Reduced impact of alcohol use on next-day tiredness in older relative to younger adults: A role for sleep duration.

Recent work has suggested that older adults may be less susceptible to the next-day effects of alcohol relative to younger adults. The effects of alcohol in younger adults may be mediated by sleep duration, but due to age differences in the contexts of alcohol use, this mediation process may not generalize to older adults. The present study examined age-group (younger vs. older adults) differences in how alcohol use influenced next-day tiredness during daily life. Reports of alcohol use, sleep duration, and next-day tiredness obtained on ∼101 days from 91 younger adults (ages 20-31 years) and 75 older adults (ages 65-80 years) were modeled using a multilevel, moderated mediation framework. Findings indicated that (a) greater-than-usual alcohol use was associated with greater-than-usual tiredness in younger adults only, (b) greater-than-usual alcohol use was associated with shorter-than-usual sleep duration in younger adults only, and (c) shorter-than-usual sleep duration was associated with greater tiredness in both younger and older adults. For the prototypical younger adult, a significant portion (43%) of the association between alcohol use and next-day tiredness could be explained assuming mediation through sleep duration, whereas there was no evidence of mediation for the prototypical older adult. Findings of age differences in the mediation process underlying associations among alcohol use, sleep, and tiredness provide insight into the mechanisms driving recent observations of reduced next-day effects of alcohol in older relative to younger adults. (PsycINFO Database Record (c) 2017 APA, all rights reserved).