Impair blood flow just as much as normal cigarettes
Experts are warning that low-tar or "light" cigarettes impair blood flow through the heart just as much as normal cigarettes.
Many smokers switch to cigarettes which have low tar and low nicotine in the belief they can reduce the risks of coronary heart disease.
But, writing in the journal Heart, experts said they have studied comprehensively for the first time the cardiovascular effects of light cigarettes.
They found that blood pressure and heart rate both increase after lighting up, irrespective of the type of cigarette smoked.
Blood flow through the arteries is also impaired in smokers of both light and normal cigarettes.
Sixty-two people in their mid-20s were studied, of whom 20 had smoked low-tar, low-nicotine cigarettes (8mg tar, 0.6mg nicotine and 9mg carbon monoxide) for at least three years. Another 20 had smoked normal cigarettes while the rest were non-smokers.
The researchers found that, in the smokers, coronary flow velocity reserve was already lower than among non-smokers but fell even further after smoking, irrespective of the type of cigarette smoked.