How does smoking affect the lungs? That's not a question that many teens consider. Lung cancer from smoking seems like a distant risk for old people. You feel healthy enough, so what's the harm in smoking cigarettes? You can always quit, right?

The truth is that smoking starts to hurt your lungs from the very first puff, and even occasional smokers can suffer ill effects.

Raising the Risk of Infection
There are two ways smoking can seriously damage your lungs: by destroying the cilia and by damaging the alveoli. Cilia are tiny hairs that line the upper airways. The cilia protect against infection by constantly moving mucus out of your lungs. When the cilia become damaged, they cannot move, which allows mucus clogged with smoke and soot to gather in the lungs. This increases your risk for lung cancer, chronic cough, respiratory infections and chronic onstructive pulmondary disease (COPD).

How many cigarettes does it take to destroy the cilia? No one knows, because it's different for every person. Smoking makes you more prone to respiratory infections, including colds, flu and bronchitis, and makes it harder for you to recover.

Shortness of Breath
Alveoli are air sacs in the lungs. When the alveoli are damaged, it becomes difficult to breathe. When you breathe in, the alveoli absorb oxygen. When you breathe out, the alveoli help to get rid of carbon dioxide.

Alveoli can be compared to tiny balloons. Smoking causes the alveoli to become less elastic, which makes it difficult to absorb oxygen and remove carbon dioxide. This is what causes shortness of breath in smokers. Symptoms of your lungs not working properly include coughing, spitting up mucus, repeat chest infections and feeling out of breath when walking up a short flight of stairs. As with the cilia, there's no telling how quickly this damage will occur.

The good news is that if you quit smoking before permanent damage occurs, your lungs have the ability to repair themselves. That doesn't mean you can smoke once a week and be fine; the damage occurs as long as you keep smoking, even if it's only a cigarette or two a day.