A recent study indicates that insufficient sleep may undermine the cognitive advantages of regular exercise for older adults. Conducted by researchers at UCL, the study examined cognitive performance over a decade among 8,958 English participants aged 50 and older. Findings revealed that individuals who engaged in physical activity but slept less than six hours on average experienced a more rapid cognitive decline, ultimately resembling less active peers after 10 years.

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The research, published in The Lancet Healthy Longevity, showed significant cognitive decline in active individuals aged 50 to 60 who did not get adequate sleep. Conversely, participants aged 70 and above did not exhibit diminished cognitive benefits from exercise, even with shorter sleep duration. Lead author Dr. Mikaela Bloomberg emphasized the need to prioritize both sleep and physical activity for optimal cognitive health. She noted that while previous studies mainly provided a snapshot in time, this longitudinal approach revealed the long-term effects of sleep deprivation on cognitive function, contradicting earlier findings that physical activity alone sufficed in promoting cognitive health.

Participants were categorized based on their sleep duration—short (less than six hours), optimal (six to eight hours), and long (more than eight hours)—and their physical activity levels were assessed. Cognitive function was evaluated through episodic memory and verbal fluency tests. The results indicated that those with high physical activity and short sleep faced accelerated cognitive decline, a pattern not observed in the older age group.

Co-author Professor Andrew Steptoe highlighted the significance of identifying factors that contribute to cognitive health in midlife and beyond, suggesting that physical activity recommendations should also address sleep habits. The study drew on data from the English Longitudinal Study of Ageing, recognizing that self-reported measures of sleep and physical activity could limit findings. Researchers plan to expand future studies to include more diverse populations and utilize objective measures of sleep quality.

This research was funded by the UK’s Economic and Social Research Council.