Your risk of heart attack is greater immediately following sex.
There's an old saying about sex with which I've lived my entire adult life: "It's good for what ails yah." And that motto—it turns out—is a lie, and could have gotten me killed.
Per CNN, a study conducted by the Tufts Medical Center's Institute for Clinical Research and Health Policy Studies states that your risk for heart attack is tripled after sex. Before you scream, "Jumpin' Jesus on a pogo stick" and go for an emergency libido-ectomy, keep in mind that your chances are still really small that it'll actually happen. The doctors in charge of the study said the chances merely rise from 1 in a million to 3 in a million in 50-year-olds. Woman Suffers Post-Coital Stroke
The explanation goes on that extensive exercise also increases heart attack risk, but ONLY in individuals who are not generally active. The gist, if that is still a word, is that people who are mostly sedentary are in slightly greater risk of having their tickers flicker after exercise or sex. The lesson, as always, is to exercise regularly (and ease into it), lest awesome things like eating fried chicken, sex or sports cause you to die.
And start up a good stretching routine, too. The number of men I know in their late 20s who have pulled a muscle while working away their sex moves is both astonishing and embarrassing. Furthermore, being winded after 90 seconds of doggie style is more humiliating than having a post-coital heart attack. And getting injured because you're too unathletic to perform a move you saw on Cinemax after 11 is a good way to not get called back. I would also like to note that there is no shame in getting really sweaty during sex. I happen to be ashamed of my torso, neck and calves, so I wear a turtleneck and leg warmers while copulating, and that gets things pretty slick.
In summary, start an exercise regime, do it slowly, enjoy sex and if you are going to die after sex, do your partner a solid and don't die inside of them or with them inside of you.
And if you do have a post-coital heart attack-ack-ack, let the medics know if you're on Viagra. Now please enjoy my favorite video about how you SHOULD feel after sex.