Orthostatic hypotension is low blood pressure that results from sudden changes in posture. It is most frequently seen when a person moves from a sitting or lying down position to standing, and results from the blood rushing to the legs and lower regions of the body.
Orthostatic hypotension is considered to be a drop in the blood pressure of either 20mmHg for the systolic pressure, or 10mmHg for the diastolic pressure. It can cause a wide range of symptoms, ranging from a feeling of dizziness and light-headedness to blurred vision, headache, seizures and a type of fainting known as vasovagal syncope. The symptoms of orthostatic hypotension will usually subside quickly and are not normally considered to be dangerous, because the body immediately responds by raising the blood pressure back to its original levels. Cases of hypotension, including those resulting from orthostatic hypotension, can actually have a wide variety of causes. Some chronic diseases, such as diabetes and many degenerative neurological conditions, can lead to the same symptoms.
In some cases, when a person has iron-deficiency anaemia or has been confined to bed for a long period of time, the volume of blood in the body may actually decrease. This leads to a condition known as hypovolemia, and it can also produce the symptoms of orthostatic hypotension. Blood loss may have the same result.
In the vast majority of cases, the symptoms that develop will be relieved almost immediately by sitting down. However, in some people, they will occur almost every time the person tries to stand and this means that it is a case of orthostatic intolerance. This occurs because the body needs to work harder to maintain blood flow when standing, and in some cases, it is simply unable to do this. Orthostatic intolerance may result from abnormalities in the cardiovascular system or the nervous system.
Mild cases of orthostatic hypotension do not usually require treatment. However, it would be advisable to take some simple precautions in order to reduce the chances of it occurring. Moving more slowly when you stand up will mean that the blood does not immediately rush to your feet, and drinking more fluids will help to maintain the blood pressure. This will minimise your chances of experiencing orthostatic hypotension.