DIFFERENCES IN SLEEP DURATION AND QUALITY BETWEEN WEEKDAYS AND WEEKENDS IN JAPANESE ADULTS

Chronic, lifestyle-driven sleep restriction is common in many modern 24-hour societies. In these instances, people will compensate for their weekday sleep deprivation by sleeping more on weekends. Many cohort studies revealed that weekend sleep extension compensates for short weekday sleep in relation to mortality, obesity, and hypertension. However, these studies used self-reported sleep durations, and did not focus on objective sleep quality. The aim of this study is to evaluate differences in sleep duration and quality between weekdays and weekends using a portable EEG monitoring device. Twenty-onetwo Japanese volunteers, aged 20-67 years (4 female and 17 male), enrolled in this study. They underwent seven days of monitoring using a portable EEG device that recorded their sleep activity. These recordings were used to evaluate sleep parameters, such as total sleep time (TST), sleep efficiency [% of time in bed (TIB)], sleep latency, wake time (% TIB), wake after sleep onset (WASO), REM sleep, light sleep (stages N1 and N2), and deep sleep (stage N3). TIBs on Friday and Saturday night were significantly longer than other nights of the week, leading to longer TST on Friday and Saturday night. Sleep efficiency (% TIB) was better on weekdays than weekends, and wake time (% TIB) was greater on Friday, Saturday and Sunday nights as compared to other days of the week. WASO and light sleep were longer on weekend nights than weekday nights, meanwhile, REM sleep and deep sleep were unaffected by the day of the week. TIB and TST increased on weekend nights, but sleep efficiency tended to decrease. REM sleep and deep sleep were stable throughout the week, while light sleep increased as TST was longer. Extended TIB may increase WASO and light sleep. Collaboration study with The KAITEKI Institute, Inc.