How Exercise Boosts the Brain

Here's Exactly How Exercise Boosts The Brain

By Maggie Puniewska

Laura Baker has seen firsthand how exercise can turn people's lives around.


As a cognitive neuroscientist at Wake Forest School of Medicine, she's studied the relationship between working out and brain health, with dozens of success stories.


One 89-year-old woman had never exercised in her life, but saw improvement in her brain health after she started exercising vigorously several times a week.


“After just a few months of exercise, she had significantly less phosphorylated tau, a protein that generally increases as Alzheimer's progresses," Baker says. “She showed that exercise could be one of the things that can impact how your brain ages."


Just as working out keeps the heart, the lungs, muscles, and bones healthy, the brain also scores big benefits from exercise. Scientists are starting to understand some of the changes that happen to your body's central command center when you hit the gym.

In fact, research has found that workouts can literally change the brain. A 2013 study split up healthy adults, 57-75 years old, into two groups. One group hopped on a bike or treadmill for one hour a day, three times a week for 12 weeks. The other remained inactive.


“We found that people who exercised had more blood flow to their hippocampus, which is the region of the brain that's responsible for memory and also the region that's one of the first to be impacted by Alzheimer's," says Sandra Bond Chapman, the study's author and the founder and chief director of the Center for BrainHealth at the University of Texas at Dallas. “What's more, the people who had this increase in hippocampal blood flow ended up performing better on memory tests too."

Baker's research has also found that exercise positively influences the brain—even in people who already have mild cognitive impairment or are at greater risk for it. In a study she's completing now, which includes the 89-year-old, she found that after six months of "high-dose" exercise—working out four times a week, for 45 to 60 minutes, at 70 to 80 percent of maximum heart rate—older sedentary adults showed big improvements. They had less phosphorylated tau, performed better on assessments that tested skills like multi-tasking and attention span, and had more blood flow to a part of the brain that typically loses circulation when Alzheimer's progresses.


“What keeps me going to the gym every day is that we saw results after just six months," she says. “That gives me a lot of hope that we can really do something to change the progression of brain diseases."


Exercise could also help maintain the brain's healthy molecular balance.


Scientists at Goethe University in Frankfurt, Germany, found that healthy older adults (65 and up) who were assigned to exercise three times a week for 30 minutes had stable levels of choline in the brain after 12 weeks, while those who remained sedentary had their choline levels spike.

Choline is a vitamin-like compound that plays a critical role in the growth of healthy cells and helps them communicate.


“We know that choline levels are often higher in people with degenerative diseases like Alzheimer's and having elevated levels could be a sign of an unhealthy brain," says lead study author Silke Matura. “Our results suggest that regular aerobic exercise could maintain and protect brain function, and to our knowledge, we were the first to show the association between exercise and choline levels in the brain."


Still, it's not just about older adults. Studies have found that exercise could help keep young minds sharp too. In one study, 95 college students were divided into three groups: one did a high intensity interval training (HIIT) regimen three times a week for 20 minutes, another did HIIT as well as computer-based brain-training activities, and the last group did nothing.


At the end of six weeks, both workout groups improved their memory, particularly their hippocampal-activated memory, which helps people hone in on fine details like picking out a friend's face in a crowd. People whose physical fitness improved the most, referred to as high responders, did the best on the memory tests. These high responders also produced more brain-derived neurotrophic factor (BDNF).


“BDNF acts like a fertilizer, supporting the functioning of brain cells," says Jennifer Heisz, the study's lead author and assistant professor of kinesiology at McMaster University in Canada. “We think that because the high responders had more BDNF, that their memory improved even more, but we suspect that people need to make fitness gains in order to make the biggest improvements."


That means that workouts should be challenging enough so that BDNF gets produced but not overly strenuous, as the stress from extremely taxing exercise seems to cancel out the benefits, she adds.

While science is making big leaps in terms of understanding how exercise impacts the brain, research still has a long way to go, especially when it comes to decoding the impact of physical activity on Alzheimer's. Baker is currently conducting a study that she hopes will illuminate if exercise can improve short-term memory, which is often a challenge for Alzheimer's patients.


From memory to attention to warding off degenerative diseases, the brain-boosting benefits of working out are just another reason to keep it a regular habit.


“People are still looking for the magic pill but our habits make such a difference in our health," says Chapman. “If you want to stay sharp and age healthily, you better get and stay moving."

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