Blood pressure is a measurement of 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 heartbeats while your heart fills up with blood returning from your body.

It’s important to manage your blood pressure.

Hypotension, or blood pressure that’s too low, can cause serious symptoms, like dizziness or fainting. Severely low blood pressure can damage organs by depriving them of blood flow and oxygen.

Hypertension, or blood pressure that’s too high, can put you at risk for:

To manage your blood pressure, you need to know which blood pressure numbers are ideal and which ones are cause for concern.

In general, meeting the criteria for hypotension has more to do with symptoms and specific situations than with exact numbers. But institutions like the National Heart, Lung, and Blood Institute and the United Kingdom’s National Health Service (NHS) consider people hypotensive if their blood pressure falls within this range:

Systolic blood pressure (top number) in mm HgDiastolic blood pressure (bottom number) in mm HgBlood pressure category
90 or belowAnd 60 or belowHypotension

The numbers for hypotension serve as a guide, while the numbers for hypertension are more precise. According to the American Heart Association (AHA), these ranges represent normal, elevated, or high blood pressure:

Systolic blood pressure (top number) in mm HgDiastolic blood pressure (bottom number) in mm HgBlood pressure category
Below 120, and…below 80Normal
Between 120 and 129, and…below 80Elevated
Between 130 and 139, or…between 80 and 89Stage 1 hypertension
140 or higher, or…90 or higherStage 2 hypertension
Higher than 180, or…higher than 120Hypertensive 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. Children’s blood pressure targets are determined by several factors, like their age, sex, and height.

Talk with 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.

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 AHA 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 take the following steps:

  • Sit still, with your back straight, feet supported, and legs uncrossed.
  • Keep your upper arm at heart level.
  • Have the middle of the cuff rest 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 with a doctor about how often you should check your blood pressure at home.

Write the results in a blood pressure journal and share them with the doctor. It’s a good idea to take your blood pressure more than once at one sitting, with 1 minute between each reading.

For low blood pressure

Your doctor may not treat low blood pressure if you don’t have symptoms.

Low blood pressure is often caused by another health condition or concern, like:

The doctor will likely address that health condition or concern first.

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

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.

Having elevated blood pressure puts you at risk for high blood pressure. If your blood pressure is elevated, your doctor may suggest lifestyle changes like 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 medications.

If you have stage 1 hypertension, your doctor may suggest lifestyle changes and medication. They may prescribe a drug like:

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

Unmanaged low or high blood pressure may cause serious complications.

If your blood pressure’s low

Low blood pressure may cause:

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

If your blood pressure’s high

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 since high blood pressure doesn’t cause symptoms until you’re in hypertensive crisis. A hypertensive crisis requires emergency medical care.

Left unmanaged, high blood pressure may cause:

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

Tips to prevent high blood pressure

People with chronic, untreated 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 low or high blood pressure. This can involve lifestyle changes and prescribed medications. Talk with a doctor to find the best treatment for you.

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