Research
Mixed
Younger age is consistently associated with greater variability in sleep timing (bedtime and wake time), while older age is associated with less variable sleep patterns.
Young adults naturally have more erratic sleep schedules. This is normal but carries health risks. As you age, your sleep tends to stabilize. If you are young, be aware that your erratic sleep may be harming your health more than you think.
GoodSupportsHIGH confidence
In both community [36e38] and outpatient insomnia [5] samples, younger age was consistently associated with more variable self-report bedtime (BT) and rise-time (RT).
Why this rating
Consistent findings across multiple studies in the review.
Source
Beyond the mean: A systematic review on the correlates of daily intraindividual variability of sleep/wake patterns
Bei Bei et al. · Sleep Medicine Reviews · 2015
DOI 10.1016/j.smrv.2015.06.003
systematic_reviewCited 429×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
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- Greater day-to-day intraindividual variability (IIV) in sleep/wake patterns (timing, duration, quality) is consistently associated with poorer physical and mental health outcomes, including higher BMI, obesity, chronic disease, depression, and stress, independent of mean sleep values.Good
- Sleep interventions, particularly Cognitive Behavioral Therapy for Insomnia (CBT-I), reduce sleep/wake intraindividual variability (IIV), suggesting that stabilizing sleep patterns is a key mechanism of these treatments.Good
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