University of Iowa Health Science Relations and
Jennifer G. Robinson, MD, MPH
Associate Professor of Epidemiology
First Published: 2000
Last Revised: September 2004
Peer Review Status: Internally Peer Reviewed

You may have quit smoking to improve your health. But don't expect to feel healthy immediately after you've smoked your last cigarette, says a University of Iowa preventive medicine specialist.

After they kick the habit, ex-smokers can experience unpleasant side effects such as irritability, insomnia and constipation, says Jennifer G. Robinson, MD, MPH, associate professor of epidemiology and preventive cardiology in the UI College of Public Health and the Carver College of Medicine.

These side effects are the body's reaction to the withdrawal of nicotine, Dr. Robinson says. Nicotine is a chemical stimulant found in tobacco. It enters the body via cigarette smoke, and causes many smokers to become physically dependent upon its stimulating effects.

"When you quit smoking, your body needs time to recover from the stimulating effects of nicotine," Dr. Robinson says. For the average ex-smoker--someone who smoked one to two packs of cigarettes a day--the unpleasant side effects last less than a week, she says.

Persons who stop smoking sometimes are surprised that their smoker's cough continues for a week or two. This results from the reactivation of cilia, tiny hairs lining the person's airways that have been paralyzed by cigarette smoke. When the cilia resume their normal mucus-clearing function after a person stops smoking, the resulting tickle sensation can trigger a cough, Dr. Robinson explains.

Constipation is another side effect frequently experienced by persons who have recently quit smoking, she says.

Some smokers may experience constipation because nicotine is no longer present to stimulate digestion. Nicotine accelerates the muscular movement of the digestive tract.

Some recent ex-smokers also may experience irritability and insomnia, as their bodies withdraw from the addicting chemical, nicotine, Dr. Robinson says.

A person may notice he or she is perspiring more frequently than usual during the first few days after the last cigarette is smoked. Perspiration is the body's way of flushing out the chemicals accumulated from smoking, she says.

"These side effects may make one question whether it's worth while to quit smoking," Dr. Robinson says. Yet even while the unpleasant and temporary side effects are occuring, the x-smoker's heart and lung functions are improving. The damaging effects of carcinogens in cigarette smoke begin to resolve immediately after quitting smoking, she adds.

Heavier smokers (more than two packs a day), may choose to use a nicotine replacement to ease symptoms after quitting, Dr. Robinson recommends. Nicotine patches or gum can be found over-the-counter in pharmacies and should be used according to package directions. Other medications to help people quit are available through your physician.