Skip sleep, increase risk of cognitive decline, research warns middle-aged people

Exercising religiously, eating on time but not taking enough sleep? You might be losing out on benefits when it comes to protecting yourself against the decline in key skills such as memory and thinking, a new study has shown. 

Scientists at the University College London (UCL) highlighted the need for sleep to protect against cognitive decline, in a study published in the journal The Lancet Healthy Longevity. 

The team found that those in their 50s and 60s who were regularly exercising but slept less than six hours a night had a faster decline in motor skills. To arrive at the conclusion, the team peered through data from the English Longitudinal Study of Ageing (Elsa) from nearly 9,000 people aged 50 and over.

After selecting the pool, their cognitive function was assessed over a 10-year-long period. Questionnaires were presented to better understand how long they slept and whether it was less or more than six hours. 

Interestingly, during the initial phase of the experiment, those who were physically more active had better cognitive skills, regardless of sleep duration. However, this changed over the 10-year period when short sleepers in their late 50s and early 60s experienced a rapid cognitive decline. 

“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," said Dr Mikaela Bloomberg, the lead author of the study.

“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," he added.

While those in their 50s and 60s needed to sleep more to achieve cognitive nirvana, the study showed that people aged 70 and over had cognitive functions maintained, despite short sleep cycles. 

“The World Health Organisation already identifies physical activity as a way to maintain cognitive function, but interventions should also consider sleep habits to maximise long-term benefits for cognitive health,” said Prof Andrew Steptoe, the co-author of the study.