Alzheimer’s risk may be halved with increased physical activity

Written by Lauren Pulling

New research conducted by investigators at UCLA Medical Center (CA, USA) and the University of Pittsburgh (PA, USA) is the first to address the longitudinal relationship between physical activity and gray matter volume in a large-scale elderly cohort, demonstrating increased gray matter volume and up to 50% reduction in the risk of developing Alzheimer’s Disease (AD) in more active individuals.
Previous studies have highlighted the benefit of physical activity in maintaining and improving brain health, yet several questions have remained unanswered. Lead author Cyrus A. Raji and his team (University of California, Los Angeles; CA, USA) studied a total of 876 participants across multiple sites. The participants, with an average age of 78 years, were taken from a long-term cohort of patients in the 30 year Cardiovascular Health Study.

Participants recorded any kind of physical activity (such as dancing, cycling and gardening) using a standardized questionnaire and the information was then converted into approximate caloric expenditure. Participants also underwent volumetric MRI and cognitive assessments were carried out to classify normal cognition, mild cognitive impairment, and AD.

The researchers analyzed caloric output against brain volume changes and found increasing physical activity correlated with larger gray matter volumes in frontal, temporal and parietal lobes. They observed that this included areas implicated in memory, such as the hippocampus.

Notably, participants who both increased their aerobic physical activity and displayed a benefit in brain volume also experienced a 50% reduction in their risk of developing AD. Additionally, those classified as having mild cognitive impairment associated with AD (approximately 25% of the cohort) also benefited from higher brain volume in line with increasing physical activity.

This research, published in the Journal of Alzheimer’s Disease, marks a significant step in our understanding of the link between lifestyle and AD risk,raising the possibility that caloric output could be utilized as a predictive measure of an individual’s risk of developing AD.

George Perry, Editor in Chief of the Journal of Alzheimer’s Disease, said of the new research, “Currently the greatest promise in AD research is lifestyle intervention including increased exercise. Raji et al. present a landmark study that links exercise to increases in gray matter and opens the field of lifestyle intervention to objective biological measurement.”

Source: IOS Press press release; Raji CA et al. Longitudinal Relationships between Caloric Expenditure and Gray Matter in the Cardiovascular Health Study. Journal of Alzheimer’s Disease. doi: 10.3233/JAD-160057 (2016) (Preprint).