You have a fight with your spouse or someone else, and you’re red-hot angry. So you go for an intense run or to the gym. Healthy way to blow off steam, right?

Not so fast. The truth is, you may be putting your heart at risk. Anger spikes adrenaline, constricts blood vessels and increases heart rate and blood ­pressure—and so does intense exercise. And the combination of exercising while ­angry is enough to trigger a heart attack in some people.

Surprising new finding: In a study of 12,461 people in 52 countries who had a first heart attack, what happened in the hour before the attack mattered. Compared with controls who didn’t have heart attacks, those who did were three times more likely to have been angry/upset and to have engaged in intense exercise beforehand—specifically, in the 60 minutes preceding the attack.

A new excuse to kick back on the couch? Not at all! Regular physical exercise plays a key role in preventing cardiovascular disease, including heart attacks. Nor should you avoid exercise when you’re angry. If exercise is your go-to way to relieve stress, go ahead—just stick with your usual workout. That’s true even if your regular exercise is intense—the key is not to increase the intensity or duration more than is normal for you.

Save those fitness ambitions for when your emotions are on an even keel. In the meantime, work on ways to have fewer episodes of anger—and better manage those that you do have. You might benefit from yoga, meditation, a walk in the woods, reading—or a combination. Just remember: When you’re feeling stressed, it’s not the time to push your physical limits. ­