Sleep and circadian rhythms of an airline pilot operating on the polar route: a case study

This study was planned and performed as a first step to assess sleep behaviour and circadian rhythmicity in aircrews operating on regular passenger flights between Germany and Japan via Anchorage, AK. Sleep patterns as well as continuous recordings of ECG and temperature were obtained from a B747 captain during a period of 13 d, including a preceding control day, 8 d on duty and 4 d at home base after return. Sleep behaviour and circadian rhythms changed dramatically due to adverse effects from the duty roster on the polar route. Sleep periods became fragmented into several sleep periods per day in a very irregular manner. Total sleep duration was shortened and sleep deficits occurred between flights. After return to the home base, sleep distribution remained divided into two intervals per day. The circadian system was considerably disrupted on route. Effects associated with irregular duty and sleep patterns intensified desynchronization. Readjustment was extremely slow resulting in a phase-displacement of at least 10 h even after being home for 4 d. Altogether, the results give reason for serious concerns and for the conclusion to strongly recommend more extensive studies on this route.