Having low blood pressure doesn’t necessarily mean there is a problem, but it could be the result of another illness or condition. Low blood pressure, medically known as hypotension, is when your blood pressure is below 90/60mmHg. This does not necessarily mean that there is a problem. In fact, people with low blood pressure tend to live longer than those with high, or even normal, blood pressure. When you
have your blood pressure measured, your blood pressure reading is written as two numbers. The first is when the pressure is at its highest (or systolic pressure), and the second at its lowest (or diastolic pressure). Systolic pressure: This is the highest level of your blood pressure – when your heart beats and contracts to pump blood through your arteries. Diastolic pressure: This is the lowest level of your blood pressure – when your heart relaxes between beats. Low
Blood Pressure Low blood pressure is sometimes found during a routine check-up. Most people with low blood pressure don’t have any noticeable symptoms. However, it can cause dizziness or even fainting. Sometimes low blood pressure can be the result of another illness or condition. So, if you
are having symptoms such as dizziness or fainting, it is important that you see your doctor.What is low blood pressure (hypotension)?
How is blood pressure measured?
What are the signs and symptoms of low blood pressure?
What causes low blood pressure?
If your blood pressure is unusually low, your doctor should check to make sure there is not a medical cause. Low blood pressure can sometimes be a side effect of medicines taken for high blood pressure, heart disease or depression. If this happens to you, your doctor may need to adjust the dose of the medicines you are taking, or give you a different medicine. Low blood pressure can also be caused by some over-the-counter and herbal medicines.
Want to find out more?
- Check out the NHS low blood pressure webpage
As blood is pumped by the heart around the body, the pressure with which it pushes against the walls of blood vessels changes.
When the heart is squeezing blood into the arteries, the pressure is high. When the heart is relaxed, the pressure is lower.
Your blood pressure is a measurement taken of the highest reading and the lowest reading. It is given as 2 figures — highest over lowest. Blood pressure is measured in ‘mmHg’, which refers to millimetres of mercury.
What is low blood pressure?
Low blood pressure is also known as hypotension.
Most doctors would say that you have low blood pressure if it is below 90/60 mmHg. Your doctor will refer to this as ‘90 over 60’.
Is low blood pressure a problem?
For some people, low blood pressure is a sign of good health. These are generally people who are very fit and who have a slow pulse. For other people, low blood pressure is a problem.
Often, people with low blood pressure can be expected to lead longer lives.
However, people who experience continuing symptoms of low blood pressure should see a doctor. Sudden, severe low blood pressure (shock) can be associated with serious medical conditions.
What are the signs and symptoms of low blood pressure?
The symptoms of low blood pressure may include:
- light-headedness
- dizziness
- weakness
- blurry vision
- pale, clammy skin
- fatigue
- fainting
These symptoms can occur when doing nothing. They are more likely to occur when changing position, such as standing up or when straining on the toilet.
However, often there are no symptoms and low blood pressure is often only identified as a result of a routine medical examination or during the course of an investigation for some other condition or underling illness.
Low blood pressure may be more serious in elderly people who may have an underlying illness or who may be at risk of a fall.
Check your symptoms with healthdirect’s Symptom Checker to get advice on when to seek medical attention.
What causes low blood pressure?
Apart from being very fit, people can have low blood pressure if they:
- are overheated, either from the weather, from hot baths or showers, or from wearing too many clothes
- have too little blood circulating, either from donating blood, from bleeding heavily, or from being dehydrated
- are pregnant
- are taking one of many different types of medicines
- have a lot of drugs or alcohol in the system
People can also have low blood pressure due to medical conditions, such as if they:
- are having an allergic reaction
- are seriously ill with an infection
- have certain heart conditions
- have a disorder of the nervous system or glandular (endocrine) system
- are in severe pain
- have nutritional deficiencies
There is also a particular type of low blood pressure called ‘postural hypotension’ or ‘orthostatic hypotension’. In this condition, a person’s blood pressure is normal when they are sitting or lying down, but it drops suddenly when they stand, making them feel dizzy or lightheaded. This can also occur when standing too long without moving.
Postural hypotension is fairly common, particularly in older people. It can be caused by one of the situations or conditions listed above. If it happens often, or if it causes problems, you should see your doctor about it.
When should I see a doctor?
If you think you might have symptoms of low blood pressure listed above, it’s best to see your doctor.
How is low blood pressure treated?
If there is an underlying cause for your low blood pressure, and it is giving you problems, you may need treatment for that underlying cause. But if it isn’t causing you problems, treatment won’t be needed.
Your doctor may advise you to take precautions to prevent episodes of low blood pressure, such as avoiding dehydration, hot showers or standing up too quickly.