Information for Patients: What Causes Hypertension?

In most people with hypertension there is no single curable cause such as a blocked renal artery, and they are labeled as having essential hypertension. This means hypertension that just happens, although there are a number of factors that we know can contribute to it. The important point is that there is no single factor that causes it, but a combination of several different ones that may play different roles in different people. There is a genetic or hereditary component: if your parents both had hypertension there is an increased chance that you will develop it as well. That component may account for about half of the factors that lead to hypertension. However, it is probable that no single gene is responsible and that more likely a cluster of genes that have different individual effects when acting in concert result in hypertension. There is also a big environmental component. Hypertension is, or was, relatively uncommon in the traditional tribal societies that lived in Southern Africa and elsewhere, but when the villagers moved to the big cities and adopted a more westernized lifestyle their blood pressure tended to increase. Whether this phenomenon is because of stress or changes in diet has not been resolved, but almost certainly both are involved. The typical American lifestyle, with a diet that is high in salt and fat and low in fruits and vegetables, combined with physical inactivity, certainly contributes to high blood pressure. Even more important is obesity, which may account for at least 50 percent of cases of hypertension. The good news here is that a lot can be done to treat and prevent hypertension by attending to diet and exercise.

What Are the Symptoms of Hypertension?

Usually, there are no specific symptoms that indicate that someone has high blood pressure. But some population surveys have shown that a wide variety of common symptoms, such as sleep disturbance, emotional upsets, and dry mouth, are slightly commoner in people with higher pressures. The differences are small, however. Going red in the face, or feeling flushed, is not indicative of high blood pressure.

If you asked a hundred people what is the commonest symptom of high blood pressure, the chances are that the majority would say headache. In fact, not only do most people with high blood pressure not have headaches any more than the rest of us, but when they do, it's usually not from the blood pressure. Merely having a high level of blood pressure inside your head does not normally produce any symptoms; if you lift a heavy weight, your pressure may go up by 30 or 40 mm Hg, but you don't get a headache. What can cause headache is muscle tension. Any muscle that is tensed for long enough starts to hurt, and chronic tension in the scalp or neck muscles is a very common cause of headache.

A study conducted many years ago shed some very interesting light on the relationship between headache and high blood pressure. Out of 104 people who had high blood pressure but were unaware of it, only three volunteered that they had headaches, although another 14 admitted it when asked. But of 96 people who had been told that they had high blood pressure, 71 said they had headaches. The simplest explanation for this finding is that being told that you have high blood pressure makes you start to worry, and that this strain in turn causes the headaches.

There is a much smaller number of patients, mostly with very high pressures, in whom headaches are directly related to the height of the blood pressure. In such individuals treating the blood pressure will relieve the symptoms.

What is White Coat Hypertension?

White coat (or office) hypertension is a term used to describe people whose blood pressure is only high in a doctor's office. Many people get nervous when they go to see a doctor, and not surprisingly their blood pressure goes up. Usually this happens less when they go back a second time, but there are some people whose blood pressure continues to be high in the doctor's office but is normal outside the office. We call this phenomenon "white coat hypertension." The usual definition of white coat hypertension is a clinic or office pressure that is more than 140/90 mmHg, and a daytime blood pressure outside the office that is less than 135/85 mmHg. It is important because if the blood pressure is normal most of the time, it does not damage the heart and other organs, and a number of studies have shown that people with white coat hypertension are at low risk of heart disease and strokes.

White coat hypertension is diagnosed by 24-hour ambulatory monitoring, which involves wearing a blood pressure monitor for 24 hours, so that the blood pressure can be recorded during normal daily life. These readings give the best prediction of your risk of future problems from your blood pressure. If white coat hypertension is diagnosed, most doctors do not recommend drug treatment, but it is very important to continue to monitor the blood pressure both in the doctor's office and outside it. The latter can be done with home monitoring.

White coat hypertension affects about 20 percent of people with mild hypertension, and it is slightly commoner in women than men. It is also more common in older people, but it sometimes occurs in children. During pregnancy it may lead to unnecessary Cesarean sections. People who have it are not necessarily neurotic or anxious.

Please click below for more information on our staff and hypertension diagnosis and treatment.

• What is Hypertension?
• Treatment of Hypertension