Regular physical activity linked to increased brain volumes in key areas associated with memory and learning

Researchers have discovered a significant correlation between regular physical activity and increased brain volumes. The study, published in the Journal of Alzheimer’s Disease, suggests that even moderate exercise could have a profound impact on brain health, particularly in areas vulnerable to aging and neurodegenerative diseases like Alzheimer’s.

A growing body of evidence suggests a link between physical activity and brain health. With an aging global population and increasing rates of dementia, including Alzheimer’s disease, understanding how lifestyle factors like exercise can impact brain health is of paramount importance. Previous research had hinted at the protective effects of exercise on the brain, but there was a need for a more comprehensive analysis using advanced imaging techniques and a large participant base.

The study involved a large cohort of 10,125 participants, drawn from various locations including Vancouver, Redwood City, Los Angeles, Minneapolis, Boca Raton, and Dallas. This diverse participant pool was crucial for obtaining a broad and representative sample, encompassing a range of ages, genders, races, and ethnicities.

The core of the study’s methodology revolved around magnetic resonance imaging (MRI). Participants underwent non-contrast whole body MRI scans using 1.5T whole body scanners from Philips and Siemens. These high-resolution scanners are capable of producing detailed images of the brain, essential for accurate volumetric analysis. The volumetric measurement of brain regions was conducted using FastSurfer, an advanced deep learning network. This technology is a breakthrough in the field of neuroimaging, as it allows for the rapid, automated analysis of structural MRIs.

Physical activity data were collected through self-reported questionnaires completed prior to imaging. The research team categorized physical activity intensity based on standard definitions from the Centers for Disease Control.

Moderate physical activity was defined as activities that increased heart rate and respiratory rate but still allowed for talking, such as brisk walking or bicycling at a leisurely pace. Vigorous physical activity, in contrast, was more strenuous and would not allow for speaking more than a few words without pausing for breath. The frequency of such activities was also recorded, with participants reporting the number of days they engaged in such activities over a 14-day period.

Larger Brain Volumes in Active Individuals

The researchers found that those who engaged in regular physical activity had significantly larger volumes of gray and white matter. Gray matter is crucial for processing information in the brain, while white matter facilitates the connection between different brain regions.

Study co-author Somayeh Meysami, an assistant professor at Saint John’s Cancer Institute and the Pacific Brain Health Center noted, “Our research links regular physical activity to larger brain volumes, suggesting neuroprotective benefits. This large sample study furthers our understanding of lifestyle factors in brain health and dementia prevention.”

Interestingly, the study highlighted that even moderate levels of physical activity, such as walking less than 4,000 steps a day, could positively impact brain health. This is a particularly important finding, as it suggests that the benefits of exercise on the brain are accessible even at lower, more achievable levels of physical activity for the general population.

“This research underscores the potential neuroprotective effects of exercise, opening new avenues in preventing neurodegenerative diseases,” explained lead author Cyrus A. Raji, an associate professor of radiology and a principal investigator in the Neuroimaging Labs Research Center at Washington University School of Medicine in St. Louis.

“Specifically, it demonstrates that even a low threshold of physical activity – as little as 25 minutes a week or 10 minutes a day for 2.5 days a week – correlates to larger brain volumes in this population of adults throughout the lifespan.”

“Physical activity regimens, especially using historic recommendations such as 150 minutes a week or 10,000 steps a day, can be difficult to establish and maintain. Personally, it takes me about 90 minutes to walk 10,000 steps alone – doable but not easy. Our work suggests that the brain health benefits of physical activity are potentially attainable with a time commitment and intensity of exercise much easier than previously thought.”

Effects on Areas Vulnerable to Alzheimer’s Disease

The study also focused on regions of the brain that are particularly vulnerable to neurodegeneration, such as those affected in Alzheimer’s disease. It was found that the physically active group had larger volumes in the hippocampus, posterior cingulate gyrus, and precuneus. These areas are essential for memory and cognitive function, and their increased volume in physically active individuals suggests a potential protective effect of exercise against age-related cognitive decline and neurodegenerative diseases.

Given the established link between loss of brain volume and cognitive decline or dementia, these findings are particularly significant. They suggest that regular physical activity could be a key factor in maintaining brain volume and, by extension, protecting against cognitive decline and dementia. This aligns with previous research indicating the neuroprotective benefits of exercise and offers a non-pharmacological approach to dementia prevention.

“This study demonstrates the influence of exercise on brain health imaging and when added to other studies on the role of diet, stress reduction and social connection offer the proven benefits of drug-free modifiable factors in substantially reducing Alzheimer’s disease,” said George Perry, editor-in-chief of Journal of Alzheimer’s Disease.

“With comprehensive imaging scans, our study underscores the interconnected synergy between the body and the brain. It echoes the knowledge of past generations, showcasing that increased physical activity is a predictor of a healthier aging brain,” added Rajpaul Attariwala, senior author of the paper.

Limitations and Future Research

Despite the study’s significant findings, there are limitations to consider. The cross-sectional design means that the data represents a snapshot in time, rather than tracking changes over a prolonged period. Additionally, the reliance on self-reported physical activity data introduces the potential for bias, as participants might not accurately remember or report their exercise habits. The study also did not account for a lifetime of physical activity, which could have a considerable impact on brain health.

Looking ahead, future research should aim to address these limitations. Longitudinal studies, tracking participants over time, would provide more definitive evidence of the long-term impacts of physical activity on brain health. Furthermore, objective measures of physical activity, such as wearable fitness trackers, could offer more precise data. Another important avenue of research is exploring the specific biological mechanisms through which exercise influences brain health, which could lead to targeted interventions for dementia prevention.

“This study is cross-sectional so future work should examine longitudinal factors,” Raji said.

The study, “Exercise-Related Physical Activity Relates to Brain Volumes in 10,125 Individuals“, was authored by Cyrus A. Raji, Somayeh Meysami, Sam Hashemi, Saurabh Garg, Nasrin Akbari, Ahmed Gouda, Yosef Gavriel Chodakiewitz, Thanh Duc Nguyen, Kellyann Niotis, David A. Merrill, and Rajpaul Attariwala.