The Impact of Lunch Timing on Nap Quality
Sleep , Chrononutrition , Napping , Circadian Rhythms
The human sleep-wake cycle follows a regular circadian rhythm, which is controlled by an internal biological clock (the suprachiasmatic nucleus), as well as external cues that aid in maintaining the system’s precise rhythmicity. Previous research on one of these external cues, meal timing, has yielded inconclusive results as to whether eating shortly before sleep onset negatively impacts sleep quality. To date, few studies have examined the effect of meal timing on the quality of daytime naps. Here, we used polysomnographic methods (EEG, EOG, EMG) and subjective self-reports of sleep quality and fatigue to examine whether the timing of lunch (1 vs. 2 hour interval between lunch and napping) impacts nap quality. Results revealed that subjective ratings and objective polysomnographic measures (total sleep time, sleep efficiency, sleep onset latency) of sleep quality were higher in the 2-hour condition relative to the 1-hour interval. Together, these findings suggest that a longer time interval between food intake and a subsequent nap can improve sleep quality, leading to more restorative sleep. Future research should continue to identify conditions that improve nap quality, thus maximizing the well-documented beneficial effects of sleep on human health and cognitive functioning.