Light, physical activity reduces brain aging

April 19, 2019

Science Daily/Boston University School of Medicine

Incremental physical activity, even at light intensity, is associated with larger brain volume and healthy brain aging.

Considerable evidence suggests that engaging in regular physical activity may prevent cognitive decline and dementia. Active individuals have lower metabolic and vascular risk factors and these risk factors may explain their propensity for healthy brain aging. However, the specific activity levels optimal for dementia prevention have remained unclear.

The new 2018 Physical Activity-Guidelines for Americans suggest that some physical activity is better than none, but achieving greater than 150 minutes of moderate-to-vigorous (MV) physical activity per week is recommended for substantial health benefits.

Using data from the Framingham Heart Study, researchers found that for each additional hour spent in light-intensity physical activity was equivalent to approximately 1.1 years less brain aging.

According to the researchers, these results suggest that the threshold of the favorable association for physical activity with brain aging may be at a lower, more achievable level of intensity or volume.

"Every additional hour of light intensity physical activity was associated with higher brain volumes, even among individuals not meeting current Physical Activity-Guidelines. These data are consistent with the notion that potential benefits of physical activity on brain aging may accrue at a lower, more achievable level of intensity or volume," explained Nicole Spartano, PhD, research assistant professor of medicine at Boston University School of Medicine (BUSM).

"We have really only just begun to uncover the relationship between physical activity and brain health." Spartano emphasizes the need to explore the impact of physical inactivity on brain aging in different race, ethnic, and socio-economic groups. She is leading a team effort to investigate these patterns at multiple sites all over the country. "We couldn't do this research without the commitment of the Framingham Heart Study participants who have given so much to the medical community over the years. Our research also hinges on the multi-disciplinary team of investigators at Boston University and external collaborators." She also acknowledges the importance of funding for research in this area and is grateful for support from the National Institute on Aging, American Heart Association, and Alzheimer's Association.

https://www.sciencedaily.com/releases/2019/04/190419112331.htm

Exercise offers protection against Alzheimer's

July 16, 2019

Science Daily/Massachusetts General Hospital

Higher levels of daily physical activity may protect against the cognitive decline and neurodegeneration (brain tissue loss) from Alzheimer's disease (AD) that alters the lives of many older people, researchers from Massachusetts General Hospital (MGH) have found. In a paper in JAMA Neurology, the team also reported that lowering vascular risk factors may offer additional protection against Alzheimer's and delay progression of the devastating disease. The findings from this study will be presented at the Alzheimer's Association International Conference (AAIC) in Los Angeles by the first author of the study, Jennifer Rabin, PhD, now at the University of Toronto, Sunnybrook Research Institute.

"One of the most striking findings from our study was that greater physical activity not only appeared to have positive effects on slowing cognitive decline, but also on slowing the rate of brain tissue loss over time in normal people who had high levels of amyloid plaque in the brain," says Jasmeer Chhatwal, MD, PhD of the MGH Department of Neurology, and corresponding author of the study. The report suggests that physical activity might reduce b-amyloid (Ab)-related cortical thinning and preserve gray matter structure in regions of the brain that have been implicated in episodic memory loss and Alzheimer's-related neurodegeneration.

The pathophysiological process of AD begins decades before clinical symptoms emerge and is characterized by early accumulation of b-amyloid protein. The MGH study is among the first to demonstrate the protective effects of physical activity and vascular risk management in the "preclinical stage" of Alzheimer's disease, while there is an opportunity to intervene prior to the onset of substantial neuronal loss and clinical impairment. "Because there are currently no disease-modifying therapies for Alzheimer's disease, there is a critical need to identify potential risk-altering factors that might delay progression of the disease," says Chhatwal.

The Harvard Aging Brain Study at MGH assessed physical activity in its participants -- 182 normal older adults, including those with elevated b-amyloid who were judged at high-risk of cognitive decline -- through hip-mounted pedometers which counted the number of steps walked during the course of the day.

"Beneficial effects were seen at even modest levels of physical activity, but were most prominent at around 8,900 steps, which is only slightly less than the 10,000 many of us strive to achieve daily," notes co-author Reisa Sperling, MD, director of the Center for Alzheimer's Research and Treatment, Brigham and Women's Hospital and Massachusetts General Hospital and co-principal investigator of the Harvard Aging Brain Study.

Interventional approaches that target vascular risk factors along with physical exercise have added beneficial properties, she adds, since both operate independently. Vascular risk factors measured by the researchers were drawn from the Framingham Cardiovascular Disease Risk Score Calculator, and include age, sex, weight, smoking/non-smoking, blood pressure, and whether people are on treatment for hypertension.

Through ongoing studies MGH is working to characterize other forms of physical activity and lifestyle changes that may help retard the progress of Alzheimer's disease. "Beta amyloid and tau protein build-up certainly set the stage for cognitive impairment in later age, but we shouldn't forget that there are steps we can take now to reduce the risk going forward -- even in people with build-up of these proteins," says Chhatwal. "Alzheimer's disease and the emergence of cognitive decline is multifactorial and demands a multifactorial approach if we hope to change its trajectory."

https://www.sciencedaily.com/releases/2019/07/190716193543.htm