Blood Pressure – The Silent Killer Part 2
What Causes High Blood Pressure
The exact cause of high blood pressure is unknown. There is often no single cause and it is thought to be due to a combination of many different factors. High blood pressure often runs in families. It is not due to being nervous or highly strung. Firstly, the ageing process itself can cause the blood vessels to become less elastic and flexible and more hard or rigid. This loss of elasticity in the blood vessel walls can cause the pressure of blood going through them to go up. It is not ageing per se but rather ageing of the blood vessels that causes this hardening and resultant increase in pressure. This hardening of the blood vessels is often caused by cigarette smoking and the high-saturated-fat, high-salt diet so prevalent in the Western world.
Cigarette smoking can damage the lining of the blood vessels, causing them to narrow over time. This will make the pressure of blood going through these narrow tubes go up, as the heart has to pump harder to push the blood through a narrow space.
High cholesterol and blood fat (triglycerides) levels, caused either by a high-saturated-fat diet or by genetic factors, can lead to the formation of cholesterol plaques on the inside of the blood vessels, which causes the tubes to narrow. This is a condition known as atherosclerosis.
A diet rich in salt can also cause blood pressure to go up as sodium causes fluid retention and also affects the complex hormonal pathways that regulate blood pressure.
Obesity or carrying excess weight is also associated with an increased risk of high blood pressure. A simple analogy is that, for every extra pound of fat, there is approximately an extra mile of tiny blood vessels supplying blood to that pound of fat. So suppose you are 3 stone overweight, that means every time your heart beats it has to pump blood an extra 42 miles. In that context it is easy to see how pressure goes up, as the heart has to work harder to bring oxygen to that extra fat. While this analogy is not totally accurate, it gets the message across.
Genetic factors are obviously important in the development of high blood pressure. If there is a history of high blood pressure in your family, you need to pay extra attention to your own risk of developing high blood pressure in the future.
High blood pressure is also very common in people with diabetes, as diabetes can lead to hardening of the arteries. Stress is also recognised as a potential cause of raised blood pressure. The fight or flight response is a normal reaction in the body to feeling under stress. However, if you are under chronic long-term stress, then the long-term effect of hormones like cortisol and adrenaline on the system can result in high blood pressure. More rarely, raised blood pressure can be caused by hormonal conditions like Cushing’s syndrome and other disorders of the adrenal glands.