Our brain gets a short-term cognitive boost after exercise, which may last up to 24 hours, according to a study published in the International Journal of Behavioural Nutrition and Physical Activity.
Researchers have known that people’s cognitive performance improves after exercise, but it hasn’t been clear up till now how long this benefit lasts. Now, a team from University College London (UCL) found that, on average, people (aged 50 to 83) who did more moderate to vigorous physical activity than usual on a given day performed better in memory tests the day after. In addition, less time sitting and a good night’s sleep were also linked to better scores in memory tests the next day. As deep sleep after exercise contributes to enhanced memory, the team believes this accounted for a small part of the link between exercise and better next-day memory.
The researchers analysed data from 76 men and women who wore activity trackers for eight days and took cognitive tests daily. The team analysed how much time participants spent sedentary or doing light, moderate, or vigorous physical activity. They also assessed sleep duration and quality, including REM sleep and slow-wave sleep.
Results showed moderate or vigorous physical activity (more than usual) was linked to better memory the next day. More sleep was also linked to better memory, whereas being sedentary worsened memory the next day.
“Our findings suggest that the short-term memory benefits of physical activity may last longer than previously thought, possibly to the next day instead of just a few hours after exercise. Getting more sleep, particularly deep sleep, seems to add to this memory improvement,” said Dr Mikaela Bloomberg from UCL Institute of Epidemiology & Health Care. “Moderate or vigorous activity means anything that gets your heart rate up – this could be brisk walking, dancing, or walking up a few flights of stairs. It doesn’t have to be a structured exercise. This was a small study, so it needs to be replicated with a larger sample of participants before we can be certain about the results.”
In the short term, exercise stimulates blood flow to the brain and triggers the release of neurotransmitters such as norepinephrine and dopamine, which help a range of cognitive functions. These chemical changes only last a few hours after exercise, but researchers noted that other changes caused by exercise last longer. For example, exercise can enhance mood for up to 24 hours.
“Among older adults, maintaining cognitive function is important for good quality of life, wellbeing, and independence. It’s therefore helpful to identify factors that can affect cognitive health on a day-to-day basis,” said Professor Andrew Steptoe from UCL Institute of Epidemiology & Health Care. “This study provides evidence that the immediate cognitive benefits of exercise may last longer than we thought. It also suggests good sleep quality separately contributes to cognitive performance. However, we can’t establish from this study whether these short-term boosts to cognitive performance contribute to longer term cognitive health and though there is plenty of evidence to suggest physical activity might slow cognitive decline and reduce dementia risk, it’s still a matter of some debate.”
Bloomberg, M., Brocklebank, L., Doherty, A. et al. Associations of accelerometer-measured physical activity, sedentary behaviour, and sleep with next-day cognitive performance in older adults: a micro-longitudinal study. Int J Behav Nutr Phys Act 21, 133 (2024). https://doi.org/10.1186/s12966-024-01683-7