Human sleep patterns in Antarctica

Eight volunteers wintering in a French coastal station in Antarctica underwent 156 polysomnographic night recordings. The subjects, selected for their usual good sleeping habits, were recorded on 17-21 nights throughout the wintering in sessions of 2 to 3 consecutive nights. A two-way analysis of variance showed that most of the subjects' sleep characteristics were not similar, leading the authors to study the individual time course of sleep variables. As the subjects slept in their own comfortable quarters, there was no "polar insomnia," no first night effect, nor any relationship between sleep pattern variations and climatic changes. In all subjects, delta sleep tended to increase throughout the wintering, whereas stages 1 and 2 decreased. No significant variation was seen in paradoxical sleep (PS), neither between subjects nor with time. PS latency was also within normal range, but it was bimodally distributed in subjects S1, S2, and S8. Some other sleep variables also varied in certain subjects. Such was the case for sleeping time, which decreased throughout the wintering period in subject S8, the least adapted individual. However, due to the limited number of subjects, no statistical attempt could be made to link individual differences in sleep patterns and adaptation to life in Antarctica.