An Australian study has found that sex does not increase the chances of heart attack, but cocaine lifts the risk up to 20 times, contrary to movie mythology. The study reported that 'while sex causes very little increased risk of heart attack, use of cocaine could lift the likelihood 20-folds'.

The review by University of Sydney and Harvard academics is the first to analyse triggers for heart attacks, including sexual activity, cocaine use, pollution, heavy meals, and stressful events like terrorist attacks.

Co-researcher Geoffrey Tofler, who is associated with both the universities, said that the traditional approaches to heart attack prevention like diet and exercise regimes, medication often ignored other triggers like external pressures such as sudden severe stress or physical exertion which could be a factor in up to 40 per cent of heart attacks.

"We know, for example, that the incidence of heart attacks rises sharply in the days after people are exposed to major events such as an earthquake or a September 11," he said. He added that if individuals know what the relative risks are, they would be better able to manage their own health accordingly.

Prof Tofler and Harvard colleague Dr James Muller have used their results to develop a new approach called 'Triggered Acute Risk Prevention (TARP)', which talks about measures to help avoid attack. "It would be a concern if focus on very small risks associated with the stress of daily living led to excessive caution," Prof Tofler. They will further investigate other potential stresses, including bereavement, infection and heavy physical exertion.