A German study has found no evidence that sex can trigger a heart attack, even in people who have already suffered one.

For those who want to grow old disgracefully, it could be good news.

A study has found no evidence that sex can trigger a heart attack, even in patients who have had one already.

Scientists rated sexual intercourse as "moderate" activity, equivalent to climbing two staircases or taking a brisk walk.

The researchers compared sexual activity and rates of fatal heart attack, stroke and death from heart disease in a group of 536 heart patients aged 30 to 70.

Participants were asked about their levels of sexual activity in the 12 months before a heart attack.

Over a period of 10 years, no correlation was seen between having sex and adverse cardiovascular events.

"Based on our data, it seems very unlikely that sexual activity is a relevant trigger of heart attack," Professor Dietrich Rothenbacher, from the University of Ulm in Germany, said.

"Less than half of men and less than a third of women are getting information about sexual activity after heart attack from their doctors.

"It is important to reassure patients that they need not be worried and should resume their usual sexual activity."

Of those taking part in the study, more than half (55 per cent) reported having sex one or more times a week. Just over a quarter had sex less than once a week, while 4.7 per cent had sex less than once a month.

A total of 14.9 per cent of patients said they had not had sex at all in the 12 months before their heart attack.

The findings are published in the Journal of the American College of Cardiology.