The Effects of Exercise on Cognition
Post by Shireen Parimoo
What's the science?
Exercise has a positive impact not only on our physical health but also our mental health and cognitive abilities. For example, exercise might protect against cognitive decline in older age and may be an effective treatment option for major depressive disorder. However, research on the cognitive benefits of exercise is not always clear-cut. Does exercise really enhance cognition in healthy individuals? This week in Nature Human Behavior, Ludyga and colleagues conducted a meta-analysis of previous studies to determine whether exercise has a beneficial effect on cognitive performance.
What do we already know?
Research on this topic is mixed, with some studies reporting positive effects of exercise on cognitive performance and others finding no effect. This is because the results not only vary depending on the type, intensity, duration, and frequency of exercise but also factors like someone’s age and sex. For example, some studies find that endurance exercises like running and swimming are better for cognitive outcomes than strength-based exercises, while other studies suggest that both are equally effective. Similarly, different studies report opposite effects of exercise on men and women, but they differ in the age groups of their participants. As it’s not feasible to include all of these variables in a single experiment, most studies – including previous meta-analyses – only examined a limited number of these variables, making it difficult to draw a definitive conclusion on the topic.
What’s new?
The authors performed a meta-regression on 80 randomized controlled trials and found that overall, exercise had a small effect on cognitive functions like complex attention, executive functioning, and memory. These effects on cognition were similar after different types of exercise, which included endurance, resistance/strength, and coordinative exercises (e.g. dancing). In short-term exercise programs, short exercise sessions (e.g. 30min) were found to enhance cognitive performance, whereas, in programs lasting longer than 5 months, longer sessions (e.g. 60min) had a larger impact on cognition compared to shorter ones. Interestingly, the effects of different types of exercise and intensity varied based on participant characteristics. Women, children, and older adults saw the greatest effects from low intensity and coordinative exercises, which the authors speculate could be because coordinative exercises pose greater demands on cognition and recruit similar brain regions as cognitive tasks. On the other hand, men were more likely than women to benefit from progressive (becoming more intense over time) and high-intensity exercises of all types.
What's the bottom line?
The effect of exercise on cognition depends on many variables ranging from the type of exercise to someone’s age. Overall, exercise is associated with improvements in cognitive function. These findings have important implications for people’s life outcomes, as cognitive abilities are closely related to school and job performance, as well as for future research to further explore the differential relationship between exercise and cognition in different populations.
Ludyga et al. Systematic review and meta-analysis investigating moderators of long-term effects of exercise on cognition in healthy individuals. Nature Human Behavior (2020). Access the original scientific publication here.