Responses of Arctic and tropical men to a standard cold test and peripheral vascular responses to local cold stress in the Arctic.

Thermoregulatory, metabolic and peripheral vascular responses to cold were studied in two groups (six each) of healthy men during exposure to the natural cold environment of the Arctic. Group A comprised of two arctic natives and four temporary residents who had migrated from the temperature zone of Russia. Group B consisted of six soldiers from a tropical region (India). Group B was airlifted to the arctic (70 degrees N, 38 degrees E). Both groups stayed in a field camp. The experiments were conducted during the 7th week of the stay. The volunteers were subjected to a standard cold test at 10 degrees C for 2 h wearing only shorts. Their heart rate, blood pressure, ventilation, oxygen consumption, oral temperature, mean skin and extremity temperatures were recorded initially and at 30 min intervals during standard cold test. The cold-induced vasodilatation response in both groups was also studied separately. The tropical natives (Group B) were flown back to Delhi and retested after 6 weeks. The physiological responses to general cold exposure as well as peripheral vascular response to local arctic cold stress were similar in both groups. The observation suggested that cold acclimatization in tropical men is similar to that of the people of Russian origin from a temperature zone.