In the past, trainees worked up to 140 hours a week, but more recently, the accreditation council for Graduate Medical Education limited hours for medical residents in the United States to less than 320 hours in a 4-week period (except for some programs that are exempt, which are allowed up to 32 additional hours). This study tested the proposal that eliminating extended work shifts for interns will significantly increase their hours of sleep and reduce attentional failures. Twenty interns were evaluated during 2 3-week rotations in intensive care units, once during a traditional schedule that included extended work shifts and once during a schedule limiting work hours to 16 consecutive hours. The traditional schedule allowed work periods of 30 consecutive hours every other shift. Participants kept sleep logs and underwent weekly periods of 72 to 96 hours of continuous polysomnography.
Interns worked a mean of 85 hours weekly on the traditional schedule and 65 hours per week on the interventional schedule. All but 3 of the 20 interns worked more than 80 hours per week on the traditional schedule, whereas all worked less than this with the intervention. The difference in work hours averaged 19.5 per week or 69 hours per rotation. On the traditional schedule, 60% of shifts lasted more than 24 hours; 84% of work hours were during these shifts. Interns on the intervention schedule slept nearly 6 fewer hours per week than with the intervention; all but 3 of them slept more during the altered schedule. There was a predicted loss of 19 minutes of sleep per week for each additional hour of work. The interns averaged 1.8 hours of sleep between 9 pm and 8 am when on the traditional schedule, significantly longer than when working the corresponding hours during the intervention schedule. Attentional failures occurring between 11 pm and 7 am were more than twice as frequent during the traditional schedule compared with the intervention schedule and 1.5 times the rate from 7 am to 10 pm.
Eliminating extended work shifts significantly increased the duration of sleep in this study and reduced the frequency of attentional failures during nighttime work shifts.