Energy balance and cold stress in polar travellers
A study has been undertaken to determine the energy balance and thermal stress of skidoo drivers in Antarctica, and to compare them in those respects with dog sledgers. A background study of the variation over a year in various physiological parameters in some of the travellers studied was also carried out. 1. Resting metabolic rate. blood pressure, and pulse rate, body weight and skin fold thickness were measured monthly over a period of one year in six men living on a scientific base in Antarctica. Percentage body fat was determined from body weight and skin fold thickness. Skin fold thickness and percentage body fat were greater than that to be expected in the U.K.: other parameters did not differ significantly from accepted norms. Most of the parameters measured showed similar patterns cf variation: high values in spring or summer, falling in winter, with a small-peak after midwinter, rising again in autumn. There was a significant reduction in skin fold thickness and body fat over the year, but no significant change in other parameters. 2. Energy intake, expenditure and balance, weight loss and fat loss were determined in men travelling overland in Antarctica. Thirteen trips, seven by skidoo and six by dog sledge, each of approximately eleven days, were studied. Energy deficit was found on all trips. Energy intake, expenditure, and deficit were significantly greater on dog trips. Weight loss and fat loss were also greater, but the differences were not statistically significant. 3. Skin temperature was measured and thermal comfort, shivering, sweating, clothing and activity were recorded on ten day trips, six by dog sledge, and four by skidoo. Skin temperatures on dog runs were lower and more variable than on skidoo runs, and differences between central and peripheral temperatures greater. Thermal discomfort, shivering and sweating were more common on dog runs.