This Is Your Brain on Physical Activity

Regular physical activity is powerful. It reduces the risk of cardiovascular disease, type 2 diabetes and some cancers. It improves mental health and increases the likelihood that people will live longer and more independent lives.

Elisa Torres
Elisa Torres

The benefits of physical activity are so wide-ranging that Elisa Torres, PhD, RN, began her research looking at its impacts on depression. Soon, her physical activity studies may provide clues about how to prevent or delay the progression of Alzheimer’s disease.

“When I was working as a family nurse practitioner, I was struck by the number of people with preventable conditions, like high blood pressure and diabetes,” says Torres, an assistant professor at the University of Wisconsin–Madison School of Nursing.

“So many medications are prescribed for conditions that could be prevented, or at least better managed, through nutrition and physical activity,” says Torres. “My research focus comes from a desire to prevent people from getting sick and to keep older adults independent for as long as possible.”

Torres studies white matter hyperintensities, areas of brain tissue damage that appear bright white in MRI or CT images. White matter hyperintensities are often seen in older adults and increase in number and severity with age, but are not a normal part of aging. They have been associated with cognitive impairment, stroke, balance problems and late-onset depression.

It was the link with late-onset depression that first led Torres to study white matter hyperintensities.

Late-onset depression, when people first experience clinical depression after age 50, “has a lot of environmental factors,” says Torres. Common triggers include “being widowed, health issues, experiencing retirement as a loss of identity, or being on a fixed income.”

Working with a psychiatrist, Torres asked three groups—people with late-onset depression, a similar group without depression, and master athletes over age 50—a series of questions to estimate their physical activity throughout their lifetime.

The lifetime total physical activity questionnaire that Torres uses “covers from kindergarten onward, looking at four different types of physical activity,” she explains. “There’s occupational, which includes how much people stand or walk at work. There’s transportation, which includes if people walk or bike or run to school or work. There’s household, which includes gardening, mowing the lawn, shoveling snow, childcare, doing dishes, laundry and home maintenance. Then there’s leisure time, which is what most people think of when they think of exercise, like taking a yoga class or running on treadmills.”

Torres found that people “who exercised more throughout their life had a lot less white matter hyperintensities as mature adults.” She also confirmed that people with late-onset depression tend to have more white matter hyperintensities in their brains.

“It’s tempting to assume that physical activity can stop or delay the progression of white matter hyperintensities,” says Torres. Her study showed that the people who exercised more had fewer white matter hyperintensities—not that exercise necessarily caused the lower levels of brain tissue damage.

Torres’ current research builds on studies linking white matter hyperintensities to dementia and others suggesting that physical activity can reduce the risk of dementia. She works with the Alzheimer’s Disease Research Center (ADRC) at the UW–Madison School of Medicine and Public Health to track the lifetime physical activity of people who are at risk for but have not developed Alzheimer’s disease.

“This is one of the few ADRCs in the country that focus on people who are at risk, but have no symptoms,” says Torres. “Because of my background in health promotion and illness prevention, my interest is trying to find a way to stop these individuals from developing Alzheimer’s or to delay its occurrence.”

Changes in the brain of people who develop Alzheimer’s can be detected 20 years or more before they experience any symptoms.

“Our thinking is that 20 years is a huge window, if it’s possible to intervene” with a physical activity program that could “either prevent people from getting Alzheimer’s or slow the progression,” she explains.

Torres is collecting information that will help determine whether certain types of physical activity, or activity at certain stages of life, effectively protects against Alzheimer’s disease.

She hopes that protective physical activity will be easy for people to work into their daily routines.

“On average, 80 percent of someone’s physical activity across their lifespan is from occupational and household physical activity,” Torres adds. “The next largest amount of time is commuting. Could we get people who aren’t into exercise classes to increase how active they are at work or around the home, or to walk more on their way into school or work?”

To be effective, health promotion must “meet people where they’re at,” says Torres. “Find out what their interests are, what they can do and what they’re willing to do. Start there. Any physical activity is better than nothing. And if you’re in your 70s, walking the dog might be enough to help you stay independent.”

–Diane Farsetta