Fitness trackers reveal links between exercise, memory and mental health

Summary: Specific intensities of exercise over a long period of time are associated with different aspects of memory and mental health.

Source: Dartmouth College

Exercise can improve your cognitive and mental health, but not all forms and intensities of exercise affect the brain equally. 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 Dartmouth study.

The findings are published in Scientific reports and provide information on how the exercise could be optimized.

“Mental health and memory are central to almost everything we do in our daily lives,” says lead author Jeremy Manning, assistant professor of psychological and brain sciences at Dartmouth. “Our study is trying to build a foundation for understanding how different intensities of physical exercise affect different aspects of mental and cognitive health.”

The researchers asked 113 Fitbit users to take a series of memory tests, answer some questions about their mental health and share their fitness data from the previous year. They expected that more active individuals would perform better in memory and mental health, but the results were more nuanced.

People who used to exercise at low intensities performed better on some memory tasks, while those who exercised at high intensities did better on other memory tasks. Participants who were more active also reported higher stress levels, while people who exercised regularly at lower intensities showed lower rates of anxiety and depression.

Previous research has often focused on the effects of exercise on memory over a relatively short period of time over several days or weeks, but the Dartmouth researchers wanted to examine the effects over a much longer time scale.

The data included daily step count, average heart rate, how much time was spent exercising in different “heart rate zones” as defined by FitBit (resting, out of range, fat burning, cardio or peak ) and other information collected during a full calendar year. Study participants were recruited online from Amazon’s Mechanical Turk, a collective workforce.

The four types of memory tasks used in the study were designed to investigate different aspects of the participants’ abilities, at different time scales. Two sets of tasks were intended to test “episodic” memory—the same kind of memory used to remember autobiographical events, like what you did yesterday.

Another set of tasks was designed to test “spatial” memory, the same type of memory used to remember locations, such as where you parked your car. The last set of tasks tested “associative” memory—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 overall, but the specific areas of improvement depended on what type of activity people did.

The researchers found that participants who frequently exercised at moderate intensities tended to perform better on episodic memory tasks, while participants who frequently exercised at high intensities did better on spatial memory tasks. Sedentary participants who rarely exercised tended to perform worse on spatial memory tasks.

Participants who had been more active in the previous year tended to show better memory performance overall, but the specific areas of improvement depended on what type of activity people did. The image is in the public domain

The researchers also identified connections between the participants’ mental health and their memory performance. Participants with self-reported anxiety or depression tended to perform better on the spatial and associative memory tasks, while those with self-reported bipolar disorder tended to perform better on the episodic memory tasks. Participants who reported higher levels of stress tended to perform worse on the 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 are really complicated dynamics at play that can’t be summed up in simple phrases like ‘walking improves memory’ or ‘stress hurts memory,'” he says Manning.

“In contrast, 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 some interesting applications. “For example,” says 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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About this neuroscience research news

Author: Amy Olson
Source: Dartmouth College
Contact: Amy Olson – Dartmouth College
Image: The image is in the public domain

Original Research: Open access
“Fitness Tracking Reveals Task-Specific Associations Between Memory, Mental Health, and Physical Activity” by Jeremy Manning et al. Scientific reports


Summary

Fitness monitoring reveals task-specific associations between memory, mental health, and physical activity

Physical activity can benefit both physical and mental well-being. Different forms of exercise (eg, aerobic versus anaerobic; running versus walking, swimming, or yoga; high-intensity interval training versus resistance training, etc.) affect fitness in different ways. For example, running can substantially affect leg and heart strength, but only moderately affect arm strength.

We hypothesized that the mental benefits of physical activity might be similarly differentiated. We focused specifically on how different intensities of physical activity might relate to different aspects of memory and mental health.

To test our hypothesis, we collected (in total) about a century of fitness data. We then asked participants to fill out surveys asking them to self-report on different aspects of their mental health. We also asked participants to engage in a battery of memory tasks that could test their short- and long-term episodic, semantic, and spatial memory performance.

We found that participants with similar physical activity habits and fitness profiles tended to also show similar mental health and task performance profiles. These effects were task specific, as different patterns of physical activity or fitness characteristics varied with different aspects of memory, in different tasks.

Taken together, these findings provide foundational work for designing physical activity interventions that target specific components of cognitive performance and mental health by leveraging low-cost fitness tracking devices.

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