In a healthy young adult, a normal blood pressure is about 120 / 80, although some healthy people with a normal heart and blood vessels have a blood pressure well below the average.
Exercise, excitement, anger or anxiety all make your heart beat faster and increase your blood pressure temporarily.
If your blood pressure is consistently lower or higher than the normal range, then you may be diagnosed with low or high blood pressure.
What is low blood pressure?
The term hypotension (low blood pressure) is usually used only when blood pressure has fallen to the extent that blood flow to the brain is reduced, causing dizziness and fainting.
Hypotension can occur on sudden movement such as sitting or standing abruptly (postural hypotension). It can occur as a result of nerve damage which disrupts the reflexes controlling blood pressure and as an adverse effect to some drugs. Hypotension can also occur as a result of serious burns or injuries that lead to a reduction in the blood volume and to shock.
What is high blood pressure?
High blood pressure, also known as hypertension, is when your blood pressure is constantly at a higher level than recommended. It develops when the walls of the larger arteries lose their natural elasticity and become rigid, and the smaller blood vessels become narrower. This means your heart has to work harder to pump the blood around your body.
People with high blood pressure run a higher risk of having a stroke or a heart attack. If left untreated for a long time, high blood pressure can lead to kidney failure and may even damage your sight. It can also make the heart abnormally large and less efficient, leading to heart failure.
If you have high blood pressure, reducing your blood pressure can lower your risk of having all of these problems.
Generally, the target is to have a blood pressure below 140 / 85. Your doctor will give you a target that is right for you, depending on your age and general health.
What contributes to high blood pressure?
The following factors all contribute to high blood pressure:
- excessive alcohol intake
- being overweight
- side effects of drugs
- side effects of diseases
- high salt intake
- lack of exercise
Can I do anything to reduce my high blood pressure?
There are many steps you can take to reduce your blood pressure, such as:
- watching your weight. Cut down on fatty foods and eat more vegetables, fruit, fish and lean meats, bread, potatoes, pasta and rice
- restricting your salt intake to less than 6 grams of salt a day
- avoid situations which cause stress and which will cause your blood pressure to rise
- exercising regularly (up to 30 minutes a day, 5 days a week). This will help to reduce your stress levels and can also help if you're trying to lose weight
- giving up smoking. It raises your blood pressure, narrows your arteries, and puts your heart under pressure
Healthy eating on the NHS Choices website
British Heart Foundation website