Variability in self-reported normal sleep across the adult age span

Area of Science:

• Gerontology
• Sleep Science
• Psychology

Background:

• Understanding sleep variability is crucial for assessing sleep health across adulthood.
• Previous research often focused on average sleep, overlooking day-to-day fluctuations.

Purpose of the Study:

• To examine within- and between-person differences in sleep parameters.
• To investigate how sleep variability changes across the adult lifespan.

Main Methods:

• Analysis of two-week sleep diary data from 592 healthy adults (ages 20-96).
• Utilized multilevel models and multiple regression to assess variability in total sleep time (TST), nighttime awakenings (NWAK), sleep-onset latency (SOL), and wake-time after sleep onset (WASO).
• Examined variability by age, sex, and race.

Main Results:

• Within-person variability in TST, SOL, and WASO generally exceeded between-person differences.
• Intraindividual variability in TST and NWAK decreased with increasing age.
• Age-related reduction in TST variability was moderated by sex and race, with young Black females exhibiting the highest variability.
• Females generally showed greater intraindividual variability in SOL and NWAK than males.

Conclusions:

• Night-to-night sleep variability is a critical factor in understanding individual sleep differences, especially in older adults.
• Future research should incorporate intraindividual sleep variability alongside average sleep measures for a comprehensive assessment.