How Stress Hurts Your Heart

We know it’s a killer, but here’s why

You’re no doubt already familiar with the ways stress can ruin your mental health, career and relationships, but how does it manage to kick the crap out of your heart muscles, too? “Researchers aren’t 100 percent certain yet exactly about that answer,” says Dr. Jennifer Sumner, a clinical psychologist and instructor in medical sciences at Columbia University Medical Center. “But what a lot of the evidence suggests is that it’s the cumulative effect of repeatedly being stressed that ultimately leads to these negative outcomes.”

Here’s how experts understand it:

Constant Stress Is Wearing Out Your Heart

It’s chronic stress (continuous, ongoing pressure) rather than acute stress (the more immediate, one-off reaction to an overwhelming situation) that has the worst long-term consequences. “It can lead to your cardiovascular system not being as responsive,” Sumner says. This, in turn, leads to a range of problems, such as inflammation, reduced elasticity in your blood vessels, hardening of the arteries and blood clots. This unresponsiveness, Sumner says, happens because the parasympathetic nervous system — the system that’s supposed to calm your heart down after a moment of extreme stress (say when you’ve encountered a bear or narrowly avoided a car crash) — “doesn’t kick in as much [with prolonged stress], so basically it doesn’t get to put the brakes on your cardiovascular reactivity.”

What this all boils down to is that repeated stress has the effect of, well, stressing out your heart. “The muscles of the heart can get damaged through basically overworking,” says Dr. Friedemann Schaub, author of The Fear and Anxiety Solution. “When you have a lot of high blood pressure, the heart works harder. And when it works harder, at some point, it develops almost a fatigue that’s called cardiomyopathy.”

“The initial damage is done by acute stress hormones like epinephrine [better known as adrenaline] and norepinephrine, which affect the inner layer of the blood vessels — the endothelium — by being toxic to them,” Dr. Annika Sorensen, a health and stress strategist based in Sweden, writes via email. “The now-damaged cells are then more susceptible to damage from substances in the blood, like cholesterol. Eventually, this makes the vessels get more clogged on the inside by so-called plaque, and blood flow is impaired. Worse, cortisol — another hormone produced by stress — is toxic to these damaged cells, so the whole thing becomes a vicious circle.”

Sudden Stress Can Kill You, Too (But It’s Less Likely)

That said, acute stress also has its dangers. In rare cases, it can cause something called broken heart syndrome (more specifically, takotsubo cardiomyopathy), which is, for all intents and purposes, a heart attack. According to Sumner, it’s caused by a “weakening of the heart as a result of a severe emotional or physical stress,” such as when someone close to you dies unexpectedly, or a disaster like an earthquake or hurricane occurs. “That’s an example of how your heart can almost be broken by extreme stress,” she says.

Your Coping Mechanisms Are Also Bad for Your Heart

Sometimes, it isn’t the stress that’s damaging your heart so much as the ways in which you deal with it. Smoking, drinking, binge eating — all these things are well-documented causes of heart disease. “If the stressed person is engaging in un-heart-healthy habits, that’s going to add to the already negative impact stress is having physiologically,” Sumner says. “If their go-to coping mechanism is something associated with cardiovascular disease, that’s a point of intervention where you’d want to make a change.”

But You’ve Got Time to Fix It (Probably)

Aside from making better coping choices when you’re having a rough moment, there are a few helpful preventive steps to consider as well. “One thing would be to try to kick in that parasympathetic nervous system — that rest and restore system — faster,” Sumner says. To do this, she recommends diaphragmatic breathing, which has been shown to bring on the parasympathetic nervous system, according to Sumner.

She also suggests yoga, exercise and, of course, the psychology tip du jour — mindfulness.

Most importantly, try not to stress too much about stress stressing out your heart. “I would say, aside from takotsubo cardiomyopathy, where you usually have an immediate negative cardiovascular response to an extreme stressor, the effects of stress on your heart tend to be more cumulative,” Sumner says. “It isn’t usually an immediate impact in terms of a heart attack. So the good news is that you can intervene earlier on and try to make changes that are helpful.”

In other words, yeah, stress does physically damage your heart over time. But it does it slowly enough that you’ve got time to figure out how to stop that happening—provided you put down those smokes and go for a walk instead.