What is low blood pressure?
Low blood pressure (hypotension) occurs when blood pressure drops below the normal range. Doctors generally define low blood pressure as 90/60 mm Hg or below, commonly said as “90 over 60” Usually, doctors only treat hypotension if it is severe enough to cause symptoms.
Low blood pressure can be temporary, or it can be a chronic (long-lasting) condition. The main types of hypotension are:
- Orthostatic hypotension: People with orthostatic hypotension (sometimes called postural hypotension) feel faint or lightheaded when they stand up or change position suddenly.
- Postprandial hypotension: This condition causes people to feel lightheaded or dizzy after eating a meal because their blood pressure drops suddenly.
- Neurally mediated hypotension: People with this disorder feel faint, dizzy, and nauseous after exercising or standing for a long time.
- Severe hypotension linked to shock: Shock is the most extreme form of hypotension. When a person is in shock, blood pressure drops to dangerously low levels, and the brain and organs can’t get enough blood to function.
What is blood pressure?
As blood pumps through the circulatory system, it pushes against the walls of the arteries and veins. Blood pressure is the force of the blood as it presses against the blood vessel walls. It is measured in systolic pressure (when the blood is pumping) and diastolic pressure (between beats, when your heart is at rest).
Blood pressure rises and falls throughout the day. Normal blood pressure is considered to be below 120/80 mm Hg. In a blood pressure reading, the top number refers to systolic pressure, and the bottom number refers to the diastolic pressure.
How common is low blood pressure?
Hypotension is fairly common, and different types are more likely to occur in certain groups of people. Orthostatic hypotension is common in pregnant women and older adults. Postprandial hypotension is common in older people.
Who is affected by low blood pressure?
Low blood pressure can affect people of all ages, although it is more common in older people who are frail or bedridden. Pregnant women and older adults are more likely to have orthostatic hypotension. Children and young adults are most likely to experience neurally mediated hypotension, but they often outgrow it.
Hypotension commonly affects people who:
- Are taking certain medications that cause low blood pressure.
- Have hormonal imbalances or vitamin deficiencies.
- Also have heart problems or liver disease.
Symptoms and Causes
What causes low blood pressure?
Low blood pressure is often a sign of another medical condition. Hypotension has a variety of causes. They include:
- Heart disease or other heart problems, such as fast heart rate (tachycardia) or very slow heart rate (bradycardia).
- Certain medications, such as those for depression, Parkinson’s disease, or erectile dysfunction.
- Intense emotions like fear or pain.
- Blood loss or blood infection.
- Extreme changes in body temperature.
What are the symptoms of low blood pressure?
Symptoms of low blood pressure can come on suddenly or slowly get worse over time. They include:
- Dizziness, lightheadedness, and fainting.
- Blurred vision.
- Skin that is cold and sweaty.
- Quick, shallow breathing.
What can you do to help relieve symptoms of low blood pressure?
Depending on the type of low blood pressure you have, you may be able to relieve some of your symptoms by:
- Eating a healthy diet with fewer carbohydrates and smaller meals.
- Drinking more water and avoiding alcohol.
- Getting up slowly after you’ve been sitting or lying down.
- Focusing on breathing a few times before you change position.
- Wearing compression stockings.
Diagnosis and Tests
How is low blood pressure diagnosed?
Your doctor will ask about your symptoms and take your blood pressure by placing a blood pressure cuff around your upper arm. The cuff will tighten on your arm, and the monitor will measure your systolic and diastolic pressure. A blood pressure reading of 90/60 mm Hg (or lower) is considered low blood pressure.
Low blood pressure may be a sign of an underlying condition, so your doctor will try to determine what caused your blood pressure to drop. Depending on your medical history and symptoms, your doctor may also check your heart using an echocardiogram, electrocardiogram, or stress test. Your doctor may also perform blood tests to check for:
- Hypoglycemia (low blood sugar).
- Vitamin deficiencies.
- Thyroid problems.
- Hormonal imbalances.
How do I know if I have low blood pressure?
If you have any symptoms of low blood pressure, you should visit your doctor to get your blood pressure checked. Because the signs of low blood pressure can be similar to those of other conditions, it is important to see your doctor so you can be monitored.
Management and Treatment
What are the treatments for low blood pressure?
The treatments for low blood pressure depend on what caused the condition. Your doctor will work with you to address the cause of the hypotension. In severe cases of hypotension, your doctor may give you IV fluids to raise your blood pressure.
Depending on a variety of factors, such as your age and the type of hypotension, your doctor may recommend one or more of the following: dietary changes, lifestyle changes and/or medications.
To make dietary changes, your doctor might tell you to:
- Stay hydrated by drinking more water throughout the day.
- Drink less alcohol.
- Increase your salt intake slightly because sodium raises blood pressure.
- Eat smaller, healthy meals and limit carbohydrates.
You can take several steps to avoid a sudden drop in blood pressure. Your doctor may recommend that you make the following lifestyle changes:
- Wear compression stockings.
- Get up slowly after you’ve been sitting or lying down.
- Avoid standing for long periods of time.
- Sit up and breathe deeply for a few minutes before getting out of bed.
Your doctor might prescribe medications like:
What are the side effects of the treatment for low blood pressure?
There are no side effects for the lifestyle and dietary changes that can treat hypotension.
The medications used to treat hypotension have several side effects, some of which may be serious. Fludrocortisone can make certain infections worse, so it’s essential to discuss this medication with your doctor. The most common side effects from fludrocortisone are:
- Increased risk of infection.
- Nausea, bloating, or other stomach problems.
- Insomnia (problems sleeping).
The most common side effects from midodrine are:
- Numbness or tingling.
- Goosebumps and chills.
What are the complications associated with low blood pressure?
While it’s not usually a serious medical condition, hypotension can cause injuries due to fainting and falling. If hypotension is left untreated, the brain, heart and other organs can’t get enough blood and cannot work properly. Severe hypotension can lead to shock, which can be fatal.
How can you prevent low blood pressure?
You may be able to prevent hypotension by making changes to your lifestyle and diet, such as:
- Eating fewer carbohydrates and choosing small, healthy meals.
- Staying hydrated and avoiding alcoholic drinks.
- Rising slowly when you’ve been sitting or lying down.
- Taking a few deep breaths before you change position.
- Wearing compression stockings.
Outlook / Prognosis
What is the outlook for patients who have low blood pressure?
Low blood pressure that is monitored does not usually cause serious or long-term health problems, especially when doctors can treat any underlying condition. Many people learn to manage hypotension with dietary and lifestyle changes.
When should you call your doctor about low blood pressure?
If you have recurring dizziness or fainting, or other symptoms of low blood pressure, you should visit your doctor. Sudden drops in blood pressure can be dangerous. It is important for your doctor to determine why your blood pressure is dropping and treat the cause.