Low Blood Pressure (Hypotension)
Hypotension is low blood pressure. Your blood pushes against your arteries with each heartbeat. And the pushing of the blood against the artery walls is called blood pressure.
Low blood pressure is good in most cases. But low blood pressure can sometimes make you feel tired or dizzy. In those cases, hypotension can be a sign of an underlying condition that should be treated.
Blood pressure is measured when your heart beats, and in the periods of rest between heartbeats. The measurement of your blood pumping through your arteries when the ventricles of the heart squeeze is called systolic pressure or systole. The measurement for the periods of rest is called diastolic pressure, or diastole.
Systole supplies your body with blood, and diastole supplies your heart with blood by filling the coronary arteries. Blood pressure is written with the systolic number above the diastolic number. Hypotension in adults is defined as blood pressure of 90/60 or lower.
What causes hypotension?
Everyone’s blood pressure drops at one time or another. And it often doesn’t cause any noticeable symptoms. Certain conditions can cause prolonged periods of hypotension that can become dangerous if left untreated. These conditions 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 accompanies 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, isn’t usually harmful.
Types of hypotension
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.
As the body adjusts to the position change there may be a brief period of dizziness. This is what some people refer to as "seeing stars" when they get up.
Postprandial hypotension is a drop in blood pressure that occurs right after eating. It is a type of orthostatic hypotension. Older adults, especially those with Parkinson’s disease, are more likely to develop postprandial hypotension.
Neurally mediated hypotension happens after you stand for a long time. Children experience this form of hypotension more often than adults. 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.
Treatment for hypotension
Your treatment will depend on the underlying cause of your hypotension. Treatment could include medications for heart disease, diabetes, or infection.
Drink plenty of water to avoid hypotension due to dehydration, especially if you are vomiting or have diarrhea.
Staying hydrated 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. And try to reduce your stress levels to avoid emotional trauma.
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.
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 by understanding the condition and being educated about it. Learn your triggers and try to avoid them as best you can. And if you’re prescribed medication, take it as directed to increase your blood pressure and to avoid potentially harmful complications.
And remember, it’s always best to notify your doctor if you are concerned about your blood pressure levels and any symptoms you might have.
Written by: Erica Roth
Medically reviewed on Jun 24, 2016 by Carissa Stephens, RN, BSN, CCRN, CPN