Normal blood pressure is 120/80 mm hg where 120 is the systolic pressure and 80 is the diastolic pressure. Low blood pressure is an abnormal condition where a person's blood pressure is much lower than usual, which can cause symptoms such as dizziness or lightheadedness. When the blood pressure is too low, there is inadequate blood flow to the heart, brain, and other vital organs. A blood pressure level that is borderline low for one person may be normal for another. The most important factor is how the blood pressure changes from the normal condition. Most normal blood pressures fall in the range of 90/60 mm Hg to 130/80 mm Hg, but a significant change, even as little as 20 mm Hg, can cause problems for some people.
What are the symptoms of low BP?
Symptoms of low BP may include:
Light-headedness and fainting
Temporary loss of consciousness.
What are the causes of low blood pressure?
Low blood pressure may be caused by drugs such as the following
Medications used for surgery
Treatment for high blood pressure
Other causes of low blood pressure include the following:
Changes in heart rhythm (arrhythmias)
Anaphylaxis (a life-threatening allergic response)
Shock (from severe infection, stroke, anaphylaxis, major trauma, or heart attack)
Another common type of low blood pressure is orthostatic hypotension, which results from a sudden change in body position, usually from lying down to an upright position.
How is low BP diagnosed?
Blood pressure is measured using two numbers - the systolic first (the pressure in the arteries when the heart contracts and pushes the blood round the body) and then the diastolic (the pressure in the arteries when the heart relaxes and fills with blood between two heart beats). Blood pressure is measured using an inflatable cuff. This is positioned around the upper arm. The cuff is inflated and the doctor or nurse listens to the artery just below the cuff as the air is then released. When they can hear the heart beat, they will record the systolic pressure. When the sound disappears, they will record the diastolic pressure. Sometimes an automatic blood pressure recording machine is used. Blood pressure may be measured while lying down and then while standing. Blood pressure has to be checked regularly.
How can low blood pressure be treated?
Low blood pressure may or may not require treatment. The treatment of low blood pressure is directed toward the underlying cause. Checking whether you are drinking enough and are not dehydrated may be important. If an underlying disorder, such as a heart condition is suspected then it may be advisable to go to hospital for tests and treatment. If medications are suspected of causing hypotension the doctor will probably advise a change of drug or dosage. Bed rest and assistance with daily activities are needed until the condition improves.