What is blood pressure?

Blood pressure measures the extent of the force of blood on your blood vessel walls as your heart pumps. It’s measured in millimeters of mercury (mm Hg).

Systolic blood pressure is the top number in a reading. It measures the pressure on blood vessels as your heart squeezes blood out to your body.

Diastolic blood pressure is the bottom number in a reading. It measures the pressure on blood vessels in between heart beats, while your heart fills up with blood returning from your body.

It’s important to manage your blood pressure:

  • Hypertension, or blood pressure that’s too high, can put you at risk for heart disease, vision loss, kidney failure, and stroke.
  • Hypotension, or blood pressure that’s too low, can cause serious side effects, such as dizziness or fainting. Severely low blood pressure can damage organs by depriving them of blood flow and oxygen.

Know your blood pressure numbers

To manage your blood pressure, you need to know which blood pressure numbers are ideal and which ones are cause for concern. Following are the blood pressure ranges used to diagnose hypotension and hypertension in adults.

In general, hypotension relates more to symptoms and specific situations than to exact numbers. The numbers for hypotension serve as a guide, while the numbers for hypertension are more precise.

Systolic (top number)Diastolic (bottom number) Blood pressure category
90 or below60 or belowhypotension
91 to 11961 to 79normal
between 120 and 129and below 80elevated
between 130 and 139or between 80 and 89stage 1 hypertension
140 or higheror 90 or higherstage 2 hypertension
higher than 180higher than120 hypertensive crisis

When looking at these numbers, notice that only one of them needs to be too high to put you in a hypertensive category. For example, if your blood pressure is 119/81, you’d be considered to have stage 1 hypertension.

Blood pressure levels for children

Blood pressure levels are different for children than they are for adults. Blood pressure targets for children are determined by several factors, such as:

  • age
  • gender
  • height

Talk to your child’s pediatrician if you’re concerned about their blood pressure. The pediatrician can walk you through the charts and help you understand your child’s blood pressure.

How to take a reading

There are a few ways to check your blood pressure. For example, your doctor can check your blood pressure in their office. Many pharmacies also offer free blood pressure monitoring stations.

You can also check it at home using home blood pressure monitors. These are available for purchase from pharmacies and medical supply stores.

The American Heart Association recommends using an automatic home blood pressure monitor that measures blood pressure on your upper arm. Wrist or finger blood pressure monitors are also available but may not be as accurate.

When taking your blood pressure, make sure you:

  • sit still, with your back straight, feet supported, and legs uncrossed
  • keep your upper arm at heart level
  • make sure the middle of the cuff rests directly above the elbow
  • avoid exercise, caffeine, or smoking for 30 minutes before you take your blood pressure


Your reading may indicate a blood pressure problem even if only one number is high. No matter what category of blood pressure you have, it’s important to monitor it regularly. Talk to your doctor about how often you should check your blood pressure at home.

Write the results in a blood pressure journal and share them with your doctor. It’s a good idea to take your blood pressure more than once at one sitting, around three to five minutes apart.

For high blood pressure

If you have high blood pressure, your doctor may watch it closely. This is because it’s a risk factor for heart disease.

Elevated blood pressure is a condition that puts you at risk for hypertension. If you have it, your doctor may suggest lifestyle changes such as eating a heart-healthy diet, cutting back on alcohol, and exercising regularly. These may help bring your blood pressure numbers down. You may not need prescription drugs.

If you have stage 1 hypertension, your doctor may suggest lifestyle changes and medication. They may prescribe a drug such as a water pill or diuretic, an angiotensin converting enzyme (ACE) inhibitor, an angiotensin II receptor blocker (ARB), or a calcium channel blocker.

Stage 2 hypertension may require treatment with lifestyle changes and a combination of medications.

For low blood pressure

Low blood pressure needs a different treatment approach. Your doctor may not treat it at all if you don’t have symptoms.

Low blood pressure is often caused by another health condition, such as a thyroid problem, medication side effects, dehydration, diabetes, or bleeding. Your doctor will likely treat that condition first.

If it’s unclear why your blood pressure is low, treatment options may include:

  • eating more salt
  • drinking more water
  • wearing compression stockings to help prevent blood from pooling in your legs
  • taking a corticosteroid such as fludrocortisone to help increase blood volume


Unmanaged high or low blood pressure may cause serious complications.

High blood pressure is much more common than low blood pressure. It’s hard to know when your blood pressure is high unless you’re monitoring it. High blood pressure doesn’t cause symptoms until you’re in hypertensive crisis. A hypertensive crisis requires emergency care.

Left unmanaged, high blood pressure may cause:

On the other hand, low blood pressure may cause:

  • dizziness
  • fainting
  • injury from falls
  • heart damage
  • brain damage
  • other organ damage


Lifestyle changes can help prevent high blood pressure. Try the following tips.

  • Eat a heart-healthy diet that includes plenty of fruits and vegetables, whole grains, healthy fats, and low-fat protein.
  • Reduce your sodium consumption. The American Heart Association recommends keeping your sodium intake below 2400 milligrams (mg) with ideally no more than 1500 mg per day.
  • Watch your portions to help maintain a healthy weight.
  • Stop smoking.
  • Exercise regularly. If you aren’t currently active, start slowly and work your way up to 30 minutes of exercise most days.
  • Practice stress-relief techniques, such as meditation, yoga, and visualization. Chronic stress or very stressful events can send blood pressure soaring, so managing your stress may help manage your blood pressure.

Talk to your doctor

People with chronic, uncontrolled high blood pressure are more likely to develop a life-threatening condition.

If you have low blood pressure, your outlook depends on its cause. If it’s caused by an untreated underlying condition, your symptoms may escalate.

You can reduce your risk of serious complications by managing your high or low blood pressure. This can involve lifestyle changes and medications, if prescribed. Talk to your doctor to find the best treatment for you.