The risk of heart disease and stroke and high blood pressure, or hypertension, are intimately connected. The higher your blood pressure range, the higher your risk of heart disease, specifically of heart attack
Hypertension is common. In most countries 15 to 25% of the adult population have mildly elevated blood pressure on random screening. If blood pressure is lowered using drugs or exercise then the risk of stroke and heart attack is significantly reduced, although the risk of death from heart attack is not lowered as much as might be expected. This is possibly due to the side effects of anti-hypertensive drugs.
One environmental factor which has had a great deal of attention, particularly in the lay press, is salt intake. Currently it is thought that salt intake only plays a part in some people who are particularly sensitive to salt. These individuals make up about 60% of those with high blood pressure, and should respond with a fall in blood pressure if they limit their salt intake.
There are also certain factors which will modify the course of the disease if it is left untreated. These are age, ethnicity, gender, smoking, serum cholesterol, glucose intolerance and weight. For example, the younger you are when hypertension is diagnosed, the greater your reduction in life expectancy if your high blood pressure is left untreated.
What does high blood pressure do to your body?
Untreated hypertension affects many organs. In order to compensate for the increased pressure against which it has to work, the left ventricle of the heart increases in size by increasing the thickness of its wall. This will ultimately lead to congestive heart failure. Along with this there is increased atherosclerosis leading to ischaemic heart disease. Most deaths due to hypertension result from heart attacks or cardiac failure.
The nervous system is affected in many ways. The vessels of the retina provide an excellent way of seeing the effects of hypertension on the blood vessels directly. They are examined regularly in a hypertensive patient to get some measure of the effects of treatment. Atherosclerosis of these vessels can lead to problems with vision and even blindness in poorly controlled or undiagnosed hypertension.
