The short-term boost our brains get after we exercise lasts throughout the next day, suggests a new study led by researchers at UCL (University College London).
Previous research in a laboratory setting has shown that people’s cognitive performance improves in the hours after exercise, but how long this benefit lasts is unknown.
The new study, published in the International Journal of Behavioral Nutrition and Physical ActivityResearch found that people aged 50 to 83 who performed more moderate to vigorous physical activity than normal on a given day performed better on memory tests the following day.
Spending less time sitting and sleeping six hours or more were also linked to better scores on memory tests the next day.
Deeper (slow-wave) sleep also contributed to memory function, and the research team found that this explains a small part of the link between exercise and better next-day memory.
The research team looked at data from 76 men and women who wore activity trackers for eight days and took cognitive tests every day.
Our findings suggest that the short-term memory benefits of physical activity may last longer than previously thought, possibly lasting until the next day rather than just hours after exercise. Getting more sleep, especially deep sleep, appears to contribute to this memory improvement.
Moderate or vigorous activity means anything that gets your heart rate up – this could be brisk walking, dancing or climbing a few flights of stairs. It doesn’t have to be a structured exercise.
This was a small study and so needs to be repeated with a larger sample of participants before we can be confident in the results.”
Dr. Mikaela Bloomberg, Lead author, UCL Institute of Epidemiology and Healthcare
In the short term, exercise increases blood flow to the brain and stimulates the release of neurotransmitters such as norepinephrine and dopamine, which support a range of cognitive functions.
These neurochemical changes are believed to last for up to a few hours after exercise. However, the researchers noted that other brain states associated with exercise were longer lasting. For example, there is evidence that exercise can improve mood for up to 24 hours.
A previous study, published by a separate research team in 2016, also found more synchronized activity in the hippocampus (a marker for increased hippocampal function, which facilitates memory function) for 48 hours after high-intensity interval training (HIIT) cycling.
Co-author Professor Andrew Steptoe (UCL Institute of Epidemiology & Health Care) said: “Among older adults, maintaining cognitive function is important for good quality of life, wellbeing and independence. It is therefore useful to identify factors that may influence cognitive health. a daily basis.
“This study provides evidence that the immediate cognitive benefits of exercise may last longer than we thought. It also suggests that good sleep quality individually contributes to cognitive performance.
“However, we cannot determine from this study whether these short-term improvements in cognitive performance contribute to longer-term cognitive health, and while there is ample evidence that physical activity could slow cognitive decline and reduce the risk of dementia, it is still a matter of some debate.”
For the new study, researchers looked at data from wrist-worn activity trackers to determine how much time participants spent being sedentary, engaging in light physical activity, and engaging in moderate or vigorous physical activity. They also quantified sleep duration and time spent in lighter (rapid eye movement or REM) sleep and deeper, slow-wave sleep.
When looking at the links between different types of activity and next-day cognitive performance, the research team took into account a wide variety of factors that may have skewed the results, including the amount of moderate or vigorous physical activity participants did on the day. day of the activity. the tests.
They also took into account the participants’ average activity and sleep quality over the eight days they were followed, because participants who tend to be more active and tend to have higher sleep quality perform better in cognitive tests.
The team found that more moderate or vigorous physical activity compared to a person’s average the next day was linked to better working memory and episodic memory (recollection of events). More sleep in general was linked to improved episodic and working memory and psychomotor speed (a measure of how quickly a person perceives and responds to the environment). More slow-wave sleep was linked to better episodic memory.
Conversely, more time spent sedentary than normal was associated with poorer working memory the next day.
The study is one of the first to evaluate next-day cognitive performance using a “micro-longitudinal” study design in which participants were followed as they went about their normal lives rather than requiring them to remain in a laboratory.
Among the study limitations, the researchers noted that the participants were a cognitively healthy group, meaning the results may not be true for people with neurocognitive disorders.
The study involved researchers from the UCL Institute of Epidemiology & Health Care, the UCL Division of Surgery & Interventional Science and the University of Oxford, and was funded by the UK Economic and Social Research Council (ESRC).