A recent retrospective review of the effect of extended periods of daylight and darkness on those living at the British Antarctic Survey operated Halley Research Station prior to 2003 has been published. Living for extended periods in Antarctica exposes base personnel to extremes of daylength (photoperiod) and temperature. Photoperiod is the major time cue governing the timing of seasonal events such as reproduction in many species and when overwintering a strong seasonal and circadian(24hr) time cue is absent. Sleep, alertness and waking performance are critically dependent on optimum circadian phase.
The results were based on a series of studies regarding human seasonal and circadian status, and the effects of light treatment, in the small overwintering, isolated community, living in the same conditions for many months at Halley, prior to 2003. Little evidence was found of Seasonal Affective Disorder (SAD), or change in duration of melatonin production with season, however the timing of the melatonin rhythm itself was altered. The findings provide groundwork for dealing with the impact of the changes to photoperiod.
Josephine Arendt, Benita Middleton, Human seasonal and circadian studies in Antarctica (Halley, 75°S), General and Comparative Endocrinology, 2017.