How much does sleep vary from night‐to‐night? A quantitative summary of intraindividual variability in sleep by age, gender, and racial/ethnic identity across eight‐pooled datasets

Abstract

Summary Habitual sleep duration and efficiency vary widely by age, gender, and racial/ethnic identity. Despite growing research on the importance of night‐to‐night, intraindividual variability (IIV) in sleep, few studies have examined demographic differences in sleep IIV. The present study describes typical sleep IIV overall and by demographics among healthy sleepers. Eight datasets of healthy sleepers (N = 2,404; 26,121 total days of sleep data) were synthesised to examine age, gender, and racial/ethnic identity differences in sleep IIV measured via diaries, actigraphy, and electroencephalography (EEG). Sleep IIV estimates included the intraindividual standard deviation (iSD), root mean square of successive differences (RMSSD), coefficient of variation (CV), and a validated Bayesian Variability Model (BVM). There was substantial IIV in sleep across measurement types (diary, actigraphy, EEG) for both sleep duration (iSD: 85.80 [diary], 77.41 [actigraphy], 67.04 [EEG] minutes; RMSSD: 118.91, 108.89, 91.93 minutes; CV: 19.19%, 19.11%, 18.57%; BVM: 60.60, 58.20, 48.60 minutes) and sleep efficiency (iSD: 5.18% [diary], 5.22% [actigraphy], 6.46% [EEG]; RMSSD: 7.01%, 7.08%, 8.44%; CV: 5.80%, 6.27%, 8.14%; BVM: 3.40%, 3.58%, 4.16%). Younger adults had more diary and actigraphy sleep duration IIV. Gender differences were inconsistent. White and non‐Hispanic/Latinx adults had less IIV in sleep duration and efficiency compared to racial/ethnic minority groups. Even among healthy sleepers, sleep varies widely from night‐to‐night. Like mean sleep, there also may be disparities in IIV in sleep by demographic characteristics. Study results help characterise normative values of sleep IIV in healthy sleepers.

Objective and Subjective Intraindividual Variability in Sleep: Predisposing Factors and Health Consequences

“…The current work focused on IIV in sleep duration rather than other possible measures to constrain analyses and determine whether IIV in TSTs was conceptually distinguishable from mean TST. To estimate IIV, we computed the individual standard deviation (ISD) of the seven TSTs (10,31). To determine if a simpler VAS approach produced comparable outcomes, we also had participants rate from 0 to 100 the consistency of their overall sleep patterns across weekdays as well as rate their consistency between weekdays and weekends.…”

“…As such, a participant who sleeps 7 hours every night will often be treated the same as a participant who oscillates between restriction (5 hours) and recovery (9 hours) sleep every night because both participants averaged 7 hours. There is growing evidence, however, that irregular sleep habits are common in the population and that intraindividual variability in sleep (IIV) could be a key dimension of overall sleep health (8,10). Greater IIV (i.e., irregular sleep patterns) has been associated with adverse health consequences such as risk for cardiovascular disease (11,12), poor metabolic health (13,14), depression (15)(16)(17), worse stress regulation (18), worse cognitive functioning (13), greater daytime sleepiness (19), poorer academic performance (20), and greater mortality (21).…”

Using a frequentist and Bayesian approach to examine video game usage, substance use, and sleep among college students

“…First, until recently, sleep research has tended to use one-time retrospective questionnaires to assess typical sleep patterns. However, sleep varies substantially from night to night in young adults (Messman et al, 2022). Variability in sleep measures may provide unique, valuable information that is missed by using retrospective measures or average sleep patterns (Schick et al, 2022).…”

Day‐to‐day sleep variability with Alzheimer's biomarkers in at‐risk elderly

“…Adults show important day‐to‐day variability in sleep characteristics, 5 which could reflect circadian dysfunctions and intermittent sleep restriction hidden by averaged values. Sleep loss and circadian deregulation have the potential to promote AD pathology 6,7 .…”