Low blood pressure, also known as hypotension, is where blood pressure in your arteries is abnormally low.
Naturally low blood pressure is unlikely to cause any symptoms and is normally nothing to worry about.
But if your blood pressure drops too low, it can restrict the amount of blood flowing to your brain and other vital organs, which can cause unsteadiness, dizziness or fainting.
See your GP if you experience any symptoms of low blood pressure and are concerned.
All adults should have their blood pressure checked at least every five years. If you haven't had yours measured or don't know what your reading is, ask your GP to check it.
Read more about the symptoms of low blood pressure.
What is low blood pressure?
The heart pumps a constant supply of blood around the body through arteries, veins and capillaries. Blood pressure is a measure of the force of the blood on the walls of the arteries as the blood flows through them.
It's measured in millimetres of mercury (mmHg) and recorded as two measurements:
- systolic pressure – the pressure when your heart beats and squeezes blood into your arteries
- diastolic pressure – the pressure when your heart rests between beats
For example, if your systolic blood pressure is 120mmHg and your diastolic blood pressure is 80mmHg, your blood pressure is 120 over 80, which is commonly written as 120/80.
Normal blood pressure is between 90/60 and 140/90. If you have a reading of 140/90 or more, you have high blood pressure (hypertension). This puts you at greater risk of developing serious health conditions, such as heart attack or stroke.
People with a blood pressure reading under 90/60 are usually regarded as having low blood pressure.
Read more about diagnosing low blood pressure.
Why do I have low blood pressure?
You can have low blood pressure for many reasons, including the time of day, your age, the temperature, any medication you may be on, an injury, and some illnesses.
Read more about the causes of low blood pressure.
Treatment and self-help
Naturally low blood pressure doesn't usually need to be treated unless it's causing symptoms such as dizziness or recurrent falls. If it's causing symptoms, your GP will look at what the cause might be in case it can be treated.
There are also various things you can do to help limit symptoms of low blood pressure, including:
- standing up gradually and avoiding standing for long periods of time
- ensuring you are well hydrated
- wearing support stockings
- adding more salt to your diet
- eating smaller meals more often
Read more about treating low blood pressure.