Cigarette Smoking

The role of smoking in Coronary Heart Disease

Inhaling tobacco smoke causes several immediate responses within the heart and its blood vessels. Within one minute of starting to smoke, the heart rate begins to rise: it may increase by as much as 30 percent during the first 10 minutes of smoking. Smoking also raises blood pressure: blood vessels constrict which forces the heart to work harder to deliver oxygen to the rest of the body. Meanwhile, carbon monoxide in tobacco smoke exerts a negative effect on the heart by reducing the blood's ability to carry oxygen.

Smoking and arterial disease

Smoking tends to increase blood cholesterol levels. Cigarette smokers also have raised fibrinogen levels and platelet counts which make the blood more sticky. Carbon monoxide attaches itself to haemoglobin much more easily than oxygen does. This reduces the amount of oxygen available to the tissues. All these factors make smokers more at risk of developing various forms of atherosclerotic disease. As the atherosclerotic process progresses, blood flows less easily through rigid and narrowed arteries and the blood is more likely to form a thrombosis (clot). This sudden blockage of an artery may lead to a fatal heart attack, a stroke or gangrene of the leg.

Stroke

Smokers are more likely to develop a cerebral thrombosis (stroke) than non-smokers. About 11% of all stroke deaths are estimated to be smoking related, with the overall relative risk of stroke in smokers being about 1.5 times that of non-smokers. Heavy smokers (consuming 20 or more cigarettes a day) have 2-4 times greater risk of stroke than non-smokers. A recent study showed that passive smoking as well as active smoking significantly increased the risk of stroke in men and women.

The benefits of stopping smoking

Whatever age a person is, it is never too late to give up smoking. Blood is less likely to clot, and the heart can pump more blood (and therefore oxygen) around the body with less effort. Giving up smoking reduces the risk of a heart attack and is particularly important for those who have other risk factors such as high blood pressure, raised blood cholesterol levels, are overweight or diabetic. Some studies have shown that, within five years of giving up, the risk is reduced almost to that of a non-smoker. Giving up smoking after a coronary attack can halve the chance of a recurrence. Stroke risk decreases significantly in two years and is about the same as for non-smokers after five years.

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