Questions About Smoking, Tobacco, and Health

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How does tobacco smoke affect the lungs?

Damage to the lungs begins early in smokers, and cigarette smokers have a lower level of lung function than non-smokers of the same age. Lung function continues to worsen as long as the person smokes, but it may take years for the problem to become noticeable enough for lung disease to be diagnosed. Smoking causes many lung diseases that can be nearly as bad as lung cancer.

Chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a name for long-term lung disease which includes both chronic bronchitis and emphysema (discussed below). Here are some facts about COPD:

  • More than 12 million people in the United States suffer from COPD. Another 12 million may have the disease and not suspect it because they don’t know the early warning signs.
  • More women die from COPD than men.
  • Smoking is the main risk factor for COPD -- about 80-90% of COPD deaths are caused by smoking.
  • The longer and heavier a person smokes, the higher their COPD risk.
  • There’s no cure for COPD.

COPD most often starts unnoticed in young smokers, and usually gets far worse before it’s diagnosed. Noises in the chest (such as wheezing, rattling, or whistling), shortness of breath during activity, and coughing up mucus (phlegm) are some of the early signs of COPD.

Over time, COPD can make it hard to breathe even at rest. It limits activities and causes serious health problems. The late stage is one of the most miserable of all illnesses. It makes people gasp for breath and feel as if they are drowning.

Chronic bronchitis

Chronic bronchitis is a type of COPD, a disease where the airways make too much mucus, forcing the person to cough it out. It’s a common problem for smokers. The airways become inflamed (swollen) and the cough becomes chronic (long-lasting). The symptoms can get better at times, but the cough keeps coming back. Airways get blocked by scar tissue and mucus, which can lead to bad lung infections (pneumonia).

There’s no cure for chronic bronchitis, but quitting smoking can help keep symptoms under control. Quitting smoking also helps keep the damage from getting worse.


Smoking is also the major cause of emphysema, the other type of COPD, which slowly destroys a person’s ability to breathe. Oxygen gets into the blood by moving across a large surface area in the lungs. Normally, thousands of tiny sacs make up this surface. In emphysema, the walls between the sacs break down and create larger but fewer sacs. This decreases the lung surface area, which lowers the amount of oxygen reaching the blood. Over time, the lung surface area can become so small that a person with emphysema must work very hard to get enough air, even when at rest.

Signs of late emphysema may include a cough that doesn’t go away (which is often dismissed as “smoker’s cough”), shortness of breath even when lying down, feeling tired, and weight loss. People with emphysema are at risk for many other problems linked to weak lung function, including pneumonia. In later stages of the disease, patients can only breathe comfortably with the help of an oxygen tube under the nose.

Emphysema cannot be cured or reversed, but it can be treated and slowed down if the person stops smoking.

Why do smokers have “smoker’s cough?”

Tobacco smoke has many chemicals and particles that irritate the airways and lungs. When a smoker inhales these substances, the body tries to clear them by making mucus and coughing.

The early morning smoker’s cough happens for many reasons. Normally, tiny hair-like formations (called cilia) beat outward and sweep harmful material out of the lungs. But tobacco smoke slows the sweeping action, so some of the particles in the smoke stay in the lungs and mucus stays in the airways. While a smoker sleeps (and doesn’t smoke), some cilia recover and start working again. After waking up, the smoker coughs because the lungs are trying to clear away the irritants and mucus that built up from the day before.

The cilia will completely stop working after they’ve been exposed to smoke for a long time. Then the smoker’s lungs are even more exposed and prone to infection and irritation. So-called “smoker’s cough” can be an early sign of COPD (see above, “Chronic obstructive pulmonary disease” in the section “How does tobacco smoke affect the lungs?”)

If you smoke but don’t inhale, is there any danger?

Yes. Wherever smoke touches living cells, it does harm. Even smokers who don’t inhale are breathing secondhand smoke. They are at risk for lung cancer and other diseases caused by secondhand smoke.

Pipe and cigar smokers, who often don’t inhale the smoke directly from the burning tobacco, are at an increased risk for lip, mouth, tongue, and some other cancers, too. See our document Secondhand Smoke for more information.

Last Medical Review: 02/13/2014
Last Revised: 02/13/2014