Why do I sometimes cough?
Coughing is the way in which the lungs dislodge anything that blocks the air passages. Usually these are only minor blockages caused by a build-up of mucus when you have a cold or chest infection. When you cough, your vocal cords press together to seal off the air passages. At the same time your chest muscles become tense, raising the pressure in your lungs. When you release the air it rushes out, carrying the obstruction with it.
How does smoking harm the lungs?
Smoking damages the natural cleaning mechanism of the lungs, and also poisons the cells that line the lungs. Tobacco smoke paralyzes the tiny beating hairs inside the air passages of the lungs. These hairs normally clean out any material that is inhaled. Tar from the smoke accumulates inside the lungs, together with small grains of soot and chemicals that can sometimes cause cancer. These substances are absorbed into the blood and can cause damage to the heart and circulation.
Regular smokers often suffer from lung diseases such as bronchitis, which are caused by irritation of the lungs by tobacco smoke.
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