Cigarette smoking damages the lungs in a variety of ways. Quitting smoking, on the other hand, results in healing within the lungs and favorable changes that decrease the risk of disease. Improvements to lung function and reversal of damage begin to take place almost immediately when you stop smoking, and these benefits continue for years -- an example of the human body's remarkable ability to heal itself. The sooner you quit, the better the chance for reversing the harmful effects of tobacco smoke on the lungs.
Airway Mucus Clearing
Tiny hairlike projections on the surface of the lungs and airways -- called cilia -- clear mucus and debris from the lungs. Cilia are damaged by tobacco smoke, rendering them unable to effectively clear particles and move mucus through the airways. Cilia begin to regain function within weeks after quitting smoking, with continued improvement for at least several months. This change typically leads to decreased coughing and fewer respiratory infections due to cleaner airways throughout the lungs.
Reduced Lung Inflammation
Smoking causes inflammation of the airway walls, leading to thickening of these walls and increased mucus production. Inflammation is a key component of smoking-related lung diseases, such as chronic obstructive pulmonary disease, or COPD. After quitting smoking, airway inflammation diminishes, improving disease symptoms and leading to fewer lung infections. Additionally, when the airways return to a normal thickness, lung function improves as well. This enables the oxygen the lungs take in from the air to be more easily be moved to other parts of the body.
Improved Lung Function
A key feature of COPD is an inability to efficiently move air in and out of the lungs. Quitting smoking allows the small airways within the lungs to become more elastic. Improved elasticity permits the lungs to hold more oxygen-rich air as it is breathed in. Emptying the lungs while exhaling is also more effective, and this allows for more efficient expulsion of carbon dioxide -- a byproduct of normal metabolism -- from the body. Improved lung function can lead to an increased capacity for exercise and physical work .
The heightened risk of lung cancer in people who smoke is due to abnormal changes in the genes of lung cells caused by the chemicals in tobacco smoke. Damage to lung cells builds up over time, and eventually can lead to a cancerous tumor. Stopping smoking gives lung cells a chance to repair already-sustained genetic damage -- and additional damage from ongoing exposure to tobacco smoke is avoided. The risk of lung cancer falls within 5 years of quitting. Ten years after quitting, lung cancer risk decreases by one-third to one-half compared to people who continue to smoke, according to the Centers for Disease Control and Prevention.
Steps to Smoking Cessation
Quitting smoking is one of the most important steps you can take to improve your health and reduce your risk of disease. If you are ready to quit, and want help or support, talk with your doctor to learn more about counseling, support groups or medications that can help you stay tobacco-free.
Reviewed by Kay Peck, MPH RD
- Centers for Disease Control and Prevention: The Health Benefits of Smoking Cessation
- European Respiratory Journal: The Impact of Smoking Cessation on Respiratory Symptoms, Lung Function, Airway Hyperresponsiveness and Inflammation
- Respirology: Reversibility of Impaired Nasal Mucociliary Clearance in Smokers Following a Smoking Cessation Programme
- How Tobacco Smoke Causes Disease: The Biology and Behavioral Basis for Smoking - Attributable Disease, A Report of the Surgeon General; U.S. Department of Health and Human Services
- Respiratory Medicine: Cigarette Smoking and Airway Wall Thickness on CT Scan in a Multi-Ethnic Cohort: The MESA Lung Study
- IARC Handbooks of Cancer Prevention: Tobacco Control: Reversal of Risk After Quitting Smoking
- National Cancer Institute: Harms of Smoking and Health Benefits of Quitting
- National Heart, Lung, and Blood Institute: How the Lungs Work