Low blood pressure (hypotension)

Low blood pressure or hypotension refers to abnormally low pressure in the blood vessels. It should not be confused with blood pressure reading which is below the threshold for hypertension (high blood pressure); that is obviously normal and desirable and indeed a marker of good health.

Lowish blood pressure usually does not cause any problems and is nothing to be worried about. However, excessively low blood pressure may mean failure to supply enough blood to the brain and to the other vital organs, causing symptoms like dizziness, lightheadedness, fainting and collapses. However, much more frequent – and dangerous – is high blood pressure which is usually asymptomatic. Everybody should get his/her blood pressure checked at least every five years. If you don’t know your blood pressure reading, ask your GP. The gold standard in diagnostic of blood pressure is 24-hour blood pressure monitor.

What is low blood pressure?

The heart is a muscular organ that constantly pumps blood into arteries around the body to supply oxygen and nutrients. The pumping of the heart makes the blood to produce a force against the wall of blood vessels. This force is called blood pressure. Blood pressure readings are given as two figures: the first is systolic and the second is diastolic pressure. Blood pressure is measured in millimeters of mercury (mmHg).

The pressure recorded during contraction of the heart is called systolic blood pressure, while the pressure during relaxation of the heart is called diastolic blood pressure. For instance, if your systolic blood pressure is 120 mmHg and that of diastolic blood pressure is 80 mmHg, it will be denoted as 120/80 mmHg or “120 over 80 mmHg”.

Blood pressure around 110/60 mmHg to 130/80 mmHg is usually considered normal while people with readings above 140/90 mmHg are hypertensive. People with blood pressure 90 over 60 (90/60) mmHg or below are hypotensive and may get the symptoms mentioned above.

Why does it happen?

You may have low blood pressure for several reasons including time of the day, age, temperature, injury, pregnancy, some medicines or diseases, such as infection. Bleeding, low body temperature, sepsis (severe infection), heart muscle disease, vomiting, diarrhea and severe allergic reactions may lead to hypotension.

Treatment and self-help

Usually, low blood pressure does not generate any symptoms and thus needs no treatment. However, some people may present with dizziness, fainting and recurrent falls which should trigger appropriate evaluation and treatment.

You can follow several simple steps to avoid low blood pressure symptoms:

  • Stand up slowly
  • Make sure you drink enough fluids, at least 1.5 litres daily
  • Reduce alcohol and coffee consumption
  • Add more salt to your diet
  • In case of dizziness or impeding fall, quickly sit or even better lie down and lift up legs
  • See your GP and get your medication reviewed