Overnight duty impairs behaviour, awake activity and sleep in medical doctors.

BACKGROUND: The impact of prolonged work cycles among senior doctors remains disputed. We evaluated the effects of overnight duty on awake activity and sleep quality in senior doctors in emergency medical specialties. METHODS: Thirty-six healthy doctors were monitored during a 2-week period including three separate 84 h on-call cycles. An on-call cycle consisted of the night and the day before night duty; the night duty itself and the subsequent 2 days and nights after night duty. The first day after night duty could either be worked or not. Actigraphy was used to measure physical activity and to evaluate sleep duration and quality. A standardized questionnaire was used to assess daytime performance and night sleep quality. RESULTS: Night actigraphy demonstrated that on-call work induced a significant reduction in sleep duration that was not recovered during the subsequent two nights. Sleep during the night duty itself was fragmented and of poor quality. Awake activity was significantly impaired on the day after night duty. Although subjectively night sleep quality did not differ between the nights before and after night duty, all subjective daytime parameters were impaired the day after night duty, and mood, fatigue and concentration remained altered on the second day. Working the day after night duty impaired objective measurements of daytime activity and sleep quality during the subsequent two nights. CONCLUSIONS: On-call night work in acute specialties induces sleep debt associated with prolonged impairment of awake activity, sleep quality and performance. Not working the following day after an on-call night allows partial recovery of sleep quality to begin.