The term blood pressure is used to describe pressure in the aorta. Blood pressure is at its highest when the ventricles contract (systolic pressure). The lowest (diastolic pressure) is when the ventricles relax. Blood pressure is measured in millimetres of mercury. For the average human the normal blood pressure are 120mm Hg for systolic pressure and 80mm Hg for diastolic. .
A rise in blood pressure means the heart is overworking and this can put strain on the circulatory system. On the other hand a fall can effect the organs (e.g. kidneys). So it is very important blood pressure is kept within the normal limits. .
High blood pressure is also called hypertension. It is a condition in which the blood pressure in the arteries is abnormally high. The pumping of the heart creates blood to move along and against the walls of the blood vessels, which are flexible enough to dilate or contract and therefore keep the pressure constant. Sometimes the blood vessels may lose their flexibility, or the muscles surrounding them may force them to contract. This results in, the heart pumping more forcefully to move the same amount of blood through the narrowed vessels into the capillaries, therefore increasing the blood pressure. Over time, the high pressure can damage the arterioles in such organs as the liver, kidney, or brain and can also weaken the overworked heart. This increases the risk of death from heart failure, kidney failure, or stroke. .
There is no specific cause of high blood pressure, but there are several contributing factors. These factors include smoking, high salt intake, obesity, family history of high blood pressure, kidney disease and stress. .
Smoking is not a major factor in high blood pressure and only raises blood pressure slightly. The nicotine in cigarettes restricts blood vessels and raises the blood pressure. This is because the heart has to work harder to pump blood to all parts of the body.
