Walking Away from Sleep Problems and Dementia

Adults age 50 and older who get moderate to vigorous physical activity may be less likely to develop dementia, stroke, anxiety, depression, and sleep disorders, according to a new study.  Researchers found that the more time adults spent sitting, the more likely they were to develop one of these diseases.

“This research highlights the role of physical activity and sedentary behavior as modifiable factors that may enhance brain health and reduce the incidence of these diseases,” said study author Dr. Jia-Yi Wu with Fudan University in Shanghai, China. “It is promising to think that encouraging people to make these lifestyle changes could potentially lessen the burden of these diseases in the future.”

From a large United Kingdom database, researchers looked at data from 73,411 adults (average age of 56) who wore accelerometer devices continuously for seven days. These devices measure physical activity, how much energy used on  activities and how much time spent sitting each day. Metabolic equivalents (METs) were used to quantify energy expenditure. Moderate to vigorous physical activity was defined as activities with an energy expenditure of at least three METs. Walking or cleaning was three METs and more intense exercise like cycling could be around six METs, depending on speed. Adults who had moderate to vigorous physical activity energy expenditure were 14% to 40% less likely to develop the five diseases than those who had lower energy expenditure.

The more time adults spent sitting, the higher their risk of developing one of the diseases, with the increase ranging from 5% to 54% higher than those who spent the least amount of time sitting. “Some previous studies have relied on people reporting on their own levels of activity,”  said Dr. Wu. “With our large number of participants and the use of devices that provide objective measurements of activity levels, these results will have implications for assessing risk factors and developing interventions to prevent the development of these diseases.”

Just Small Amounts of Exercise Produce Big Brain Benefits

Just a little bit of regular exercise could help prevent dementia, even for frail older adults, suggests a new study led by researchers at the Johns Hopkins Bloomberg School of Public Health. The researchers found that engaging in as little as 35 minutes of moderate to vigorous physical activity per week, compared to zero minutes per week, was associated with a 41% lower risk of developing dementia over an average four-year follow-up period. Even for frail older adults and those at elevated risk of adverse health outcomes, greater activity was associated with lower dementia risks.  

The researchers found dementia risk decreased with higher amounts of physical activity. Dementia risks were 60% lower in participants in the 35 to 69.9 minutes of physical activity/week category; 63% lower in the 70 to 139.9 minutes/week category; and 69% lower in the 140 and over minutes/week category. For their analysis, the researchers analyzed a dataset covering nearly 90,000 adults living in the U.K. who wore smart-watch-type activity trackers.

“Our findings suggest that increasing physical activity, even as little as five minutes per day, can reduce dementia risk in older adults,” says study lead author Amal Wanigatunga, an assistant professor in the Bloomberg School’s Department of Epidemiology. “This adds to a growing body of evidence that some exercise is better than nothing, especially with regard to an aging-related disorder that affects the brain that currently has no cure.”

Dementia, usually from Alzheimer’s disease, is one of the most common conditions in adults 50 and older. It is estimated to affect about seven million people in the U.S., including about a third of those who are 85 years or older. Although the risk of dementia rises with age, studies in recent years have suggested that dementia is somewhat preventable within a normal lifespan by lifestyle changes that include better control of cholesterol, blood pressure and blood sugar, and being more active.

The minimum amount of activity needed to reduce dementia risk meaningfully isn’t yet clear. For many older individuals, especially frail ones, the high amounts of exercise recommended in official guidelines are unattainable and may discourage any exercise at all.  The U.S. Department of Health and Human Services and the U.K. National Health System recommend that adults get at least 150 minutes of moderate intensity exercise per week, an average of 20 minutes per day.

For their study, Wanigatunga analyzed data on approximately 500,000 individuals. The dataset for the new study covered 89,667 adults, mostly in their 50s and older, who used wrist-worn accelerometers to track their physical activity for a week. The analysis compared individuals whose trackers showed some weekly moderate to vigorous physical activity to those whose trackers showed none. The associations between higher activity and lower dementia risk were striking. Participants in the lowest activity category, ranging from one to 34.9 minutes per week, had an apparent risk reduction of about 41%.

Wanigatunga notes that the study was not a clinical trial that established causation indicating that exercise reduces dementia risk, but its findings are consistent with that hypothesis. To check the possibility that their findings reflected undiagnosed dementia leading to lower physical activity, the researchers repeated their analysis but excluded dementia diagnoses in the first two years of follow-up. The association between more activity and lower dementia risk remained robust. Wanigatunga and his colleagues recommend that future studies investigate low-dose exercise as an important initial step towards increasing physical activity as a dementia-preventing strategy.

 John Schieszer is an award-winning national journalist and radio and podcast broadcaster of The Medical Minute. He can be reached at medicalminutes@gmail.com