Long term effects of light smoking

  I have two main questions.
  I know that smoking is harmful and that the effects on ones body differs from person to person.  However, I would like to know your general opinion on the long term use of 2-3 cigarettes per day.  Also, is it truly the nicotine that is harmful to our body's or is it the million and one chemicals that go into every cigarette?  
  Your thoughts and feelings would be appreciated.
  Thank you.

[SA, M.D. - HVMA]

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Dear Lynn,
Smoking less is better than smoking more, but there is no amount of smoking that should be considered as safe.  That's because anyone who smokes is exposing his or her body to a variety of harmful compounds, including carcinogens and carbon monoxide, which they would not be exposed to at all if they didn't smoke.
One study which looked at the risks of maternal smoking to the fetus indicated that light smokers (defined as women who smoked fewer than 10 cigarettes per day) had as many fetal abnormalities attributable to smoking as did the heavier smokers.  
Anyone who smokes on a daily basis slowly develops tolerance to the effects of nicotine.  What this means is that as the years pass, smokers require higher and higher levels of nicotine to get the same effect from the drug as they previously got from less nicotine.  Most smokers respond to the development of tolerance by smoking a greater number of cigarettes in order to boost the nicotine level.  However, smokers who do not increase the number of cigarettes smoked are often able to crank up the nicotine level by puffing more on each cigarette, inhaling more deeply,  and holding the smoke in their lungs for longer periods of time.  In this way, some people smoking 3 cigarettes a day for years and years may be doing more damage to themselves than they think.  The negative health effects of smoking have to do with how much exposure the airways get to toxic tobacco smoke, not to the absolute number of cigarettes smoked.
Nicotine is what addicts people to toxic tobacco smoke. Pure nicotine, such as that which gets absorbed through nicotine patches, is relatively safe, although some research is underway to explore potentially hazardous effects of pure nicotine on cells in the circulatory system.  So although you are correct in stating that most of the damage caused by tobacco smoking comes from toxic chemicals other than nicotine, we are still sorting out what nicotine does to the human body in its pure form.
For a lot more information about tobacco dependence and smoking cessation, check out my Ask DrSteve web site, conveniently hyperlinked below. Good luck!
Steve Adelman, M.D. (a.k.a. DrSteve)
This information is for general medical education purposes only. Please consult your physician for diagnostic and treatment options pertaining to your specific medical condition.
Keywords: smoking, nicotine
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