Harvard Heart Letter

Zero exposure is the only safe bet with smoking

Help is out there for those who want to quit.

Smokers know well that the best thing they can do for themselves and the people around them is to quit. But the nicotine in cigarettes is viciously addictive. People who've been hooked on both nicotine and narcotics commonly say cigarettes are a harder habit to kick than heroin.

There is no safe level of smoke exposure. Inhaling one to four cigarettes a day carries about the same risk of heart disease as smoking a pack a day. And exposure to smoke significantly increases the risk of heart disease among nonsmoking bystanders. Evidence even suggests that the sidestream smoke from an idly burning cigarette is more toxic than the mainstream smoke inhaled by the smoker.

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