Using daytime sleep strategies to increase sleep duration during a week of simulated night work

One of the challenges for individuals who work at night is obtaining sufficient sleep during the day. Individuals adopt different sleep strategies in the breaks between night shifts, however these strategies have not been systematically compared. The aim of this study was to determine which of the four most common daytime sleep strategies produces the greatest amount and/or quality of sleep. In a between- groups design, 43 participants completed one of four strategies during a week of simulated night work in the laboratory. The only difference between strategies was in the timing of the 7- hr sleep opportunities that occurred during the 6 breaks between the 8- hr night shifts: a 7- hr sleep in the morning after work (08:30–15:30 hr), a 7- hr sleep in the evening before work (14:30–21:30 hr), a 5- hr sleep in the morning followed by a 2- hr sleep in the evening (split #1: 08:30 - 13:30 hr and 19:30–21:30 hr), or a 2- hr sleep in the morning followed by a 5- hr sleep in the evening (split #2: 08:30–10:30 hr and 16:30–21:30 hr). Sleep was monitored using polysomnography. For each participant, total sleep time and the amount of slow wave sleep and REM sleep were averaged over the 6 daytime sleep episodes and separate one- way ANOVAs were conducted for each variable. Total sleep time was significantly higher in the morning (390.6 ± 9.2 min) and evening strategies (389.6 ± 17.8 min) compared to the split #1 (358.0 ± 28.4 min) and split #2 (361.6 ± 37.7 min) strategies. There was no difference in the amount of slow wave sleep or REM sleep between strategies. More sleep was obtained in the morning and evening strategies com-pared to the split strategies. Interestingly, the four daytime sleep strategies were equally effective in terms of the amount of REM and slow wave sleep they provided. In future, it will be important to determine whether differences in sleep duration between strategies result in better performance and/or higher subjective alertness during night shifts.