Exercise calms the brain: Can it help depression, heart health?

Stressed and depressed? A new study suggests that exercise can help by muting stress signals and “calming” the brain — and it reduces the risk of heart disease as it does so.

In a study of 50,359 adults, researchers at Massachusetts General Hospital and Harvard Medical School found that physical activity reduced the brain’s stress-related activity. And the cardiovascular benefits were especially strong for those with depression. The study was just published in the Journal of the American College of Cardiology.

It’s well-established that depression and heart disease can be a two-way street, the presence of one increasing the risk of the other. The opposite is also true: Reducing risk of one can reduce risk of the other, as well.

Dr. Cheng-Han Chen, medical director of the Structural Heart Program at MemorialCare Saddleback Medical Center in Laguna Hills, California, told Medical News Today that cardiovascular disease and depression have a “symbiotic” relationship. Stress-related conditions can ramp up heart disease.

“There is a close relationship between depression and cardiovascular disease, a relationship that runs both ways. About a quarter of people with cardiovascular disease experience depression, and many people with depression develop heart disease,” said Chen, who was not part of the study.

“Exercise can counter depression and stress-related brain activity in a number of ways, by affecting brain chemistry naturally: regulating appetite hormones, reducing inflammation, reducing stress, and increasing metabolism,” per that article.

How much exercise helps?

For the study, the researchers delved into medical records from the Mass General Brigham Biobank to examine surveys on physical activity. They also imaged the brains of 774 study participants to look at stress-related brain activity. At a median 10-year follow-up, they found that slightly fewer than 13% of patients developed cardiovascular disease. But those who achieved recommended levels of physical exercise had 23% less risk of developing cardiovascular disease than those who were not that physically active.

“Physical activity was roughly twice as effective in lowering cardiovascular disease risk among those with depression,” study senior author Dr. Ahmed Tawakol, investigator and cardiologist in the Cardiovascular Imaging Research Center at Mass General, said.

For those without depression, the maximum heart-health benefit of exercise peaked at about 300 minutes of moderate physical activity a week. For those who had depression, additional time added extra benefit.

Those who exercised more also had lower stress-related brain activity, driven by improved function in the prefrontal cortex, the executive function part of the brain where impulse control, decision-making and other key functions occur. Notably, per the researchers, the prefrontal cortex also “restrains” the brain’s stress centers. The reduction in stress signaling helped account for exercise’s heart benefits.

Pick your exercise and do it

The World Health Organization says heart disease is the leading cause of death worldwide and as many as 17.9 million people died in 2019 from heart-related causes, mostly stroke or heart attack.

The Mass General study didn’t show causation, but rather a relationship between exercise levels and the reduction in both stress and cardiovascular disease. Tawakol said that more studies are needed to show causation. “In the meantime, clinicians could convey to patients that physical activity may have important brain effects, which may impart greater cardiovascular benefits among individuals with stress-related syndromes such as depression,” added Tawakol, who is also an associate professor of medicine at Harvard, in a written statement.

That lifestyle changes such as taking up exercise, which are often free, have great impact on health is something people should really notice and act on, Dr. Andrew Freeman, who directs cardiovascular prevention and wellness at National Jewish Health in Denver, told CNN. He was not involved in the study.

“These are incredibly cost-effective, the magnitude of improvements are amazing — often better than any medications — and we should be putting these tools in our arsenal for ready use,” he said.

Freeman told CNN that which activity one chooses matters less than the requirement that it’s somewhat hard. You should feel breathless and not be able to speak in full sentences.

“If you don’t enjoy walking or biking or swimming or whatever it is, don’t do it. But figure out a way to get a physical activity in that you truly enjoy,” he said.

Other studies have found many benefits to exercise, including a study with similar findings on depression. In February, a study published in the journal The BMJ found that exercise is valuable when battling depression. It suggested exercise should be part of the treatment plan.

Deseret News has reported on diverse benefits from exercise that include better sleep and less insomnia, lower blood pressure, lowered risk of dementia and more.