TOPLINE:
Regular moderate to vigorous physical activity predicts larger brain size in key regions, including gray and white matter and the hippocampus, new data suggest.
METHODOLOGY:
- The potential neuroprotective effects of regular physical activity on brain structure are unclear despite reported links between physical activity and reduced dementia risk.
- To investigate, researchers analyzed MRI brain scans from 10,125 healthy adults (mean age, 53 years; 52% male) who self-reported their level of physical activity.
- Moderate to vigorous physical activities, defined as those increasing respiration and pulse rate for at least 10 continuous minutes, was modeled with brain volumes, adjusting for covariates.
- The threshold for defining physically active (vs nonactive) adults was intentionally set at 2.5 days per week, a level far lower than current guidelines.
TAKEAWAY:
- Three quarters of the cohort reported engaging in moderate to vigorous physical activity approximately 4 days per week.
- Physically active adults tended to be younger, with a higher proportion of White individuals, and with lower rates of hypertension and type 2 diabetes.
- After adjusting for multiple factors, increased days of moderate to vigorous activity correlated with larger normalized brain volume in multiple regions including total gray matter; white matter; hippocampus; and frontal, parietal, and occipital lobes.
IN PRACTICE:
"We found that even moderate levels of physical activity, such as taking fewer than 4,000 steps a day, can have a positive effect on brain health. This is much less than the often-suggested 10,000 steps, making it a more achievable goal for many people," co-author David Merrill, MD, with Pacific Brain Health Center, Santa Monica, California, said in a statement.
SOURCE:
The study, with first author Cyrus A. Raji, MD, PhD, Washington University School of Medicine, St. Louis, was published online December 7 in the Journal of Alzheimer's Disease.
LIMITATIONS:
Participants self-reported physical activity in the past 2 weeks, which does not reflect a lifetime of activity levels. The correlation identified between physical activity and brain volumes may not be solely attributable to physical activity alone.
DISCLOSURES:
The study received funding from several health centers and foundations. Raji consults for Brainreader ApS, Neurevolution LLC, Apollo Health, Voxelwise Imaging Technology, and Pacific Neuroscience Foundation and is an editorial board member of the Journal of Alzheimer's Disease but was not involved in the peer-review process.
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