The effect of acute exercise on objectively measured sleep and cognition in older adults

Abstract

BackgroundExercise can improve cognition in aging, however it is unclear how exercise influences cognition, and sleep may partially explain this association. The current study aimed to investigate whether objectively measured sleep mediates the effect of an acute exercise intervention on cognition in older adults.MethodsParticipants were 30 cognitively unimpaired, physically active older adults (69.2 ± 4.3 years) with poor sleep (determined via self-report). After a triple baseline cognitive assessment to account for any natural fluctuation in cognitive performance, participants completed either a single bout of 20-minutes of high intensity exercise on a cycle ergometer, or a control condition, in a cross-over trial design. Cognition was measured immediately post-intervention and the following day, and sleep (total sleep time, sleep onset latency, sleep efficiency, % of rapid eye movement sleep, light sleep and deep sleep) was characterized using WatchPAT™ at baseline (5 nights) and measured for one night after both exercise and control conditions.ResultsResults showed no effect of the exercise intervention on cognition immediately post-intervention, nor an effect of acute exercise on any sleep variable. There was no mediating effect of sleep on associations between exercise and cognition. However, a change from baseline to post-intervention in light sleep and deep sleep did predict change in episodic memory at the ~24 h post-intervention cognitive assessment, regardless of intervention condition.DiscussionThere was no effect of acute high intensity exercise on sleep or cognition in the current study. However, results suggest that associations between sleep and cognition may exist independently of exercise in our sample. Further research is required, and such studies may aid in informing the most effective lifestyle interventions for cognitive health.

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“…The uniqueness of our findings lies in the fact that a single 20-min session of moderate-intensity physical exercise can yield a beneficial effect, similarly in males and females. Notably, this association between exercise (specifically, 20 min of moderate-intensity pedalling) and cognition holds promise, especially when contrasted with the findings of the study by Sewell et al ( 20 ), which showed no immediate positive effect of a 20-min high-intensity pedalling exercise on cognition in older adults. This finding suggests that, particularly for older individuals, moderate exercise may provide greater cognitive benefits compared to high-intensity exercise.…”

“…Conversely, Hubner et al ( 19 ) found no significant benefits on learning consolidation or acquisition immediately after an acute bout of moderate-intensity exercise when compared to controls who did not exercise. Similarly, a recent study by Sewell et al ( 20 ) showed no significant effect on cognition after 20 min of acute exercise at moderate intensity in older adults. While there's substantial evidence to suggest that an acute bout of physical exercise can enhance cognitive performance, the optimal exercise characteristics (e.g., exercise intensity and exercise type) remain elusive.…”