The effects of napping on night‐time sleep in healthy young adults

Summary The discrepancies in the effects of napping on sleep quality may be due to differences in methodologies, napping behaviours, and daytime activity levels across studies. We determined whether napping behaviours and daytime activity levels are associated with night‐time sleep fragmentation and sleep quality in young adults. A total of 62 healthy adults (mean [SD] age 23.5 [4.2] years) completed screening questionnaires for sleep habits, physical activity, medical and psychological history. Actigraphy was used to record sleep including naps. The fragmentation algorithm (KRA) was applied to the actigraphic data to measure night‐time sleep fragmentation. We classified participants’ nap frequency as “non‐nappers” (0 naps/8 days), “moderate nappers” (1–2 naps/8 days) or “frequent nappers” (≥3 naps/8 days) naps. Nap duration was defined as “short” (≤60 min) or “long” (>60 min). Naps’ proximity to the night sleep episode was defined as “early” (≥7 h) and “late” (