As they continue to smoke, their bodies learn to depend on nicotine and they smoke more and more. Smoking is often tied to certain moods, events or places. Smoking doesn't just harm a smoker's lungs, it rots them. Smoke paralyses and can completely destroy minute hairs known as cilia, which line upper airways and protect against infection. They impair the lung's ability to absorb oxygen and get rid of carbon dioxide, forcing carbon monoxide into the smokers blood.
Smoking irritates the lungs and airways narrow, encouraging phlegm and making it harder to breathe.
Research has found those who smoked had earlier signs of atherosclerosis in the aorta, the main blood vessel in the abdomen. Atherosclerosis leads to heart disease, strokes and other forms of vascular disease. Smoking damages blood vessels and cells and makes them sticky allowing cholesterol and other dangerous fatty materials to build up. It is estimated that more than 30,000 NSW female and about 25,000 male students are recent smokers. It seems that this smoking rate has somewhat stabilised since 1992.