Urinary excretion of adrenal steroids, catecholamines and electrolytes in man, before and after acclimatization to cold in Antarctica.

1. Urine samples were collected from four men before and during test cold exposures in Melbourne, Australia, and Mawson, Antarctica. Changes in the response of body temperature to the test exposures showed that the men had acclimatized to cold at Mawson.2. Excretion rates of 17-hydroxycorticosteroids and 17-ketosteroids were significantly greater at Mawson than in Melbourne, in both the pre-exposure and exposure periods.3. Excretion rates of noradrenaline, adrenaline, sodium, potassium and creatinine did not differ significantly between Mawson and Melbourne, nor did urine flow rates.4. During the cold exposure significant increases occurred, to the same extent at Mawson as in Melbourne, in urine flow rate and in all measured urinary constituents except creatinine.

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.

Cardiovascular and metabolic responses to noradrenaline in man, before and after acclimatization to cold in Antarctica.

1. Four men of European descent were infused with noradrenaline at rates of 0.038, 0.075, 0.150 and 0.300 mug/kg.min in Australia, and again after 29 weeks' residence at Mawson, Antarctica. A concurrent study of their responses to whole-body cooling showed that they acclimatized to cold in Antarctica.2. Blood pressure rose and heart rate fell in proportion to the dose of noradrenaline infused. The response was much less after than before acclimatization in three of the four subjects. Subjective effects of the drug decreased in proportion to the decrease in the pressor effect.3. Finger temperature fell in proportion to the dose infused, in three subjects. The response was unchanged or increased after acclimatization.4. Oxygen consumption was initially unaffected by noradrenaline, but after acclimatization it apparently increased in proportion to the dose infused. The increase in pulmonary ventilation during infusion was slightly greater after acclimatization.