Dementia exacts a huge toll, including on families and caregivers. Globally, it affects 5 percent to 8 percent of the population at an estimated annual social cost of more than $800 billion, or about 1.1 percent of the global economic output. A recent study in Health Services Research found that the additional cost of dementia to Medicare is nearly $16,000 per person over five years. About 14 percent of people in the United States over the age of 71 have some form of dementia. Alzheimer’s disease is the leading cause, afflicting 5.7 million people.
Exercise won’t reduce these numbers to zero, but it could lower them. But why would exercising the body help the mind? There are several potential pathways.
One, suggested by a nearly 10-year study of almost 500 people over 79, is that physical activity is a gateway for social and cognitive engagement. The study found that participants who were more physically active also had more social contact that engaged their brains.
In other words, physical activity brings us in closer proximity to others, with whom we then interact socially — think running clubs, adult soccer leagues, basketball pickup games or doubles tennis. And the social part, not just the physical one, may help keep our minds active.
But the physical aspect of exercise may help, too, by reducing the likelihood of vascular dementia — a common form of dementia caused by an inadequate supply of blood to the brain. Physical activity can promote the development of new blood vessels in the brain, and increase blood flow to it. This can help rid the brain of harmful metabolic waste and provide new blood flow pathways that can be alternate routes if others become blocked.
Exercise also reduces the risks of developing hypertension or Type 2 diabetes, or can help reduce their severity. Both ailments are associated with dementia. Likewise, exercise can help treat and prevent depression and reduce the prevalence of poor sleep — further risk factors for dementia.
The W.H.O. also found evidence linking a reduced risk of cognitive decline to a healthy diet and moderation in alcohol use. Supplements like vitamin E have not been found to be useful.
“A lot of this boils down to common sense,” said Mary Sano, director of research at the James J. Peters V.A. Medical Center in the Bronx and a professor of psychiatry and director of Alzheimer’s disease research at the Mount Sinai School of Medicine. “Keep physically and socially active, eat sensibly, don’t smoke and don’t drink to excess, and treat your treatable conditions.”
This approach yields many physical benefits as well. She also advises to “protect your head, which means wear seatbelts and helmets and use sturdy ladders because falls which occur frequently as we get older can be devastating to the brain.”
So, whether for your body or your mind, put down the phone and go for a walk.
