Cardiovascular System
Inhaling tobacco smoke causes several immediate responses in the heart and its blood vessels.
Within one minute of starting to smoke, the heart rate begins to rise; increasing by as much as 30% during the first 10 minutes. Blood pressure is also raised by smoking: vessels constrict, which forces the heart to work harder to deliver oxygen to the rest of the body. These responses are caused by nicotine.
In the meantime, carbon monoxide in tobacco smoke exerts a negative effect on the heart by reducing the blood's ability to carry oxygen. Cigarette smoking, raised blood cholesterol, and high blood pressure are the most firmly established non-hereditary risk factors leading to coronary heart disease (CHD) with cigarette smoking being the most important of them.
Respiratory Tract
Smoking causes several lung diseases that can be just as dangerous as cancer. Chronic bronchitis is one, where airways produce excess mucus causing a severe cough. Emphysema is another that slowly destroys the ability to breathe.
Chronic obstructive lung disease (including bronchitis and emphysema) is a progressively disabling condition, of which smoking is the main cause. It can cause prolonged illness due to difficulty in breathing because of the obstruction or narrowing of small airways.
For oxygen to reach the blood it must move across large surfaces in the lungs. Normally, thousands of tiny sacs make up about 100 square yards of surface area. When emphysema occurs, the walls between the sacs break down and create larger but fewer sacs, significantly decreasing the amount of oxygen reaching the blood. These are essential for the exchange of oxygen in the blood: when they break down, the lung loses its elasticity and there is less surface in the lung to absorb oxygen.
The onset of the disease is gradual and breathlessness only becomes troublesome when about half the lung has been destroyed.
Eventually, the lung surface area can become so small that a person with emphysema has to spend most of the time gasping for breath, with an oxygen bottle near by or with oxygen tubes inserted into the nasal cavity. The disease is rarely reversible once established.
Cigarette smoke contains chemicals that irritate the air passages and lungs. These substances are inhaled, and the body - in an attempt to protect itself - coughs to expel them.
The cough experienced in the mornings happens for different reasons. Normally, cilia (tiny hair-like formations lining airways) beat outward and sweep harmful material out of the lungs. Cigarette smoke, however, decreases the sweeping action, so some of the poisons in the smoke remain.
During sleep, some cilia recover and begin working again. After waking up, coughing occurs because the lungs are trying to clear away the poisons that built up the previous day. Unfortunately, prolonged exposure to smoke completely destroys the cilia's ability to function. The lungs are even more exposed and susceptible than before, especially to bacteria and viruses in the air.
Skin
Skin damaged by smoke has a grey, wasted appearance. Tobacco smoking affects skin in two ways.
Firstly, smoke released into the environment has a drying effect on the skin's surface. Secondly, because smoking restricts blood vessels, it reduces the amount of blood flowing to the skin. This depletes it of oxygen and essential nutrients.
Smoking reduces the protein elastin which is necessary for suppleness. Research suggests smoking causes a reduction in the body's store of vitamin A, which provides protection against some skin-damaging agents produced by smoking.
Wrinkling around the eyes and mouth are attributed to squinting to avoid smoke in the eyes and pursing the mouth when drawing on a cigarette. This drawing on the cigarette is also thought to be the reason that some smokers develop hollow cheeks: this is particularly noticeable in under-weight smokers, giving them a gaunt appearance.
Prolonged smoking also causes discolouration of the fingers and nails on the hand used to hold cigarettes. Teeth can become stained yellow and this is a cause of halitosis (bad breath).
Weight
Smokers tend to be thinner than non-smokers. However, the effect of smoking on the endocrine glands causes smokers to store even normal amounts of body fat in an abnormal distribution.
Smokers are more likely to store it around the waist and upper torso rather than around the hips, making them more likely to have a higher waist-to-hip ratio (WHR) than non-smokers. This increased WHR is associated with a much greater risk of developing diabetes, heart disease, high blood pressure, gall bladder problems and (in women) cancer of the womb and breast. These changes can be reversed by quitting smoking.
The habit increases the metabolic rate (that at which the body burns calories) and nicotine acts as an appetite suppressant. These are thought to be reasons why, when smoking is stopped, additional weight is gained. However, the smoking-induced increase in the metabolic rate only accounts for about half the difference in weight between the average smoker and average non-smoker.
Another likely mechanism is that smoking alters the body-weight set point (weight that a person tends to return to despite attempts to gain or lose weight). Smoking appears to lower a person's normal weight, and the weight gained on stopping reflects a return to the body's natural weight set point.
03/06/2009