A stressful, high-octane lifestyle is probably one of the worst things you can do for your heart, and cardiologists now have a better understanding of why.
In a large-scale longitudinal study, published Wednesday in the medical journal The Lancet, a team of cardiologists at Harvard University and Massachusetts General Hospital found that stress increases heart attack risk by way of an overactive amygdala in the brain.
The amygdala is the brain’s fear center. The small, almond-shaped region in the temporal lobe lights up in reaction to fear, anxiety, stress or anything else that signals a potential threat (real or perceived). A healthy amygdala can help to protect the brain against stress, while an amygdala that’s hyper-excitable as a result of chronic stress or other factors can amplify the stress response.
The new study shows, for the first time, how an overactive amygdala can cause heart attack and stroke. When stress triggers the amygdala, it activates bone marrow and inflammation of the arteries to create the conditions for a heart attack.
“Our results provide a unique insight into how stress may lead to cardiovascular disease,” Dr. Ahmed Tawakol, a Harvard cardiologist and the study’s lead author, said in a statement. “This raises the possibility that reducing stress could produce benefits that extend beyond an improved sense of psychological well-being.”
For the study, 293 people over age 30, all without heart problems, were measured for brain activity, bone marrow activity and inflammation of the arteries. The researchers followed the participants for four years, from 2005 to 2008, during which time 22 participants experienced serious cardiac events.
Participants with more active amygdalas (as determined by the initial brain scans) were more likely to have a cardiac event over the course of the study period, and were more likely to develop heart problems sooner than those with less active amygdalas.
“Eventually, chronic stress could be treated as an important risk factor for cardiovascular disease." Dr. Ahmed Tawakol
Inflammation is known to create blockages in the arteries, which can cut off blood flow to the heart, while bone marrow activity has been linked to blood clots ― another known risk factor for heart attacks.
In a small sub-study, 13 patients with a history of PTSD had their stress levels assessed by psychology, and underwent brain scans and tests of inflammation levels. Those with the highest stress levels showed the greatest amygdala activity, and also showed more signs of inflammation.
“Eventually, chronic stress could be treated as an important risk factor for cardiovascular disease, which is routinely screened for and effectively managed like other major cardiovascular disease risk factors,” Tawakol said.
When advising patients on heart attack prevention, cardiologists typically focus on things like diet, smoking, alcohol consumption and physical activity. The new findings suggest that stress management should be considered as a preventative health measure as well.
“In the past decade, more and more individuals experience psychosocial stress on a daily basis. Heavy workloads, job insecurity, or living in poverty are circumstances that can result in chronically increased stress,” Dr. Ilze Bot, a biopharmaceutical researcher at Leiden University in the Netherlands, wrote in a comment published alongside the study. “These clinical data establish a connection between stress and cardiovascular disease, thus identifying chronic stress as a true risk factor for acute cardiovascular syndromes.”
So, if you work in a high-pressure environment or find yourself frequently under stress, consider taking up meditation, yoga, tai chi or other research-backed stress busters to keep your heart healthy. There’s a good chance that if your doctor isn’t already recommending these practices, she will be after seeing the results of this study.