Symptoms

Low blood pressure may or may not cause symptoms. Common symptoms include:

• light headedness or dizziness
• excessive sweating
• fainting
• a feeling of an abnormal heartbeat, called palpitations

Postural hypotension

Many symptoms get worse when the person stands. Low blood pressure can also manifest as a deep drop in blood pressure after rising or standing quickly, also known as postural hypotension, orthostatic hypotension or neurally mediated orthostatic hypotension.

Postural hypotension is considered a failure of the autonomic nervous system-the part of the nervous system that controls involuntary vital actions, such as the heartbeat, to react appropriately to sudden changes. When you stand up, some blood pools in your lower extremities. Uncorrected, this would cause your blood pressure to fall. However, normally your body compensates by sending messages to your heart to beat faster and to your blood vessels to constrict. This offsets the drop in blood pressure. If this does not happen, or happens too slowly, postural hypotension results. The incidence of both low and high blood pressure normally increases with age, due in part to normal physiologic changes. In addition, blood flow in the brain declines with age, often as a result of plaque build up in blood vessels. So the prevalence of postural hypotension also increases with age; an estimated 10 percent to 20 percent of elderly people have postural hypotension

Other symptoms of low blood pressure

• fatigue and low energy
• cold extremities
• dry skin
• constipation or diarrhoea
• heat or cold intolerance
• low basal body temperature
• inability to concentrate

Studies have suggested that low blood pressure may be associated with fatigue, weakness, and depression. There may be overlap with the "chronic fatigue syndrome", which remains poorly defined, and we do not know if it is the low pressure that is actually responsible for any of these symptoms.