Regular physical activity is linked to better heart health. Researchers have now found that exercise lowers cardiovascular disease risk in part by reducing stress-related signaling in the brain, and the cardiovascular benefit from exercise is substantially greater for those with depression.

People with stress-related conditions such as depression reap the most cardiovascular benefits from physical activity, according to the latest study published in the Journal of the American College of Cardiology by researchers at Massachusetts General Hospital.

"Physical activity was roughly twice as effective in lowering cardiovascular disease risk among those with depression. Effects on the brain's stress-related activity may explain this novel observation," said Dr. Ahmed Tawakol, senior author of the study.

The study's conclusions were drawn from the medical records of individuals in the Mass General Brigham Biobank who responded to a physical activity survey. Out of the 50,359 participants, 774 underwent brain imaging assessments and had their stress-related brain activity measured.

After an average follow-up of 10 years, 12.9% of participants developed cardiovascular disease. Researchers noted a 23% reduced risk of heart disease in those participants who met physical activity recommendations when compared to those who did not follow the recommended levels.

Lower stress-related brain activity was noted in those participants with higher levels of physical activity. The researchers observed that decreased stress-related brain activity was linked to improvements in the functioning of the prefrontal cortex, the part of the brain responsible for executive functions and known for its role in regulating stress centers.

After adjusting for various factors like lifestyle choices and coronary disease risk factors, the researchers discovered that reduced stress-related brain signaling contributed partly to the cardiovascular advantages associated with physical activity.

The team noted a significantly greater cardiovascular benefit from exercise among participants with higher stress-related brain activity, particularly those with pre-existing depression, within the total cohort.

"Surprisingly, we additionally found a greater than twofold increase in benefits of exercise among individuals who are depressed versus individuals who don't have depression or don't have a history of depression," Dr. Tawakol told CNN.

While people without depression experienced a plateauing effect in the cardiovascular disease reduction benefits after approximately 300 minutes of moderate physical activity per week, those with depression continued to derive benefits as they spent more time being physically active, Dr. Tawakol said.

"Prospective studies are needed to identify potential mediators and to prove causality. 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," Dr. Tawakol added.

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