men as in those of the temperate zone people.