Doctors have for long said that cycling is good for health. But,now a new study has claimed it is literally one of the biggest triggers of heart attacks.
The study,which analysed 36 pieces of research,has revealed that the “final straw” in bringing on a heart attack is spending time in traffic as a driver,cyclist or commuter,’The Lancet’ journal reported.
But of these,cyclists are in greatest danger because they are more heavily exposed to pollution and are subjecting themselves to another major heart attack trigger,exercise.
Traffic exposure was blamed for 7.4 per cent of heart attacks,followed by physical exertion with 6.2 per cent. Air pollution triggered between 5 per cent and 7 per cent of heart attacks,while drinking alcohol accounted for 5 per cent.
Other risk factors included negative emotions (3.9 per cent),anger (3.1 per cent),eating a heavy meal (2.7 per cent),positive emotions (2.4 per cent) and sexual activity (2.2 per cent).
Cocaine was to blame for 0.9 per cent of heart attacks,but this was because of limited exposure to the drug among the population.
On an individual basis,taking cocaine was shown to raise a person’s risk of having a heart attack 23-fold,according to the study,led by Dr Tim Nawrot,from Hasselt University in Belgium.
In comparison,air pollution led to a 5 per cent extra risk,but since far more people are exposed to traffic fumes and factory emissions than cocaine,air quality is a far more important population-wide threat.
Professor David Spiegelhalter,a risk expert from Cambridge University,said it was difficult to “disentangle” the risk factors in the study for certain situations,such as driving or cycling to work in heavy traffic.
“A lot of other factors are contributing to the overall risk; air pollution,stress,physical exertion,even anger which is another well-known trigger for a heart attack. It’s a complex mix,” the ‘Daily Mail’ quoted him as saying.
Judy O’Sullivan,senior cardiac nurse at the British Heart Foundation,said the benefits of exercising outdoors outweighed the risks from air pollution for most individuals,and urged people not to be put off running,walking or cycling in towns and cities.