Exercise delays dementia but only if we sleep on it

Exercise may stave off dementia, but only in combination with sufficient sleep, research has found.

People in their 50s and 60s who did a lot of exercise but had fewer than six hours of sleep on average saw rapid cognitive decline over the 10 years, a study found.

Exercise may stave off dementia, but only in combination with sufficient sleep, research has found.

A team from UCL followed 9000 people in England aged 50 and above for a decade.

Those who had between six and eight hours of sleep fared better on tests of cognitive performance, as did the most physically active participants.

People in their 50s and 60s who did a lot of exercise but had fewer than six hours of sleep on average saw rapid cognitive decline over the 10 years, akin to those who were less active.

Andrew Steptoe of UCL’s Institute of Epidemiology and Health Care, a co-author on the paper, said: “It is important to identify factors that can protect cognitive function in middle and later life as they can serve to prolong cognitively healthy years and … delay a dementia diagnosis.

“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.”

For those over 70, the benefits of exercise continued even without sleep.

The study is published in The Lancet Healthy Longevity. It used data from the English longitudinal study of ageing, which recorded how long people slept and how physically active they were. Those who slept fewer than six hours on an average weeknight were classed as “short” sleepers, those who got six to eight hours “optimal”, and those who got more than eight hours “long”.

The top third most active were compared with the less active.

Mikaela Bloomberg, the lead author, also of UCL, said: “Our study suggests 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.”

The Times