Exercise can improve your cognitive and mental health –; but not all forms and intensities of exercise have the same effect on the brain. The effects of exercise are much more nuanced, as specific intensities of exercise over a long period of time are associated with different aspects of memory and mental health, according to a new study from Dartmouth. The results are published in Scientific reports and provide insight into how the exercise could be optimized.
Mental health and memory are central to almost everything we do in our daily lives. Our study attempts to lay the groundwork for understanding how different physical exercise intensities affect different aspects of mental and cognitive health. »
Jeremy Manning, lead author, assistant professor of psychology and brain science, Dartmouth College.
The researchers asked 113 Fitbit users to complete a series of memory tests, answer some questions about their mental health, and share their fitness data from the previous year. They expected more active people to have better memory performance and mental health, but the results were more nuanced. People who tended to exercise at low intensity performed better on some memory tasks, while those who exercised at high intensity performed better on other memory tasks. Participants who engaged in more intense physical activity also reported higher levels of stress, while people who exercised regularly at lower intensities had lower levels of anxiety and depression.
Previous research has often looked at the effects of exercise on memory over a relatively short period of days or weeks, but the Dartmouth researchers wanted to examine the effects over a much longer timescale. The data included daily step counts, average heart rates, time spent exercising in different “heart rate zones” defined by FitBit (resting, out of bounds, fat burning, cardio or peak), as well as than other information collected over a full calendar year. Study participants were recruited online from Amazon’s Mechanical Turk, a crowdsourced workforce.
The four types of memory tasks used in the study were designed to probe different aspects of participants’ abilities, over different time scales. Two sets of tasks were designed to test “episodic” memory, that is, the type of memory used to recall autobiographical events, such as what you did yesterday. Another set of tasks was designed to test “spatial” memory, which is the type of memory used to remember places, such as where you parked your car. The final set of tasks tested “associative” memory, that is, the ability to remember connections between concepts or other memories.
Participants who had been more active in the previous year tended to show better memory performance in general, but the specific areas of improvement depended on the types of activity they engaged in. Researchers found that participants who exercised frequently at moderate intensity tended to perform better on episodic memory tasks, while participants who exercised frequently at high intensity performed better. results in spatial memory tasks. Sedentary participants who rarely exercised tended to perform worse on spatial memory tasks.
The researchers also identified links between the participants’ mental health and their memory performance. Participants who reported being anxious or depressed tended to perform better on spatial and associative memory tasks, while those who reported having bipolar disorder tended to perform better on episodic memory tasks. Participants who reported higher stress levels tended to perform worse on associative memory tasks.
The team has made all of its data and code freely available on Github for anyone who wants to explore or better understand the dataset.
“When it comes to physical activity, memory and mental health, there’s a really complicated dynamic at play that can’t be summed up in single phrases like ‘walking improves your memory’ or ‘stress hurts to your memory,'” Manning explains. “Rather, specific forms of physical activity and specific aspects of mental health appear to affect each aspect of memory differently. »
With further research, the team says their findings could have exciting applications. “For example, continues Manning, to help students prepare for an exam or reduce their symptoms of depression, specific exercise regimens could be designed to help improve their cognitive performance and mental health. »
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Journal reference:
Manning, J.R., et al. (2022) Fitness tracking reveals task-specific associations between memory, mental health, and physical activity. Scientific reports. doi.org/10.1038/s41598-022-17781-0.