Sleep more to see the benefits of exercise

New research by University College London (UCL) has found that people in their 50s and 60s who perform regular physical activities but sleep less than six hours a night have a faster decline in skills such as memory and thinking than those who sleep longer but 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, suggesting that getting sufficient sleep is required to get the full cognitive benefits of physical activity.

For the study, the team looked at data from the English Longitudinal Study of Ageing (Elsa) from nearly 9,000 people aged 50 and over. Their cognitive function was assessed over a period of 10 years with various memory and verbal fluency tests.

Questionnaires were also used to assess how long they slept and whether this was less or more than six hours. People were also asked about their levels of physical activity.

At the start of the study, those who were more physically active had better cognitive function regardless of how long they slept. However, this changed over the 10-year period, with more physically active short sleepers in their 50s and 60s experiencing more rapid cognitive decline.

For people aged 70 and over, the benefits of exercise on cognitive function were maintained, despite shorter sleep.

The World Health Organisation identifies physical activity as a way to maintain cognitive function, but it would seem from this new research that interventions should also consider sleep habits to maximise long-term benefits for cognitive health.