People who smoke their first cigarette within minutes after waking up have much higher levels of cotinine, a by-product of nicotine when processed by the body, than those who wait to smoke, regardless of the number of cigarettes smoked.
People who smoke their first cigarette within minutes after waking up have much higher levels of cotinine, a by-product of nicotine when processed by the body, than those who wait to smoke, regardless of the number of cigarettes smoked.