The connection between exercise and brain health

"As of now, there’s no cure for Alzheimer’s disease, so a lot of the research is looking at different lifestyle factors that can play a role in slowing progression of the disease or preventing it all together," said Ryan Dougherty, a UW Health graduate student and researcher in the Wisconsin Alzheimer’s Disease Research Center. "There’s a lot of promising research that shows physical activity and exercise are associated with a healthier brain and higher cognitive functioning."

In fact, one recent study examined all the modifiable risk factors for Alzheimer’s, including smoking, obesity, diabetes and physical inactivity, and "it suggested that physical inactivity was the No. 1 modifiable risk factor," Dougherty said.

To better understand the impact of exercise on the aging brain, UW Health is participating in large, randomized national study that will test whether exercise can slow memory loss progression and symptoms in adults 65 and older who already have mild memory problems.

"This study is going to be the largest exercise trial ever tested in older adults who are experiencing mild memory loss," Dougherty said. "We’re really trying to answer the question definitively, 'Does exercise change the brain?' "

Past research from the Wisconsin Alzheimer’s Disease Research Center and the Wisconsin Registry for Alzheimer’s Prevention (WRAP) — the longest ongoing study of its kind looking at adult children of Alzheimer’s patients — points to the protective potential of exercise. Individuals who reported more physical activity on a questionnaire showed fewer negative changes in the brain, including brain atrophy and decreases in glucose metabolism.

"Those who live more active lifestyles have less Alzheimer’s-related pathology in their brains than those who are less active," Dougherty said.

But it may not be enough to simply keep moving — research from the Wisconsin Alzheimer’s Disease Research Center has found that people who spend more time participating in moderate intensity physical activity have a healthier level of brain glucose metabolism, which Dougherty describes as "fuel for the brain." These results were not found with light intensity physical activity.

It appears that physical fitness can also make a difference. Certain regions of the brain typically get smaller through the normal aging process, but individuals who were more physically fit (as determined by an exercise test of their aerobic capacity) had greater brain volume in areas related to memory. The higher the fitness level, the healthier the brain appeared. "In order to see an improvement in fitness levels, individuals need to exercise at a moderate to vigorous intensity," Dougherty said.

So how does exercise change the brain? Researchers have only theories for now, but they think it could be because exercise increases blood flow to the brain to help remove toxins, or releases hormones that help create new brain cells, Dougherty said. Research has also shown that exercise can improve cognition in healthy individuals as well as those at risk for Alzheimer’s and dementia.

Tips for a brain-boosting workout

Dougherty shares these tips for a brain-boosting workout:

• Don’t wait. Studies have found positive brain changes as soon as six months after participants start working out. “It’s never too late to start exercising,” Dougherty said. “Start with sitting less. Every hour try to stand up and move. You don’t have to go to the gym; you can do activities you enjoy, whether it’s gardening, swimming, yoga, dancing or walking with a partner.”

• Make it regular. “A lot of the research we’ve conducted has shown around 150 minutes a week of moderate to vigorous activity is beneficial, so we suggest 30 minutes of physical activity five days a week,” he said.

• Step it up. While there’s not enough research to know whether vigorous exercise has an edge over moderate exercise in terms of brain health, it’s clear that moderate exercise is worth striving for. “Moderate exercise appears to be more beneficial than light,” he said. “Moderate means exercise that makes you breathe hard. If you’re on a walk and can sing, that would be light exercise. If you can talk but can’t sing, that’s moderate. With vigorous exercise, you can only get a few words out."

• Improve your other daily habits. Exercise isn’t the only way to protect your memory. “It’s important to stay cognitively active and physically active,” Dougherty said. “Do crossroad puzzles, read books. Eat well and limit fried food. Sleep appears to be a very good modifiable risk factor as well.”