Sleep and wake patterns in aircrew on a 2-Day layover on westward long distance flights
Lowden A, Akerstedt TAviat Space Environ Med 1998; 69:596-602
Abstract
Background: As part of a research program of sleep/wake disturbances in connection with irregular work hours and time zone transitions, the study aimed to describe the spontaneous sleep/wake pattern in connection with a westward (Stockholm to Los Angeles) transmeridian flight (-9 h) and short layover (50 h). Hypothesis: To describe all sleep episodes and the recovery process across 4 d, and to relate adjustment to individual differences. Methods: We monitored 42 SAS aircrew for 9 d with activity monitors and diary before, during and after flight. Results: During the outbound day the wake span was 21.7 h and 90% of the aircrew adopted local bed times on layover. The re- adaptation to normal sleep/wake patterns was rapid on the return. Napping was common (93%), especially on-board and before the return. Sleep efficiency dropped below 90% during layover, being felt to be too short and disturbed by awakenings, and gradually returned to normal across four recovery days. Recovery sleep was characterized by difficulties waking up and feelings of not being refreshed from sleep. Sleepiness symptoms increased during layover and gradually decreased across recovery days, still being elevated on day 4. Conclusions: In the present study we found that westward flights are associated with extended wake spans during layover, increased sleepiness, and slow recovery on return home. Strategic sleeping may counteract the effect somewhat, but individual differences are few.
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Table of Contents for Volume 69, Number 6 of the ASEM journal.