## Middle-aged people not getting enough sleep are less likely to see the benefits of exercise when it comes to protecting against a decline in skills such as memory and thinking, scientists have said.
Researchers from University College London (UCL) found that those in their 50s and 60s who performed regular physical activities but slept less than six hours a night had a faster decline in these skills overall.
The team found that after a decade, their cognitive functions – such as attention, memory, and learning – were the same as those who did less physical activity.
The researchers said their study, published in the Lancet Healthy Longevity journal, highlights the need for sleep to protect against cognitive decline as people get older.
Lead author Dr Mikaela Bloomberg, of UCL Institute of Epidemiology & Health Care, said: “Our study suggests that getting sufficient sleep may be required for us to get the full cognitive benefits of physical activity.
“It shows how important it is to consider sleep and physical activity together when thinking about cognitive health.
“Previous studies examining how sleep and physical activity might combine to affect cognitive function have primarily been cross-sectional – only focusing on a snapshot in time – and we were surprised that regular physical activity may not always be sufficient to counter the long-term effects of lack of sleep on cognitive health.”
### Key Findings from the Study:
– Middle-aged individuals who slept less than six hours a night and engaged in regular physical activity experienced a faster decline in cognitive skills.
– After a decade, their cognitive functions were similar to those who did less physical activity.
– The study emphasizes the importance of sufficient sleep in protecting against cognitive decline as people age.
– Sleep and physical activity should be considered together for optimal cognitive health.
For the study, the team analyzed data from the English Longitudinal Study of Ageing (Elsa) involving nearly 9,000 people aged 50 and over. Cognitive function was assessed over a period of 10 years through memory and verbal fluency tests. Questionnaires were used to determine sleep duration and physical activity levels.
At the beginning of the study, individuals who were more physically active had better cognitive function regardless of their sleep duration. However, over the 10-year period, middle-aged individuals who were more physically active but slept less experienced a more rapid cognitive decline.
Interestingly, for individuals aged 70 and over, the benefits of exercise on cognitive function remained intact, even with shorter sleep duration.
Co-author Prof Andrew Steptoe, of UCL Institute of Epidemiology & Health Care, said: “It is important to identify the factors that can protect cognitive function in middle and later life as they can serve to prolong our cognitively healthy years and, for some people, delay a dementia diagnosis.
“The World Health Organization already identifies physical activity as a way to maintain cognitive function, but interventions should also consider sleep habits to maximize long-term benefits for cognitive health.”
This study sheds light on the complex relationship between sleep, physical activity, and cognitive health. It underscores the importance of prioritizing sufficient sleep alongside regular exercise to promote optimal cognitive function and protect against cognitive decline as individuals age.
