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Is sex exercise? And is it hard on the heart?

JUN 2011

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At some time in his life, nearly every man gets exercised about sex. And as many men get older, they wonder if sex is a good form of exercise or if it's too strenuous for the heart. These questions may sound like locker room banter, but they are actually quite important — and they now have solid scientific answers.

Treadmill vs. mattress

To evaluate the cardiovascular effects of sexual activity, researchers monitored volunteers while they walked on a treadmill in the lab and during private sexual activity at home. In addition to 13 women, the volunteers included 19 men with an average age of 55. About three-quarters of the men were married, and nearly 70% had some form of cardiovascular disease; 53% were taking beta blockers. Despite their cardiac histories, the men reported exercising about four times a week, and they reported having sexual activity about six times a month on average.

Researchers monitored heart rate and blood pressure during standard treadmill exercise tests and during "usual" sexual activity with a familiar partner at home. All the sex acts concluded with vaginal intercourse and male orgasm.

Disappointedly perhaps, the treadmill proved more strenuous. During sex, the men raised their heart rates only 72% as high as they did on the treadmill, and the average blood pressure during sex was just 80% as high as during maximal treadmill exercise. On an intensity scale of 1 to 5, with 5 being the highest, men evaluated treadmill exercise as 4.6 and sex as 2.7. Sex was even less strenuous for women in terms of heart rate, blood pressure, and perceived intensity of exertion.

Sex as exercise

Men seem to spend more energy thinking and talking about sex than on the act itself. During sexual intercourse, a man's heart rate rarely gets above 130 beats a minute, and his systolic blood pressure (the higher number, recorded when the heart is pumping blood) nearly always stays under 170. All in all, average sexual activity ranks as mild to moderate in terms of exercise intensity. As for oxygen consumption, it comes in at about 3.5 METS (metabolic equivalents), which is about the same as doing the foxtrot, raking leaves, or playing ping pong. Sex burns about five calories a minute; that's four more than a man uses watching TV, but it's about the same as walking the course to play golf. If a man can walk up two or three flights of stairs without difficulty, he should be in shape for sex.

Sex as sex

Raking leaves may increase a man's oxygen consumption, but it probably won't get his motor running. Sex, of course, is different, and the excitement and stress might well pump out extra adrenaline. Both mental excitement and physical exercise increase adrenaline levels and can trigger heart attacks and arrhythmias, abnormalities of the heart's pumping rhythm. Can sex do the same? In theory, it can. But in practice, it's really very uncommon, at least during conventional sex with a familiar partner.

Careful studies show that fewer than one of every 100 heart attacks is related to sexual activity, and for fatal arrhythmias the rate is just one in 200. Put another way, for a healthy 50-year-old man, the risk of having a heart attack in any given hour is about one in a million; sex doubles the risk, but it's still just two in a million. For men with heart disease, the risk is 10 times higher — but even for them, the chance of suffering a heart attack during sex is just 20 in a million. Those are pretty good odds.

Sex and survival

A man's heart may swell with love, but is sex swell for his heart?

Possibly so, according to a report from the United Kingdom. Researchers evaluated 918 men who were in good general health when the study began. Each man provided information on the frequency of his sexual activity; over the next 10 years, the men who reported three or more orgasms per week enjoyed a 50% lower death rate than the men who ejaculated less often.

A report from the Massachusetts Male Aging Study agrees that sex may be protective. The subjects were men between 40 and 70 who were randomly selected residents of the Boston area. A total of 1,165 men were eligible for the study and agreed to participate. None of the men had cardiovascular disease when they enrolled in the 17-year study; 213 of the men had erectile dysfunction and were analyzed separately. Among the 952 men with intact erectile function, men who had sex once a month or less were 45% more likely to develop cardiovascular disease than the men who had sex two or more times a week. The link between sexual activity and cardiac health was not explained by conventional cardiac risk factors or a man's satisfaction with his relationships.

Although the American and British findings are heartening, they do not prove that sex itself is protective. Another explanation is that sexual activity reflects a general satisfaction with life that is good for health. And it's even more likely that the men who had sex infrequently may have been burdened by social isolation or by smoking, drinking, drug abuse, or diseases that impair libido and potency. Men who choose to discuss these studies with their partners need not dwell on these major caveats.

How about Viagra?

Until recently, human biology has provided unintentional (and perhaps unwanted) protection for men with heart disease. That's because many of the things that cause heart disease, such as smoking, diabetes, high blood pressure, and abnormal cholesterol levels, also cause erectile dysfunction. The common link is atherosclerosis, which can damage arteries in the penis as well as in the heart.

Sildenafil (Viagra), vardenafil (Levitra), and tadalafil (Cialis) have changed that. About 70% of men with erectile dysfunction (ED) respond to the ED pills well enough to enable sexual intercourse. Sex may be safe for most men with heart disease, but are ED pills a safe way to have sex?

For men with stable coronary artery disease and well-controlled hypertension, the answer is yes — with one very, very important qualification. Men who are taking nitrate medications in any form cannot use ED pills. This restriction covers all preparations of nitroglycerin, including long-acting nitrates; nitroglycerin sprays, patches, and pastes; and amyl nitrate. Fortunately, other treatments for erectile function — such as the vacuum pump, alprostadil injections, or urethral tablets — are safe for men with heart disease, even if they are using nitrates.

Safe sex

Sex is a normal part of human life. For all men, whether they have heart disease or not, the best way to keep sex safe is to stay in shape by avoiding tobacco, exercising regularly, eating a good diet, staying lean, and avoiding too much (or too little) alcohol. Needless to say, men should not initiate sexual activity if they are not feeling well, and men who experience possible cardiac symptoms during sex should interrupt the sexual activity at once.

With these simple guidelines and precautions, sex is safe for the heart — but it should be safe for the rest of the body, too. Sexually transmitted diseases pose a greater threat than sexually induced heart problems. When it comes to sex, men should use their heads as well as their hearts.