Asthma and Airway Centre

The Asthma Education Handbook

How Smoking Affects the Lungs

The lungs are sensitive to many irritants including smoke. This increases the need for more medication to keep your asthma or other breathing problems under control. Smoking gradually damages the lungs and can cause permanent damage to the airways and lung tissues by constant irritation and inflammation. Nicotine reaches the brain within seconds. Passive smoke (second-hand smoke or environmental smoke) can cause significant health hazards.

Smoking is a major risk factor for developing chronic obstructive pulmonary disease (COPD). This term is used to include chronic bronchitis and emphysema or a combination of both conditions.

Chronic bronchitis
The diagnosis of chronic bronchitis is made based on your exposure to occupational dust and history of smoking. In chronic bronchitis, the inner lining of the airways becomes inflamed or swollen, and more mucus (phlegm) is produced. When this happens the airways become narrow and the airflow is blocked with mucus making you short of breath. The symptoms of cough with mucus production for three or more months for two years in a row may be a clue that you have chronic bronchitis. Chest-xrays and breathing tests are helpful in making the diagnosis. It is important to treat chest viral or chest infections promptly and take preventive measures such as having flu and pneumonia vaccines. Quitting smoking will prevent irritation in the airways so less mucus is produced, thereby reducing airflow obstruction.
View an image of normal bronchioles that move air in and out of the lungs
View an image of airways with chronic bronchitis

Emphysema
Smoking is the most common cause of emphysema (chronic obstructive pulmonary disease, COPD) but can be caused by environmental factors such as exposure to industrial dust, pollution and in some cases genetics. It involves damage to the walls of the air sacs (alveoli) and supporting terminal or smaller airways. These changes cause air to be trapped in the air sacs. When air is trapped in the air sacs the walls of the air sacs are over stretched (like a balloon) and looses the elasticity or the ability to push air out of the lungs. This increases the effort to breathe and creates shortness of breath. Other symptoms include cough with or without mucus production, wheeze and shortness of breath usually with activities of daily living. These symptoms may be persistent or vary over time depending on the severity of emphysema. The damage caused by smoking and other irritants/chemicals are permanent. Quitting smoking is the most important thing you can do to slow down the damage to your lungs.

The diagnosis emphysema is made by assessment of your symptoms, breathing tests or other tests. Living with emphysema may require some changes in the way you normally do things. Learning to cope with breathlessness, doing breathing exercises, keeping active, eating nutritious food, managing stress and avoiding rushed activities are some helpful tips in managing emphysema and improving quality of life. Most of all, it is important to use inhaled medication correctly to help you with shortness of breath.
View an image of emphysema in the air sacs
View an image of multi-component COPD

Smoking is the major cause of lung cancer
Tobacco smoke is the most common cause of lung cancer. One in 10 heavy smokers will get lung cancer, and in most cases it is fatal. It is the leading cause of death by cancer because of its difficulty to detect. Lung cancer can spread to the liver, brain and bones.

llustration adapted from
Kimberly A. Martens

Heart disease and stroke
Arteriosclerosis (narrowing or hardening of the arteries) is a condition responsible for most heart attacks and strokes. Coronary arteries of the heart or arteries supplying the brain with oxygen eventually narrow due to plaque build up. The oxygen supply to the heart is reduced or stopped. Smoking increases the risk of developing cardiovascular disease.

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Smoke and children
hildren who are exposed to passive or secondhand smoke have a greater tendency to get lower respiratory tract infections such as bronchitis and pneumonia. There is evidence indicating that babies of smoking mothers have low birth weight, failure to thrive, decreased lung function and are more prone to ear infections. Passive smoke also increases the risk of children getting asthma or making asthma symptoms worse. Children of smokers are more likely to start smoking than those of parents who do not smoke.

Quitting smoking
Most people are aware of the risk involved from smoking, yet continue to do so in a habitual manner. They need the advice and encouragement from families, friends, co-workers and medical personnel to help them quit.

It is not difficult to understand why quitting is such a problem for long time smokers. Nicotine is one of the most addictive of drugs and it is absorbed into the bloodstream in a matter of seconds when a cigarette is smoked. In addition, many smokers derive pleasure from the handling of a cigarette - it 's a stress reliever. Over many years of smoking, the smoker learns to associate many common activities with smoking. These associations can trigger the desire for a cigarette during a quitting attempt. Don't be discouraged if you have tried to quit before without success. Most smokers who quit successfully make several quitting attempts before they succeed.

At present, there are a number of smoking cessation programs and new treatments developed to help you stop smoking. The first step is to consult your doctor who can recommend a cessation program and can assist and support you in breaking your smoking habit. Many people wonder if nicotine gum or nicotine patches can help them to quit.

Talk to your doctor or pharmacist so the appropriate choice or preference can be discussed. Remember, nicotine replacement with gum or patches can help by decreasing the craving and making quitting easier for you. Nicotine replacement is a helpful add-on that won't replace hard work and determination on your part. Set a quitting date and have a positive attitude. It may take more than several attempts to quit the habit so don't be discouraged if you have had previous failed attempts.

There are a number of organizations available that provide programs for smoking cessation and support groups. These include:

Your Local Health Unit
The Cancer Society
Heart and Stroke Foundation
Your Family doctor
For residents in Toronto, Ontario, please contact the Asthma and Airway Centre at (416) 603-5864.

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