For one thing, the biggest fear - that you'll die during intercourse - is "highly unlikely," Dr. says. "It's understandable that lots of people may think this, based on what they've read or seen on TV, but in most cases this is not a significant risk." In fact, according to a panel of six prominent cardiac rehabilitation specialists, about 80 percent of recovering heart attack patients can safely resume having sex; 20 percent should limit sex to some extent.

The reason: Despite its physical ecstasies, sexual intercourse actually requires much less energy than most people think. In one classic study, a group of middle-aged men, all ofthem married for more than 20 years and all convalescing from heart attacks, wore 24-hour Holter (electrocardiogram) monitors at home, which recorded the secrets of their hearts during ordinary activities, including sex. This study showed that the men's heart rates at orgasm averaged only about 117 beats per minute, with an average heart rate for the period 2 minutes before and 2 minutes after orgasm averaging 98 beats per minute.

Other studies have also confirmed that - at least among middle-aged people making love with their usual partner, in a familiar setting - the top heart rate rarely exceeds 120 beats per minute, and then only briefly (usually for about 10 or 20 seconds during peak excitement). It's not unlikely that you'd get your heart that excited while playing doubles tennis or even mowing the lawn. Not terribly romantic, perhaps, but comforting all the same.

Another offcited study on the subject, conducted by Japanese researchers, looked into the causes of 5,500 sudden deaths. (These were sudden deaths in the general population, not specifically in heart attack survivors.) Thirty-four of these people died during sex, including 18 from heart attacks. But here's the kicker: Thirty of them were having sex with someone other than their spouse (and that person averaged 18 years younger than their spouse). And all of those who died during intercourse had blood alcohol at or near intoxication levels. You can fill in all the other exotic details, but the general drift of this study seems clear: Monogamous sex is fairly safe, but torrid affairs, especially with younger partners, can be murder.