Nicotine is the drug found in tobacco, which vaporises into smoke when tobacco is burnt. Although figures vary, it is estimated that around 40% of people over 16 smoke, (45% of the male population, and 34% of the female). It is thought that a further 15-25% of 13-16 year olds smoke regularly.
Passive smoking "the inhaling of smoke from other people's cigarettes" has recently become an area of investigation. Studies have found that nicotine can be detected in the blood and urine of non-smokers working in a poorly ventilated area with smokers.
SHORT TERM EFFECTS
Cigarette smoke contains tar, nicotine, carbon monoxide and several other gases. When the smoke is inhaled, those substances are absorbed through the lungs and enter the blood stream. Nicotine is a mild stimulant which has an effect on the heart and brain. Nicotine increases pulse rate and blood pressure, suppresses appetite, lowers skin temperature and stimulates areas of the brain. However, smokers often use cigarettes to reduce stress and anxiety and claim their use has a calming effect. Smokers also claim to use cigarettes to deal with fatigue and monotony. As nicotine seems to provide both a stimulant and depressant effect, it is likely that the effect it has at any time is determined by the mood of the user, the environment and circumstances of use. Studies have suggested a bi-phasic action to nicotine in the body, with low doses having a depressant effect, and higher doses a stimulant effect.
First time smokers will probably not experience any satisfaction from smoking and will feel sick and dizzy. These symptoms pass with repeated contact.
LONG TERM EFFECTS
With repeated contact, tolerance develops rapidly, although there seems to be an upper limit (which is likely to vary from smoker to smoker), such that many users stabilize at a level and their use does not escalate past that.
The greater the level of tobacco use, the greater the risk of heart disease, blood clots, lung infections, strokes, bronchitis, circulatory problems, cancer of the lungs, throat and mouth, and ulcers. It is as a result of these risks that smoking tobacco contributes to approximately 100,000 premature deaths a year in the UK. If smoking is stopped prior to damage having occurred the lungs will clear themselves over a few weeks and normal health is restored. However, it has been estimated that every cigarette smoked takes approximately 5.5 minutes off the smoker's life.
A withdrawal syndrome exists and users giving up smoking may experience restlessness, irritability, depression, and cravings for some time after use is stopped.