It's really unlikely that having sex will stop your heart, so you've got that going for you

Cardiac arrest — when your heart suddenly stops pumping — is a killer in the U.S., but at least it probably won't happen during sex.

Scientists at the Cedars-Sinai Heart Institute analyzed over 4,500 sudden cardiac events that took place between 2002 and 2015 in Portland, Oregon, as part of the long-term Oregon Sudden Unexpected Death Study. Their results, published in the Journal of the American College of Cardiology, show that less than one percent of these cardiac arrest cases, 34 in total, were related to sex, occurring either during sex or within an hour afterwards.

As one might expect, these sexually-triggered heart incidents occurred mostly in men with an average age of 60 who had known heart problems, although one patient was 34. Only two of the cardiac arrest victims were women.

This should temper some of the concerns people with heart disease might have about this heart-pumping cardiovascular activity.

"People will ask their doctors if sex increases their risk of sudden death, and we’ve never had the answer before because there never was a study,” said Sumeet Chugh, the study’s lead author and associate director of the Heart Institute for Genomic Cardiology at Cedars-Sinai, in a statement.

“Over the years, we’ve had a fair bit of data on physical activity and how it’s related to sudden cardiac arrest, but no one had looked specifically at sexual activity. The risk is very small.”

For heart patients, the question of having sex "needed to be answered," Michael J. Ackerman, a genomics and cardiovascular researcher at the Mayo Clinic who was not involved in the study, told CNN.

"I think it's important to healthy relationships to have this anxiety lifted," Ackerman said.

Although the risk for for heart-stopping sex is small, cardiac arrest still unexpectedly kills around 300,000 people in the U.S. each year.

Cardiac arrest is different than a heart attack, which is an even greater threat, killing 735,000 Americans every year. During cardiac arrest, the heart stops when the organ's electrical system malfunctions. These are often caused by heart arrhythmias like ventricular fibrillation — so common that you've probably seen defibrilliators (AEDs) at work or in public places. Defibrilliators are intended to shock a malfunctioning heart back to its normal pumping function.

Heart attacks, however, happen when something like a glob of accumulated fat blocks the blood flow to someone's heart, depriving the heart of blood and causing part of the heart muscle to die.