Meta-analysis of quantitative sleep parameters from childhood to old age in healthy individuals: developing normative sleep values across the human lifespan.
Level 1 - systematic review of randomized trials
Meta-analysis of observational studies (graded Level 1 by design analogy)
PubMed 15586779 · doi:10.1093/sleep/27.7.1255
What was done
Systematic review and meta-analysis of peer-reviewed articles published between 1960 and 2003 evaluating objective sleep parameters across the lifespan. The analysis synthesized 65 studies comprising 3,577 healthy nonclinical participants aged 5 to 102 years with all-night polysomnography or actigraphy measuring sleep latency, sleep efficiency, total sleep time, sleep stages (1, 2, slow-wave, REM), REM latency, and wake after sleep onset.
What was found
In children and adolescents, total sleep time decreased with age only in school-day studies, slow-wave sleep percentage negatively correlated with age, and stage 2 and REM percentages changed significantly with age. In adults, total sleep time, sleep efficiency, slow-wave sleep percentage, REM sleep percentage, and REM latency all significantly decreased with age, while sleep latency, stage 1 percentage, stage 2 percentage, and wake after sleep onset significantly increased. After age 60, only sleep efficiency continued to decrease significantly. Exact numerical effect sizes were not reported in the abstract. Effect size magnitudes changed depending on whether studies screened for mental disorders, organic diseases, substance use, or sleep apnea.
Why it matters
This study provides normative reference trajectories for objective sleep architecture across the human lifespan. It demonstrates that age-related sleep changes are progressive but heavily confounded if subclinical medical and sleep disorders are not rigorously excluded.
Limits
The abstract reports no numerical values, confidence intervals, or exact effect sizes. Data were sparse for school-aged children, adolescents, and middle-aged adults, and very few studies examined the effect of race. Variability in screening criteria for medical, psychiatric, and sleep disorders across studies significantly altered observed effect sizes.
Cited by
- contradicts As people get older, sleep quality tends to decline even though sleep duration or quantity may increase.