Of all the instances of cardiac arrest that the researchers identified, only 34 (0.7 percent) were considered "related to sexual activity", with 18 cases having occurred during sex and 15 cases immediately after.
Cardiac arrest occurs when the heart unexpectedly stops beating, due to faulty electrical signaling that affects heart rate.
The good news is that heart attacks during sex are still rare.
Researchers led by Sumeet Chugh, MD, associate director of the Cedars-Sinai Heart Institute, analyzed data from the community-based Oregon Sudden Unexpected Death Study.
Just 34 cases occurred during or within one hour of sexual intercourse.
Scientists have found that men are far more likely than women to suffer cardiac arrest during or after sex.
"The findings are reassuring", for people with heart disease concerned that sex might be risky, said senior author Sumeet Chugh, a cardiologist at Cedars-Sinai Heart Institute in Los Angeles. We believe very strongly that our audience should have an opportunity to discuss and debate events in our world, however, we have not been able to moderate the comments as well as we would like. It usually causes death, if it's not treated within minutes.
He and other researchers wanted to know how sex affected the odds of cardiac arrest, a different problem that's more often fatal. The demographic most likely to suffer SCA from sex appeared to be middle-aged, African-American males with a history of heart disease, probably already taking heart medication.
African Americans comprised 7.8 percent of the sudden cardiac arrests in the study, but nearly 19 percent of the sexual activity-related cardiac arrests.
There's one silver lining for people who have a cardiac arrest from sex - they're nearly twice as likely to survive, Chugh said. Just 12% of patients in the study survived. They have also found that in only one in three cases does the overexerted amore receive what cardiologists term "bystander CPR", but what everyone else would term "the very least a considerate lover could do".
"This highlights the importance of continued efforts to educate the public on the importance of CPR, no matter the circumstance", Chugh said.