High Blood Pressure (Hypertension)

What is hypertension?

Hypertension is the medical term for high blood pressure. Blood pressure depends on how forcefully the heart pumps the blood around the body and how narrowed or relaxed your arteries are. Hypertension occurs when blood is forced through the arteries at an increased pressure.

Blood pressure is measured using two numbers- for example, 120/80. The first figure is the systolic blood pressure (the pressure in the arteries when the heart contracts and pushes the blood out into the body). The second figure is the diastolic blood pressure (the pressure in the arteries when the heart is filled with blood as it relaxes between two beats).

What causes hypertension?

In the vast majority of cases, the cause of hypertension is unknown - this is called primary or essential hypertension. 

There is an underlying cause in the remaining cases (called secondary hypertension) - for example, kidney disease, chronic alcohol abuse, hormonal disturbances and endocrine tumours.

Who is at risk of developing hypertension?

Hypertension can affect anyone but some factors increase the risk of complications:

  • Family history of hypertension
  • Obesity
  • Smoking
  • Diabetes Type 1 or Type 2
  • Kidney diseases
  • Alcohol abuse
  • Excessive salt intake
  • Lack of exercise

What are the symptoms of hypertension?

There are few symptoms of high blood pressure, and the only way you can find out if you have high blood pressure is by having it measured by your doctor.

Why should I be concerned if I have hypertension?

High blood pressure causes silent damage to the blood vessels and the heart. If untreated, this damage progresses over time and may cause the following:

  • Atherosclerosis (narrowing of the arteries)
  • Stroke
  • Thoracic aortic aneurysm - expansion of the main artery in the chest
  • Abdominal aortic aneurysm expansion of the main artery in the abdomen
  • Eye damage
  • Kidney failure
  • Heart attack
  • Heart failure

How is hypertension diagnosed?

The only way to find out whether you have high blood pressure is to have it measured - a general figure for normal blood pressure is a pressure below 140/90 mmHg. Your doctor will measure your blood pressure using a device called a sphygmomanometer.

If your blood pressure is high, your doctor may ask you to return for a repeat blood pressure measurement. If this is also high you may be referred for further tests including ambulatory (walking around) blood pressure measurement over 24-hours. This will tell your doctor whether the blood pressure rise is sustained or is a response to the stress of having your pressure measured. A high blood pressure recording caused by stress is known as 'white coat hypertension'.

Your doctor may refer you for an examination of your urine and blood to exclude kidney disease and diabetes mellitus, and you will have a fasting blood test to determine the level of your cholesterol and other fats in the blood.

You may also have an electrocardiograph (ECG) to assess the state of your coronary arteries and the size of the pumping chamber of your heart, which may enlarge to cope with the high blood pressure.

How is hypertension treated?

In some cases, risk factor modification may be all that is required. For others, your doctor will recommend a course of blood pressure lowering tablets, which may include a single tablet a day, or a combination of two or three different tablets. Even though you may only have a few symptoms of hypertension it is important that you follow the prescribed treatment because it will prevent the premature ageing of your cardiovascular system.

As with all drugs, you may experience side effects - for example, some drugs that lower blood pressure also affect your libido (sex drive). Tell your doctor if you are experiencing any discomfort, as there is a wide range of treatments available and he/she may be able to change your treatment to one better suited to you.

What can I do?

  • Have regular blood pressure tests if you have a family history of hypertension.
  • Stop smoking.
  • Eat a healthy, balanced diet - reduce your intake of salt and foods that are high in cholesterol (dairy produce, shellfish and poultry).
  • Exercise - if you are overweight reducing your weight will help to lower your blood pressure.
  • Reduce your alcohol intake.
  • Never stop taking your prescribed medicine without first consulting your doctor.

What is the outlook?

Hypertension can lead to serious complications if left untreated. However, if you follow the treatment prescribed by your doctor, these complications can often be avoided.

Visit the irishhealth.com Heart Disease clinic for more advice and information on high blood pressure.

Reviewed: September 22, 2006