Lung Disease From Smoking

Smoking—cigarettes, cigars, pipes, marijuana, and even electronic cigarettes, or e-cigarettes—can have a harmful effect on your entire body, but especially on your respiratory system. This includes your airways, lungs, certain blood vessels, and the muscles that power your lungs.

Cigarette smoking, for example, is responsible for nearly 90% of all lung cancer deaths and 80% of chronic obstructive pulmonary disease (COPD), which includes things like emphysema and chronic bronchitis. These can be life-threatening conditions that make it difficult to breathe.

Smoking also exacerbates (worsens) other lung disorders, such as asthma, a condition in which the lungs swell and the airways narrow, making the flow of air in and out of the body difficult.

Learn more about how smoking causes lung disease and how to recognize the signs of damage.

How Smoking Affects the Lungs

When you inhale, oxygen-rich air travels through your mouth or nose into your voice box (larynx), windpipe (trachea), and then into a series of tubes, called bronchial tubes. These bronchial tubes connect to the lungs.

Once inside the lungs, the tubes branch off into smaller offshoots, called bronchioles, and then into sacs at the end of bronchioles, called alveoli.

These sacs, of which there are hundreds of millions, are surrounded by tiny blood vessels that carry the oxygen to other parts of your body. As the oxygen leaves the alveoli, carbon dioxide—a gas created by our cells—enters and is eventually released.

Along the way, tiny hairs, called cilia, clear dirt and debris from the air as it travels through your respiratory tract so it doesn’t get stuck in the lungs and cause irritation. These same cilia help remove mucus from the lungs.

That’s how the respiratory system should work. But smoking can cause things to go awry. Cigarette smoke, for example, contains 7,000 different chemicals, some of them toxic, which bombard your lungs and bloodstream with every puff. When you smoke:

• Lung mucus production increases and thickens: Your body naturally produces mucus as a lubricant and protective barrier. Excess mucus can be hard to expel, clogging your airways. It can be a breeding ground for bacteria and other germs, too.
• Cilia get damaged: Smoking reduces the number and efficiency of your cilia. That means more dirt, dust, and other particles can enter and stay in the lungs. Mucus is harder to clear, as well.
• Alveoli get destroyed: The chemicals in cigarette smoke attack the air sacs that allow oxygen to get out to your blood and carbon monoxide to leave it. Alveoli do not regenerate, so once enough damage is done, breathing becomes—and can stay—difficult.
• Bronchial tubes get irritated and inflamed: This can lead to a long-term cough and make respiratory infections more common.

Quitting smoking can help improve lung function—and it doesn’t take a lot of time to see positive changes, including:

• In a month to one year after quitting, coughing and shortness of breath decrease. Cilia—those broomlike hairs that move mucus out of your lungs—start to repair themselves.
• Ten years after quitting, your risk of lung cancer is half that of someone still smoking. Your risk of other cancers, like mouth, throat, and bladder cancer also decreases.

Lung Disease Caused by Smoking

Smoking can cause lung damage and lead to lung diseases, including:

Lung Cancer

The toxic chemicals in cigarettes and other forms of tobacco smoke can lead to cell damage. When cells are damaged, they can mutate (or change) and eventually become cancerous. Most lung cancers start in the cells that line the bronchial tubes, bronchioles, and alveoli. 

Researchers have found that smoking a pack of cigarettes a day for a year can result in, on average, up to 150 mutations to each lung cell. With so many mutations, it’s not hard to see why smokers are 15–30 times more likely to develop and die from lung cancer than nonsmokers. 

Whether marijuana smoking increases a person's risk of lung cancer is still open for debate. Additional well-designed studies need to be conducted. However, smoking marijuana can lead to other forms of lung damage, including COPD.

Chronic Obstructive Pulmonary Disease (COPD)

The dangerous chemicals in cigarettes, other tobacco products, and marijuana can cause your airways to become chronically inflamed, thickened, and narrow, leading to COPD, a lung disease in which too much air stays trapped in your lungs.

Two common forms of COPD are chronic bronchitis and emphysema.

Chronic Bronchitis

When smoking irritates and inflames the bronchial tubes, bronchitis can occur. When the bronchitis produces a wet cough that lasts three or more months for two consecutive years, it’s labeled as chronic bronchitis. This cough is sometimes referred to as a smoker's cough.

Emphysema

Emphysema is a condition in which the tiny air sacs of the lungs (alveoli) are damaged. Cigarette smoke causes the walls between the sacs to break down. These larger sacs don’t move oxygen from air to the blood as efficiently, making it harder to breathe.

Even if you’re a smoker who doesn’t meet the medical criteria for COPD, you’re still apt to have symptoms of COPD.

Research looking at current and former smokers and nonsmokers found that 50% of the smokers had symptoms of respiratory dysfunction, even though they had performed normally on a respiratory breathing test.

They were also more likely than asymptomatic smokers to have limitations on their activity, to have greater airway-wall thickening, and to be more likely to use medications like bronchodilators to open their airways.

Asthma

While smoking doesn’t cause asthma, it can make it worse. Smoking can further irritate and inflame airways that are already swollen and narrowed from asthma, making breathing even more difficult.

Signs of Lung Disease from Smoking

Symptoms of lung disease can vary by person and by the type of disease they have. But some general signs of lung disease include:

• Difficulty breathing
• Fatigue
• Shortness of breath
• Getting out of breath with activity
• Persistent coughing
• Coughing up blood or mucus
• Pain when you breathe in or out

Summary

While smoking can harm nearly every organ in your body, it delivers a direct and toxic hit to your lungs. Smoking dramatically increases your risk of a variety of lung diseases, including lung cancer and COPD.

A Word From Verywell Health

If you smoke, the best way to stop further lung damage—and to even reverse some of the harm smoking has caused to your lungs and other parts of your body—is to quit now. Reach out to your healthcare professional for information on smoking cessation programs and to get advice about prescription and over-the-counter medications that can help you quit.