impaired lung function

the bottom line

While you're in your teens, your lungs are still growing, and their ability to function is supposed to increase. But this process is impaired in teenagers who smoke.

Smoking impairs your lung function in many different ways. Smoking damages your cilia, alveoli, and bronchioles. This causes contaiminated mucus to become trapped in your lungs, causes your body tissues to get less nutrients and oxygen, and causes wheezing and shortness of breath.

explanation

If you smoke, your lungs won't work as well as they should. This isn't something that will happen thirty years from now; it happens as soon as you start smoking. Scientific studies have shown that lung function in teenagers who smoke is not as good as that in nonsmokers of the same ages. Abnormalities in lung function have been detected in smokers who are as young as 14 years old and in those who have been smoking for only one year.

While you're in your teens, your lungs are still growing, and their ability to function is supposed to increase. But this process is impaired in teenagers who smoke. Smoking decreases the rate of lung growth and therefore decreases the level of maximum lung function reached in the late teens. This happens in both boys and girls, but girls seem to be particularly susceptible to smoking's effects on lung growth and function.

Your lungs have an extremely important job to do with every breath you take. In your lungs, oxygen is extracted from the air and transferred into your bloodstream, which carries it to every cell in your body. At the same time, carbon dioxide, a waste product, is removed from the bloodstream and exhaled. This crucial gas exchange takes place in little air sacs in the lungs called alveoli.

Your lungs have much more contact with the outside world than most internal organs do. Anything that's in the air -- including dirt, germs, and smoke -- can find its way into your respiratory system (the lungs and the tubes that lead to the lungs). To protect against these contaminants, your body produces mucus, which helps to trap and carry away irritating substances from the air. The mucus-contaminant mixture is moved through the respiratory system by tiny hairs called cilia that move rapidly back and forth.

One way in which smoking damages the respiratory system is by interfering with this defense mechanism. Smoking damages the cilia, making it more difficult for mucus and contaminants to move out of the body. Smoking also changes the composition of mucus, and it may cause the glands that produce mucus to become plugged and less able to do their job. As a result of all of these changes, contaminated mucus is more likely to become trapped in your lungs if you smoke.

Smoking also damages the alveoli, the tiny air sacs where gas exchange occurs. This damage makes your lungs less able to exchange oxygen and carbon dioxide. Smoking also decreases both the amount of surface in the lungs and the number of tiny blood vessels (capillaries) where gas exchange takes place. This robs both the lungs and other body tissues of the nutrients and oxygen that they need in order to be healthy and function normally.

Smoking also causes the airways (the lungs and the tubes leading to them) to overreact to harmful substances by tightening up, making breathing more difficult. This can cause wheezing and shortness of breath (the feeling that you can't get enough air).

All of these physical changes in the lungs lead to impaired lung function. Doctors have several different tests that they use to measure people's lung function. When they perform these tests on smokers, they find that the results are much poorer than those seen in nonsmokers.