Researchers in Turkey found that among healthy young adults, those who smoked showed signs of poorer blood flow to the heart - and it didn't matter if their cigarette of choice was light or regular.

Critics have long charged that cigarettes branded as "light" or "low-tar" dupe the public into thinking they carry fewer health risks, even though studies have shown light cigarettes to be as deadly as regulars.

Light cigarettes are designated as such because they deliver less nicotine and lower levels of toxic chemicals when the smoke is measured by a machine. In real life, however, studies show that smokers inhale comparable amounts of nicotine and tobacco chemicals regardless of the brand.

Still, while it's known that light cigarettes aren't "safe," their effects on the cardiovascular system aren't fully clear, according to the authors of the new study, led by Dr Hakan Gullu of the Konya Teaching and Medical Research Centre.

For their study, the researchers assessed 62 adults in their 20s, including 20 who smoked regular cigarettes, 20 who used light cigarettes and 22 who'd never smoked.

All study participants underwent non-invasive imaging to gauge their coronary flow velocity reserve (CFVR), a measure of how well blood flow speeds up to aid the heart when it's under increased demands. CFVR reflects the overall functioning of the network of small blood vessels that feed the heart.

The smokers had their CFVR measured after 12 smoking-free hours, and, on a separate day, within a half-hour of having two cigarettes.

Overall, Gullu's team found, smokers had poorer CFVR than non-smokers, and their measurements became poorer still after they'd puffed on a couple cigarettes. What's more, the drop in CFVR was virtually the same whether the cigarettes were light or regular.

"Smoking low-tar, low-nicotine cigarettes seems to have the same unfavorable effect on the coronary microvascular functions as smoking regular cigarettes," the researchers conclude.

Surveys in the US, Canada and elsewhere have shown that much of the public remains confused about the health effects of light cigarettes, and that some smokers opt for these brands because they think they carry fewer risks.

This is despite public health efforts to educate people about "the 'light and mild' deception," Gullu and his colleagues point out. "Action should be taken to prohibit misleading terminology such as 'light'," they write.