Medical interns on a float schedule with consecutive 12-hour night shifts showed better sleep quality, more regular sleep patterns, stable mood, and cognitive performance compared to those on a 24-hour call schedule, according to a recent study.
Researchers investigated the effects of a 24-hour call schedule versus a night float schedule on sleep, well-being, and cognitive performance among medical interns. Conducted over 8 weeks in a Singapore teaching hospital, the study included 96 participants who were monitored using wearable sleep trackers and smartphone-based assessments.
Results, published in JAMA Network Open, showed interns on a night float schedule, which involved consecutive 12-hour night shifts, had more regular sleep patterns and better sleep quality than those on the 24-hour call schedule. The call schedule was associated with poorer mood, lower motivation, increased sleepiness, and impaired cognitive function, particularly in vigilance and working memory. In contrast, these outcomes were not observed in interns on the float schedule.
Specifically, the call schedule was linked to a 13% decline in mood, whereas no significant mood changes were observed in the float schedule group. Additionally, the call schedule was associated with a 29% rise in sleepiness, while the float schedule did not result in a statistically significant change in sleepiness.
Sleep regularity, as measured by the Sleep Regularity Index, was significantly higher in the float group (mean score 69.4) compared with the call group (mean score 56.1). Sleep quality, assessed via the Pittsburgh Sleep Quality Index, was also better among interns on the float schedule (mean score 5.4) compared with those on the call schedule (mean score 6.5). Both groups benefited from naps during night shifts, with improved vigilance performance observed following naps.
Michael W. L. Chee, MBBS, disclosed serving on the medical advisory board of Oura Ring, receiving personal consulting fees and grants from Oura Ring for device evaluation outside of this study. No additional disclosures were noted.