Sleep and Time Zone Changes

No definite evidence of circadian effects due to alteration in time zone were demonstrated, but early morning waking was a feature of the first five nights in the new time zone, particularly in the older subjects.

Abstract

Alterations occurred in the overnight sleep patterns of four healthy male subjects before and after trans-Atlantic flights in both directions. On the first night after a London/San Francisco flight, stage 4 sleep was enhanced, and rapid eye movement (REM) sleep was depressed, although the distribution of both types of sleep during the night was not altered. Early morning waking was a feature of the first five nights in the new time zone, particularly in the older subjects. Similar changes occurred after the return flight. There was no evidence of enhancement of REM sleep and the alteration in the distribution of REM sleep which has been noted in laboratory studies of sleep reversal. However, the changes found were in accord with travellers' complaints. No definite evidence of circadian effects due to alteration in time zone were demonstrated.