Researchers have documented that so called light cigarettes are no less harmful to cardiovascular circulation that the regular kind and they believe that there should be action to prohibit misleading terminology such as 'light'. Smoking either two regular or two billed as low-tar, low-nicotine cigarettes within 15 minutes caused rapid and significant decreases in coronary flow velocity reserve.

The study was launched by assuming that cigarettes low in tar and nicotine may be kinder and gentler to the arteries of smokers. The researchers invited 40 smokers in their mid-20s and 22 healthy non-smoking controls of a similar age.

Regular cigarettes contained 12 mg of tar, 0.9 mg of nicotine, and 12 mg carbon monoxide while light cigarettes contained 8 mg of tar, 0.6 mg of nicotine, and 9 mg of carbon monoxide. The study participants underwent echocardiography, including coronary flow velocity reserve measurement. The results showed that mean coronary flow velocity reserve values were similar between the two smoker groups, and significantly lower than in the controls.

They concluded that reducing the nicotine and tar yield is not enough for a cigarette to be called less harmful. Smoking low-tar, low-nicotine cigarettes has no different effect on the coronary microvascular functions than smoking regular cigarettes.