It shows men who indulge in regular lovemaking are up to 45 per cent less likely to develop life-threatening heart conditions than men who have sex once a month or less.
The study, of over 1,000 men, shows sex appears to have a protective effect on the male heart but did not examine whether women benefit too.
Every year, around 270,000 people in Britain suffer a heart attack, and coronary disease remains Britains biggest killer.
Although sex has long been regarded as good for physical and mental health, there has been little scientific evidence to show the full benefits that frequent intercourse can have on major illnesses such as heart disease.
In the latest study, scientists at the New England Research Institute in Massachusetts, tracked the sexual activity of men aged between 40 and 70 who were taking part in a long-term project called the Massachusetts Male Ageing Study, which began back in 1987.
At regular points over a 16-year period, each man was quizzed on how often they had sex and then checked for signs of heart disease.
Researchers took into account other risk factors, such as their age, weight, blood pressure and cholesterol levels.
The results, published in the American Journal of Cardiology, showed men who made love at least twice a week were much less likely to have heart disease than those whose sexual encounters were limited to once a month or less.
In a report on their findings, researchers said the benefits of sex could be due to both the physical and emotional effects on the body.
Men with the desire for frequent sexual activity and who are able to engage in it are likely to be healthier.
But sex in some forms has a physical activity component that might directly serve to protect cardiovascular health.
Also, men who have frequent sex might be more likely to be in a supportive intimate relationship and this might improve health through stress reduction and social support.
An earlier study at the National Cancer Institute in the US showed men who ejaculated through sex or masturbation at least five times a week were much less likely to get prostate cancer.
And sex once or twice a week in winter can boost the immune system and reduce the chances of catching colds and flu, according to researchers at Wilkes University, Pennsylvania.
They found it boosted levels of immunoglobulin A or IGA which binds to organisms that invade the body and then activates the immune system to destroy them.
Regular sex can even boost a woman’s sense of smell by triggering the release of a hormone called prolactin, according to scientists at Calgary University in Canada.
This may be a mechanism to help mums bond with their new babies.