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

Physical inactivity and restless sleep exacerbate genetic risk of obesity

Findings reported at ASHG 2017 Annual Meeting

October 20, 2017

Science Daily/American Society of Human Genetics

Low levels of physical activity and inefficient sleep patterns intensify the effects of genetic risk factors for obesity, according to new results.

Andrew Wood, PhD, postdoctoral researcher, who presented the work; Timothy Frayling, PhD, Professor; and their colleagues at the University of Exeter Medical School study the genetics of body mass index (BMI) and Type 2 Diabetes. In the past, Dr. Frayling explained, it has been difficult to measure interactions between genetic risk factors and aspects of environment and lifestyle in a systematic way.

"Until recently, physical activity and sleep patterns could not be measured with as much precision as genetic variants, and we relied on diaries or self-report, which can be very subjective," Dr. Frayling said. In contrast, the new study made use of wrist accelerometer data, which is more objective and quantifiable, and a large genetic dataset from about 85,000 UK Biobank participants aged 40 to 70.

"We wanted to find out if obesity-related genes and activity level have an interactive effect on obesity risk -- if there is a 'double whammy' effect of being both at genetic risk and physically inactive, beyond the additive effect of these factors," said Dr. Wood. The researchers computed a genetic risk score for each participant based on 76 common variants known to be associated with elevated risk of obesity, and analyzed this score in the context of accelerometer data and participants' BMIs.

They found the strongest evidence to date of a modest gene-activity interaction. For example, for a person of average height with 10 genetic variants associated with obesity, that genetic risk accounted for a 3.6 kilogram increase in weight among those who were less physically active but just 2.8 kilograms among those who were more active. Results were similar in analyses of sleep patterns; among participants with some genetic risk of obesity, those who woke up frequently or slept more restlessly had higher BMIs than those who slept more efficiently.

The researchers are currently examining whether this interaction between genetics and physical activity differs between men and women. They are also studying the effects of patterns of activity -- for example, whether a consistent level of moderate activity has different effects from overall low levels punctuated by periods of vigorous activity.

"We hope these findings will inform clinicians who help people lose or maintain their weight, and contribute to the understanding that obesity is complex and its prevention may look different for different people," said Dr. Frayling. "Ultimately, with further research, we may have the scope to personalize obesity interventions," he said.

https://www.sciencedaily.com/releases/2017/10/171020092240.htm