More About Blood Pressure

High blood pressure is a blood pressure that is 140/90 mmHg or above each time it is taken. That is, the blood pressure is 'sustained' at 140/90 mmHg or above. High blood pressure can be:

• just a high systolic pressure, for example, 170/70 mmHg.
• just a high diastolic pressure, for example, 120/104 mmHg.
• or both, for example, 170/110 mmHg.
However, it is not quite as simple as this. Depending on various factors, the level at which blood pressure is considered high enough to be treated with medication can vary from person to person.
Blood pressure of 160/100 mmHg or above This is definitely high. All people with a blood pressure that stays at this level are usually offered medication to lower it (described later).
Blood pressure of 140/90 mmHg or above but below 160/100 mmHg This is sometimes called 'mild' high blood pressure. Ideally, it should be lower than this but for many people the risk from mild high blood pressure is small, and drug treatment is not indicated. However, certain groups of people with blood pressure in this range are advised medication to lower it. These are people with:
• a high risk of developing cardiovascular diseases (see below), or
• an existing cardiovascular disease (see below), or
• diabetes, or
• damage to the heart or kidney (organ damage) due to high blood pressure.

A one-off blood pressure reading that is high does not mean that you have 'high blood pressure'. Your blood pressure varies throughout the day. It may be high for a short time if you are anxious, stressed, or have just been exercising.

You are said to have 'high blood pressure' (hypertension) if you have several blood pressure readings that are high, and which are taken on different occasions, and when you are relaxed.

Observation period

If one reading is found to be high, it is usual for your doctor or nurse to advise a time of observation. This means several blood pressure checks at intervals over time. The length of the observation period varies depending on the initial reading, and if you have other health risk factors.

For example, say a first reading was mildly high at 150/94. If you are otherwise well, then a period of several months 'observation' may be advised. A blood pressure reading may be taken every few weeks. The observation period is also a good time to change any lifestyle factors that can reduce blood pressure (see below). If the blood pressure readings remain high after an observation period then treatment with medication may be advised, depending on your risk factors