Meta-analysis of age and actigraphy-assessed sleep characteristics across the lifespan

Study Objectives Sleep quantity and continuity vary across the lifespan. Actigraphy is a reliable and widely used behavioral measure of sleep in research and personal health monitoring. This meta-analysis provides a novel examination of whether age (in years) is associated with actigraphy-assessed sleep across the lifespan. Methods A systematic search of PubMed, Embase.com, Cochrane CENTRAL, and PsycINFO using “actigraphy” and “sleep” terms provided 7079 titles/abstracts; studies of individuals with known psychiatric or medical comorbidities were excluded. Ninety-one articles (N = 23 365) provided data for six meta-analyses examining sleep duration (k = 89), sleep efficiency (k = 58), bedtime (k = 19) and waketime (k = 9) for individuals ages 6–21, and bedtime (k = 7) and waketime (k = 7) for individuals ages 22 and older. Results At older ages, sleep duration was shorter (r = −0.12) and sleep efficiency was lower (r = −0.05). Older age was associated with later bedtime (r = 0.37) and wake-up time (r = 0.24) from ages 6–21, whereas older age was associated with earlier bedtime (r = −0.66) and wake-up time (r = −0.59) for ages 22 and above. The strength of these associations was modified by study continent, but not by any other moderator. Conclusions Age was negatively associated with actigraphy-assessed sleep duration and efficiency, but the effects were small in magnitude. On the other hand, large associations were observed between age and sleep timing, despite a smaller literature and the absence of analyzable data for ages 30–60. Changes in sleep timing, rather than changes in sleep duration or continuity, may better characterize the effects of age on human sleep.