Low blood pressure (hypotension)

Low blood pressure – sometimes referred to as hypotension – is a condition where the arterial blood pressure is abnormally low. Blood pressure is a measure of the force that your heart uses to pump blood around your body.

The heart

The heart is a muscle that is designed to pump a constant supply of blood around the body. When your heart beats, it pushes the blood around your body through blood vessels called arteries and capillaries. When your heart rests in between beats, the blood flows back to your heart through a network of veins and capillaries. 

Blood pressure 

Blood pressure is a measure of the force of the blood on the walls of the arteries as the blood flows through them. It is measured in millimetres of mercury (mmHg).

When your blood pressure is measured, two measurements are recorded during a single heartbeat. The two measurements are known as the systolic pressure and the diastolic pressure.

• systolic pressure - is the pressure when your heart beats and squeezes blood into your arteries. At this stage, the pressure in your arteries is at its highest. 
• diastolic pressure - is the pressure when your heart rests in between beats and the blood flows back to your heart through your veins. At this stage, the pressure in your arteries is at its lowest

Your blood pressure reading will be given as two numbers, with your systolic reading first, followed by your diastolic reading. If your systolic blood pressure is 120 mmHg, and your diastolic blood pressure is 80 mmHg, your blood pressure is 120 over 80, which is commonly written as 120/80.

The highs and lows

As a general guide, the ideal blood pressure for a young, healthy adult is between 90/60 and 120/80. If you have a reading of 140/90, or more, you have high blood pressure (hypertension). This puts you at greater risk of serious health conditions, such as strokes or heart attacks.

Low blood pressure is also known as hypotension. People with a reading of around 90/60, or less, are commonly regarded as having low blood pressure. Some people who have low blood pressure experience symptoms as a result of it. There may be an underlying cause that could need treatment.