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Exercise linked to greater gray matter volume, reduced Alzheimer's risk

Burning calories through any variety of exercises or physical activity is related to larger gray matter volumes among the elderly, regardless of cognitive status, and may moderate neurodegeneration, according to data published in the Journal of Alzheimer’s Disease.

“As of 2013, there were an estimated 44.4 million people worldwide with dementia,” Cyrus A. Raji, MD, PhD, of the department of radiology at UCLA Medical Center, in Los Angeles, and colleagues wrote. “This number will increase to an estimated 75.6 million in 2030, and 135.5 million in 2050. Unfortunately for those with Alzheimer’s disease, pharmacological agents temporarily treat symptoms without having an effect on the underlying pathophysiology of the disease.”

To determine the predictive relationship between physical activity, measured by caloric expenditure, and gray matter volumes, among those who are cognitively impaired and those who are not, the researchers analyzed an 876-participant subsample of the Cardiovascular Health Study, a multisite, population-based longitudinal study in people aged 65 years and older.

Members of the subsample all had their energy output measured, in kilocalories per week; been classified as having normal cognition, mild cognitive impairment or Alzheimer’s disease; and undergone volumetric brain MRI. The researchers’ models examined the relationship between kilocalories per week exerted and gray matter volumes reported in the brain imaging, accounting for covariates that included head size, age, sex, white matter hyperintensity lesions, mild cognitive impairment or Alzheimer’s status, and site.

According to the researchers, greater energy output was associated with larger gray matter volumes in the frontal, temporal and parietal lobes, and the hippocampus, thalamus and basal ganglia. In addition, burning more calories slowed neurodegeneration through gray-matter volume loss in the precuneus, posterior cingulate and cerebellar vermis.

“With the elderly population growing rapidly, a better understanding of preventive measures for maintaining cognitive function is crucial,” Raji and colleagues wrote. “Studies such as this one suggest that simply caloric expenditure, regardless of type or duration of exercise, may alone moderate neurodegeneration and even increase [gray matter] volume in structure of the brain central to cognitive functioning.” – by Jason Laday

Disclosure: Raji reports receiving consulting fees from Brainreader ApS and the Change Your Brain Change Your Life Foundation. No other researchers report any relevant financial disclosures.