Sex kills - here's how.

Unfit people, be warned – engaging in sex (or any sudden burst of physical activity) could be fatal!

A new study examined the link between fitness, sex and death and found that people are:

•    3.5 times more likely to suffering a heart attack or sudden cardiac death while exercising, compared to when they are not. This is because the heart rhythm changes and causes the heart to stop pumping blood.

•    2.7 times more likely to have a heart attack while having sex or soon afterward, compared to when they are not.

Jessica Paulus, a researcher involved in the study, said the risk of having a heart attack is fairly high as such studies go.

But, she added, the period of increased risk is brief.

"These elevated risks are only for a short period of time (1 to 2 hours) during and after the physical or sexual activity," she said.

So basically, if you look at the chance of this happening over a year, the risk decreases.

"If you take 10,000 people, each individual session of physical or sexual activity per week can be associated with an increase of 1 to 2 cases of heart attack or sudden cardiac death per year,” she said.

So does this mean you should stop having sex?

Imagine that…

"What we really don't want to do is for the public to walk away from this and think exercise is bad," she said.

What it does suggest, however, is that individuals who (want to have sex, but) do not exercise regularly need to start any exercise programme slowly, increasing the intensity of the workout gradually over time.