How lack of sleep impacts cognitive benefits of exercise

Regular physical activity may protect against cognitive decline as we get older, but this protective effect may be diminished for people who are not getting enough sleep, according to a new study by UCL researchers.

The study, looked at cognitive function over 10 years in 8,958 people aged 50 and over in England. The research team investigated how different combinations of sleep and physical activity habits might affect people’s cognitive function over time.

They found that people who were more physically active but had short periods of sleep – less than six hours on average – had faster cognitive decline overall, meaning that after 10 years their cognitive function was equivalent to peers who did less physical activity.

The study found, in line with previous research, that sleeping between six and eight hours per night and higher levels of physical activity were linked to better cognitive function.

Those who were more physically active also had better cognitive function regardless of how long they slept at the start of the study. This changed over the 10-year period, with more physically active short sleepers (less than six hours) experiencing more rapid cognitive decline.

Reference: Joint associations of physical activity and sleep duration with cognitive ageing: longitudinal analysis of an English cohort study, The Lancet Healthy Longevity, DOI 10.1016/S2666-7568(23)00083-1