Low blood pressure, also known as hypotension, is when you have a blood pressure level that is below the normal range.
If your blood pressure is naturally low and isn’t causing you any problems it probably won’t need any treatment. If you have symptoms and your doctor or nurse feels that you would benefit from treatment, they will try to find the cause of your low blood pressure so that they can find the best way to treat it.
Low blood pressure is a reading of less than 90/60mmHg. It does not always cause symptoms, but you may need treatment if it does.
Symptoms of low blood pressure
Get your blood pressure checked if you keep getting symptoms like:
- lightheadedness or dizziness
- feeling sick
- blurred vision
- generally feeling weak
- confusion
- fainting
This might mean your blood pressure is too low.
If you get symptoms when you stand up or suddenly change position, you may have postural hypotension.
How to check your blood pressure
You can check your blood pressure:
- by asking if a pharmacist can do it
- by asking a practice nurse or GP to do it
- at home yourself using a home blood pressure monitor – Blood Pressure UK has information about choosing a blood pressure monitor
Low blood pressure is a measurement of less than 90/60mmHg.
Regular blood pressure check
If you're 40 to 74 years old, you should have your blood pressure checked at least once every 5 years as part of the NHS Health Check.
Non-urgent advice: See a GP if:
- you keep getting symptoms such as dizziness and fainting
Treatment for low blood pressure depends on the cause
If a cause can be found, a GP will be able to recommend treatment to ease your symptoms.
For example, they may suggest:
- changing medicines or altering your dose, if this is the cause
- wearing support stockings – this can improve circulation and increase blood pressure
Medicine to increase blood pressure is rarely needed because simple lifestyle measures or treating the underlying cause is usually effective.
How to ease low blood pressure symptoms yourself
Do
get up slowly from sitting to standing
take care when getting out of bed – move slowly from lying to sitting to standing
eat small, frequent meals – lying down or sitting still for a while after eating may also help
increase the amount of water you drink
Don’t
do not sit or stand for long periods
do not bend down or change posture suddenly
do not drink caffeinated drinks at night
do not drink too much alcohol
Causes of low blood pressure
Your blood pressure can vary depending on the time of day. It gradually increases throughout the day.
What you're doing and how you're feeling can also affect it.
There are many possible causes of low blood pressure. It may be low because you're fit and healthy, or you may have inherited it from your parents.
Low blood pressure occurs when blood pressure is much lower than normal. This means the heart, brain, and other parts of the body do not get enough blood. Normal blood pressure is mostly between 90/60 mmHg and 120/80 mmHg.
The medical name for low blood pressure is hypotension.
Causes
Blood pressure varies from one person to another. A drop as little as 20 mmHg, can cause problems for some people. There are different types and causes of low blood pressure.
Severe hypotension can be caused by sudden loss of blood (shock), severe infection, heart attack, or severe allergic reaction (anaphylaxis).
Orthostatic hypotension is caused by a sudden change in body position. This occurs most often when you shift from lying down to standing. This type of low blood pressure usually lasts only a few seconds or minutes. If this type of low blood pressure occurs after eating, it is called postprandial orthostatic hypotension. This type most often affects older adults, those with high blood pressure, and people with Parkinson disease.
Neurally mediated hypotension (NMH) most often affects young adults and children. It can occur when a person has been standing for a long time. Children usually outgrow this type of hypotension.
Certain medicines and substances can lead to low blood pressure, including:
- Alcohol
- Anti-anxiety medicines
- Certain antidepressants
- Diuretics
- Heart medicines, including those used to treat high blood pressure and coronary heart disease
- Medicines used for surgery
- Painkillers
Other causes of low blood pressure include:
- Nerve damage from diabetes
- Changes in heart rhythm (arrhythmias)
- Not drinking enough fluids (dehydration)
- Heart failure
Symptoms
Symptoms of low blood pressure may include:
- Blurry vision
- Confusion
- Dizziness
- Fainting (syncope)
- Lightheadedness
- Nausea or vomiting
- Sleepiness
- Weakness
Exams and Tests
The health care provider will examine you to determine the cause of your low blood pressure. Your vital signs (temperature, pulse, rate of breathing, and blood pressure) will be checked frequently. You may need to stay in the hospital for a while.
The provider will ask questions, including:
- What is your normal blood pressure?
- What medicines do you take?
- Have you been eating and drinking normally?
- Have you had any recent illness, accident, or injury?
- What other symptoms do you have?
- Did you faint or become less alert?
- Do you feel dizzy or lightheaded when standing or sitting after lying down?
The following tests may be done:
- Basic metabolic panel
- Blood cultures to check for infection
- Complete blood count (CBC), including blood differential
- Electrocardiogram (ECG)
- Urinalysis
- X-ray of the abdomen
- X-ray of the chest
Treatment
Lower than normal blood pressure in a healthy person that does not cause any symptoms often does not need treatment. Otherwise, treatment depends on the cause of your low blood pressure and your symptoms.
When you have symptoms from a drop in blood pressure, sit or lie down right away. Then raise your feet above heart level.
Severe hypotension caused by shock is a medical emergency. You may be given:
- Blood through a needle (IV)
- Medicines to increase blood pressure and improve heart strength
- Other medicines, such as antibiotics
Treatments for low blood pressure after standing up too quickly include:
- If medicines are the cause, your provider may change the dosage or switch you to a different drug. Do not stop taking any medicines before talking to your provider.
- Your provider may suggest drinking more fluids to treat dehydration.
- Wearing compression stockings can help keep blood from collecting in the legs. This keeps more blood in the upper body.
People with NMH should avoid triggers, such as standing for a long period of time. Other treatments include drinking fluids and increasing salt in your diet. Talk to your provider before trying these measures. In severe cases, medicines may be prescribed.
Outlook (Prognosis)
Low blood pressure can usually be treated with success.
Possible Complications
Falls due to low blood pressure in older adults can lead to a broken hip or spine fracture. These injuries can reduce a person’s health and ability to move about.
Sudden severe drops in your blood pressure starves your body of oxygen. This can lead to damage of the heart, brain, and other organs. This type of low blood pressure can be life threatening if not treated right away.
When to Contact a Medical Professional
If low blood pressure causes a person to pass out (become unconscious), seek treatment right away. Or call 911 or the local emergency number. If the person is not breathing or has no pulse, begin CPR.
Call your provider right away if you have any of the following symptoms:
- Black or maroon stools
- Chest pain
- Dizziness, lightheadedness
- Fainting
- Fever higher than 101°F (38.3°C)
- Irregular heartbeat
- Shortness of breath
Prevention
Your provider may recommend certain steps to prevent or reduce your symptoms including:
- Drinking more fluids
- Getting up slowly after sitting or lying down
- Not drinking alcohol
- Not standing for a long time (if you have NMH)
- Using compression stockings so blood does not collect in the legs
Alternative Names
Hypotension; Blood pressure - low; Postprandial hypotension; Orthostatic hypotension; Neurally mediated hypotension; NMH
References
Calkins HG, Zipes DP. Hypotension and syncope. In: Zipes DP, Libby P, Bonow RO, Mann DL, Tomaselli GF, Braunwald E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 11th ed. Philadelphia, PA: Elsevier; 2019:chap 43.
Schrigern DL. Approach to the patient with abnormal vital signs. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 7.
Review Date 1/16/2021
Updated by: Linda J. Vorvick, MD, Clinical Associate Professor, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.