Differences in Weeknight Versus Weekend Self-Reported Sleep Parameters Across Sleep Subgroups

Abstract

Insomnia identity refers to the conviction that one has insomnia, which can occur independently of poor sleep. The present study explored weeknight-weekend differences in sleep as a commonly overlooked factor contributing to night-to-night sleep variability as well as the discordance often documented between sleep and sleep appraisal. Multilevel modeling was used to explore sources of variability (within-person/between-person) and weeknight-weekend differences in outcomes of sleep duration (total sleep time, TST), sleep disturbance (sleep onset latency, SOL; wake after sleep onset, WASO), and sleep timing (bedtime, BT; arising time, AT; mid-sleep time, MST) among four sleep subgroups: noncomplaining good sleepers (NG), complaining poor sleepers (CP), complaining good sleepers (CG), and noncomplaining poor sleepers (NP). Analyses were conducted using an archival dataset of 528 community-dwelling adults who completed 14 days of sleep diaries. Participants were classified according to the presence/absence of a sleep complaint and presence/absence of poor sleep. First, sources of variability (within-person/between-person) were characterized for each sleep parameter among the sleep subgroups, separately. Second, weeknight-weekend differences in sleep were examined among the sleep subgroups by crossing sleep complaint with quantitative sleep status and day-type. Pervasive differences in weeknight versus weekend sleep were not observed among the sleep subgroups; nonetheless, findings did identify a few notable subgroup differences in certain sleep parameters that may contribute to sleep complaint and poor sleep. Specifically, CG exhibited significantly greater WASO than NG on weeknights only. WASO and SOL were each greater among CP than NP across weeknights and weekends. Earlier AT and MST – but not BT– were observed among good sleepers relative to poor sleepers on weeknights only. Within-person differences were greater than between-person differences for TST, SOL, and WASO across sleep subgroups; however, between-person differences exceeded within-person differences for sleep timing outcomes (BT, AT, MST). Findings from this study suggest that (1) differences in certain sleep parameters (WASO, SOL) may contribute to sleep complaint among good and poor sleepers, (2) delayed weekday sleep timing may be an important factor distinguishing between poor and good sleep subgroups, and (3) sources of variability (within-person/between-person) vary depending on both the sleep subgroup and sleep parameter being examined.