Body temperature, shivering, blood pressure and heart rate during a standard cold stress in Australia and Antarctica.

1. Four men of European descent were exposed naked to an air temperature of 10 degrees C for 2 hr in Australia, and again after 24 weeks' residence at Mawson, Antarctica.2. Their ability to maintain rectal temperature during the test cold exposure significantly improved at Mawson. Shivering and cold diuresis did not change. The response of skin temperature did not change significantly except for a small increase in toe temperature. Bradycardia caused by the cold exposure was significantly greater at Mawson, but the rise in blood pressure did not change. Spontaneous fluctuations in rectal temperature that occurred during the cold exposure were intensified at Mawson.3. The results confirm those of a previous study at Mawson, and are attributed to general acclimatization to cold. It is suggested that tissue insulation increased as a result of enhanced vasoconstriction.