Effects of workload on residents' sleep duration: objective documentation.

Sleep-wake cycles of 27 residents from the 800-bed Rambam hospital, which serves the northern part of Israel, were investigated by wrist-worn actigraphs. Fifteen subjects (aged 30.6 +/- 4.6) worked in wards with a "heavy" workload, and 12 (aged 35 +/- 2.6) in wards with a "light" load. There were significant differences among the residents in sleep duration. Residents working in the emergency room had the shortest sleep periods, and those working in "light" wards had the longest. There was no significant increase in sleep duration the day after the night "on call." Sleep duration was significantly negatively correlated with the number of new admissions, and with the subjective daily assessment of work load. It is concluded that residents working in wards with a heavy load suffer from chronic partial sleep deprivation, which should be taken into consideration in residents' work regulation.