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Doctors are well aware that many heart patients hold back from sexual activity, fearing they'll risk sudden death or a heart attack. It’s an anxiety reinforced by movies and TV like "Something's Gotta Give," "Downton Abbey" and "Mad Men".

But the chance of sex triggering a cardiac arrest in older men and women is exceedingly rare, according to the first study to examine the link between sudden death and sex.

“People will ask their doctors if sex increases their risk of sudden death, and we’ve never had the answer,” said Dr. Sumeet Chugh, the study’s senior author and a highly respected expert on sudden cardiac arrest with Cedars-Sinai Heart Institute in Los Angeles. “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.”

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Sudden cardiac arrest occurs when an electrical impulse goes awry and the heart suddenly stops beating, halting blood flow to the brain and other vital organs. Often there are no warning signs — and if not treated immediately, almost always fatal. It's the heart condition that killed rocker Tom Petty in October.

Related: The Old-School Heart Test That May Predict Cardiac Arrest

In the study published in the Journal of the American College of Cardiology, Cedars-Sinai researchers examined records on 4,557 cases of cardiac arrest in adults between 2002 and 2015 in Portland, Oregon. Patients who experienced sudden cardiac arrest linked to sexual activity had higher rates of ventricular fibrillation — a serious cardiac rhythm disturbance — and tachycardia, a higher-than-normal heart rate. The majority of cases — 94 percent — were men who had a previous history of heart diseases and survival rates were higher in the one-third of patients who received CPR.

“This highlights the importance of continued efforts to educate the public on the importance of CPR, no matter the circumstance,” Chugh said.

Surprisingly, individuals with sex-induced sudden cardiac arrest were on average five years younger, between ages 34–83, than those who suffered from a sudden cardiac arrest that was not triggered by sex.

Related: Too Many People Stop Their Lifesaving Statins

While sexual activity involves exertion, what triggers cardiac arrest may be unique and might involve medications, stimulants and alcohol use. Even in people with clinical heart disease, the risk during sex is low.

The findings are reassuring to heart patients that sex is safe most of the time and healthy eating and exercise habits lower the overall risk of turning ecstasy into agony.