Low Blood Pressure (Hypotension)
Hypotension is low blood pressure. Your blood pushes against your arteries with each heartbeat. The pushing of the blood against the artery walls is called blood pressure. Low blood pressure is good in most cases. Sometimes, however, low blood pressure can make you feel tired or dizzy. Hypotension can be a sign of an underlying condition that should be treated.
Blood pressure is measured both when your heart beats and in the periods of rest in between. The measurement of your blood pumping through your arteries is called systolic pressure. The measurement for the periods of rest is called diastolic pressure. Blood pressure is written with the systolic number above the diastolic number. The National Institutes of Health (NIH) defines hypotension as being 90/60 or lower (NIH, 2012).
Everyone’s blood pressure drops at one time or another, often without adverse reaction. Certain conditions can cause prolonged period of hypotension that can become dangerous if left untreated. These include:
- pregnancy (due to an increase in demand for blood from both mother and the growing fetus)
- large amounts of blood loss through injury
- impaired circulation caused by heart attacks or faulty heart valves
- weakness and a state of shock that sometimes accompany dehydration
- anaphylactic shock, a severe form of allergic reaction
- infections of the bloodstream
- endocrine disorders such as diabetes, adrenal insufficiency, and thyroid disease
Medications might also cause a drop in blood pressure. Beta-blockers and nitroglycerin, used to treat heart disease, are common culprits. Diuretics, tricyclic antidepressants, and erectile dysfunction drugs can also cause hypotension.
Some people have low blood pressure for unknown reasons. This form of hypotension, called chronic asymptomatic hypotension, usually does not cause harm.
Hypotension is divided into several different classifications according to when your blood pressure drops.
Orthostatic hypotension is the drop in blood pressure that occurs when you transition from sitting or lying down to standing. It is common in people of all ages. This is what some people refer to as “seeing stars” when they get up. They are most likely experiencing a brief period of dizziness caused by orthostatic hypotension.
Postprandial hypotension is the drop of blood pressure occurring directly after eating. It is a type of orthostatic hypotension. Senior citizens, especially those with Parkinson’s disease, are more likely to develop postprandial hypotension.
Neurally mediated hypotension happens after you stand for a long time. According to the National Heart, Lung, and Blood Institute, children get this form of hypotension more often than adults (NHLBI, 2010). Emotionally upsetting events can also cause this drop in blood pressure.
Severe hypotension is related to shock. Shock occurs when your organs do not get the blood and oxygen they need to function properly. Severe hypotension can be life threatening if not treated promptly.
People with hypotension may experience unpleasant symptoms when their blood pressure drops below 90/60. Symptoms of hypotension can include:
- clammy skin
- loss of consciousness
- blurry vision
Symptoms can range in severity. Some people may be slightly uncomfortable, while others may feel quite ill. Notify your doctor if you are concerned about your symptoms and blood pressure levels.
Your doctor will treat the underlying condition that causes your hypotension. This may include medications for heart disease, diabetes, or infection.
Drink plenty of water to avoid hypotension due to dehydration.
Treat orthostatic hypotension with slow, gradual movements. Instead of standing up quickly, work your way into a sitting or standing position using small movements. You can also avoid orthostatic hypotension by not crossing your legs when you sit.
Hydration can also help treat and prevent the symptoms of neurally mediated hypotension. If you suffer from low blood pressure when standing for long periods, be sure to take a break to sit down. Reduce your stress levels to avoid emotional trauma.
Shock-induced hypotension is the most serious form of the condition. Severe hypotension must be treated immediately. Emergency personnel will give you fluids and possibly blood products to increase your blood pressure and stabilize your vital signs.
Most people can manage and prevent hypotension effectively through medication and education. Learn your triggers and try to avoid them as best you can. Take medications as directed to increase your blood pressure and to avoid potentially harmful complications.
Written by: Erica Roth
Medically reviewed by George Krucik, MD