Breaking the nap habit: one-year nap restriction mitigates memory decline in older adults.

Abstract

Increased napping in later life is a common behaviour shaped by cultural, environmental and biological factors. Although brief naps can enhance alertness and memory, epidemiological evidence suggests that frequent or prolonged daytime sleep in older adults is associated with poorer physical health and accelerated cognitive decline, including episodic memory, possibly due to the underlying circadian disruption of the sleep-wake cycle. In this study, we tested whether restricting nap habits for 12 months would mitigate the age-related changes in cognitive functioning in healthy retirees (59-82 years). Fifty-eight habitual nappers were randomised either to a nap-control condition (n = 28), where they continued their usual nap routine, or to a nap-intervention condition (n = 30), where they received behavioural coaching to reduce the frequency and duration of daytime napping. A non-nappers group (n = 29) served as a reference. Cognitive performance, with a focus on episodic memory, was assessed at baseline and after the one-year intervention. Actimetric recordings showed that nap-intervention significantly decreased estimates of daytime nap frequency and duration throughout the study. Overall cognitive performance tended to decrease after a year in all participants, but the nap-control group exhibited a significantly greater decline in verbal episodic memory recall as compared to both non-nappers and nap-intervention participants. These results demonstrate that sleep-wake behaviour in older adults can be modified and suggest that targeted nap reduction may offer an accessible strategy to mitigate age-related decline in specific cognitive domains, regardless of whether habitual napping represents a causal or compensatory factor of neurobiological vulnerability.