The influence of seasonal variation, diet and physical activity on Ssrum lipids in young men in Antarctica

The long-term effects of diet, physical activity and seasonal variation on serum lipids have been studied over a period of one year (1961) in members of the British and South African Antarctic Surveys based at Halley Bay (75.30°S) and Sanae (70.30°S). The duration of the study spanned roughly three seasons: (1) February to April (summer) with daylight and outside temperatures ranging from –12 to –21°c., strenuous activity and average daily food intake of 3,850 calories; (2) April to September (winter) with polar night and outside temperatures ranging from –23 to –35°c., minimal activity and a food intake of 3,363 calories; and (3) September to January (summer) with daylight and outside temperatures ranging from –6 to –14°c., strenuous activity (including sledging journeys) and food intake of 3,663 calories. Seasonal changes in serum total cholesterol, phospholipid and triglyceride levels were minimal although physical activity and dietary intake showed considerable variation; the latter factors apparently balancing each other. The changes in the alpha- and beta-lipoprotein cholesterol concentration were significant. In winter beta-lipoprotein cholesterol levels rose significantly while alpha-lipoprotein cholesterol levels fell significantly. Similar significant changes were shown after sledging journeys; increased activity and energy expenditure resulting in decreased beta-lipoprotein cholesterol concentration with a corresponding increase in alpha-lipoprotein cholesterol concentration. One month after the sledging journeys, the levels had returned to those which existed before sledging. Studies with subjects spending their second year in the polar regions showed attenuation of all lipid parameters investigated.

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