- Physical activity can help reduce the chances of cardiovascular disease by affecting stress responses in the brain, according to a new study.
- The researchers found that those who met the recommended levels of physical activity had a 23% lower risk of heart disease.
- People with depression saw a much larger benefit from physical activity.
- Experts say that the relationship between depression and heart disease can work in both directions, with heart disease developing from behaviors associated with depression or anxiety-related conditions.
Results from a new study show that physical activity’s effects on stress — and related mood conditions — can protect against cardiovascular disease (CVD).
The study, published in the Journal of the American College of Cardiology and led by researchers at Massachusetts General Hospital, examined the medical records from the Mass General Brigham Biobank of more than 50,000 people who completed a survey about physical activity.
A smaller subset of 774 study participants also had brain imaging tests to help measure stress-related brain activity.
After a 10-year median follow-up, the researchers found that 12.9% of participants developed CVD. Those who achieved recommended levels of physical exercise had a 23% lower risk of developing CVD compared to those who did not.
The researchers found that there was an inverse relationship between physical activity and stress-related brain activity: higher levels of exercise resulted in lower levels of stress-related brain activity. People with stress-related brain conditions like depression saw a much larger benefit from physical activity.
According to Dr. Ahmed Tawakol, MD, one of the researchers and a cardiologist in the Cardiovascular Imaging Research Center at Massachusetts General Hospital, exercise was “roughly twice as effective in lowering cardiovascular disease risk among those with depression.”
According to the World Health Organization, cardiovascular disease is the leading cause of death worldwide, with 17.9 million peopleTrusted Source estimated to have died of it in 2019; 85% of those deaths were from stroke or heart attack. And more than 75% of those deaths were in low- and middle-income countries.
Depression affects approximately 280 million peopleTrusted Source worldwide, according to the WHO. Unsurprisingly, depression can lead to CVD as a result of many associated behaviors, like an unhealthy relationship with alcohol, sugar, or processed foods.
Cheng-Han Chen, MD, board certified interventional cardiologist and medical director of the Structural Heart Program at MemorialCare Saddleback Medical Center in Laguna Hills, CA, who was not involved in the study, told Medical News Today that the relationship between CVD and depression is symbiotic. He said there are a number of other stress-related conditions that can provide a breeding ground of sorts for CVD.
“There is a close relationship between depression and cardiovascular disease, a relationship that runs both ways. About a quarterTrusted Source of people with cardiovascular disease experience depression, and many people with depression develop heart disease,” Chen said.
“Besides depression, other mental health disorders associated with cardiovascular disease include anxiety and PTSD. People with depression can experience increased blood pressure and physiological stress that are risk factors for heart disease. In addition, they may be more prone to adopt lifestyle changes, such as smoking and physical inactivity, that can further increase their risk of developing cardiovascular disease,” he told MNT.
Dr. David Merrill, MD, PhD, geriatric psychiatrist and director of the Pacific Neuroscience Institute’s Pacific Brain Health Center at Providence Saint John’s Health Center in Santa Monica, CA, who was not involved in the study, told Medical News Today that stress-related brain activity can lead to a number of issues elsewhere in the body, many of which are associated with depression.
He highlighted the bidirectional relationship between depression and heart disease.
“The relationship is bidirectional, with depression leading to higher rates of CVD. Anxiety similarly results in higher heart rate and blood pressure, along with elevation of cortisol, all of which increases risk of CVD. Both depression and anxiety lead to unhealthy pro-inflammatory behaviors like smoking and being sedentary. In contrast, exercise is anti-inflammatory, which is cardioprotective,” Merrill said.
Many medications for depression work by increasing neurotransmitters in the brain that can affect behavior and mood. Selective serotonin reuptake inhibitors (SSRIs) like Lexapro or Prozac are commonly prescribed for depression, and serotonin-norepinephrine reuptake inhibitors (SNRIs) like Cymbalta or Pristiq can be used to treat other anxiety-related disorders.
But 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.
Chen said that the effects of exercise can be seen chemically in the brain, but that the physical effects on the body are important to reducing the development of CVD.
“We believe that exercise changes brain chemistry to promote growth factor proteins that form new connections in the brain, particularly in the hippocampus, that improve people’s mood. Of course, exercise provides significant other benefits to underlying body physiology that can decrease someone’s changes of developing heart disease.”
— Cheng-Han Chen, MD
“It is possible that the reduction in stress-related brain activity in people with higher levels of physical activity is mediated by endorphins generated through higher-intensity exercise,” Chen explained.
Dr. Merrill added that “it turns out that exercise is at least in part good for the heart because of its effect on the brain.”
“Unlike serotonergic antidepressants, physical activity increases activity in the prefrontal cortex, which improves mood. More activity in the prefrontal cortex in turn reduces stress-related overactivation of the autonomic nervous. Exercise also increases Brain Derived Neurotrophic Factor, which improves mood through alterations in brain plasticity,” Merrill said.
