If you buy something through a link on this page, we may earn a small commission. How this works.

Maintaining optimal blood pressure plays an essential role in reducing the risk of serious health problems, such as heart attacks, heart failure, and stroke.

Keep reading for more information about blood pressure and what are normal and abnormal readings.

a blood pressure chart infographic

Blood pressure refers to the force that blood puts on the walls of the blood vessels as the heart pumps blood. Healthcare professionals measure blood pressure in millimeters of mercury (mm Hg).

Doctors can use blood pressure as an indicator of a person's heart health. People with high blood pressure — or hypertension — are at risk of developing heart problems and damage to the walls of the blood vessels.

Low blood pressure — or hypotension — is a sign of good health, but can be abnormal in certain situations, such as during severe infection.

If blood pressure falls too low, it can cause people to feel dizzy or light-headed and, in extreme cases, can compromise blood flow to the organs.

Severe hypotension can increase the risk of organ damage and fainting due to the loss of oxygen-rich blood.

Typically, a person can keep their blood pressure in the normal range by maintaining a healthy weight through a healthful diet that limits alcohol and salt intake, and by exercising regularly. If they are having trouble with blood pressure, a doctor may be able to prescribe medication to help regulate it.

There are two numbers in a blood pressure reading. People often call these the upper (systolic) and lower (diastolic) numbers.

Systolic is the top number on the reading and is the higher one. Diastolic is the lower number.

A person should keep these numbers within the normal range to prevent either hypertension or hypotension. We describe the healthy ranges for systolic and diastolic readings below.

According to the American Heart Association, a healthy blood pressure range is:

  • systolic: less than 120
  • diastolic: less than 80

If a person has the following numbers, they have low blood pressure:

  • systolic: 90 or below
  • diastolic: 60 or below

Lower blood pressure is especially common in athletes and young people.

A person has elevated blood pressure if their readings are:

  • systolic: 120–129
  • diastolic: less than 80

A person with elevated blood pressure is not yet hypertensive and can take steps to help prevent progression to hypertension.

Actions include:

  • reducing sodium intake
  • exercising more frequently
  • losing weight
  • treating other conditions that may be contributing, such as sleep apnea
  • limiting alcohol intake
  • taking medications that target blood pressure

The three stages of hypertension are:

  • stage 1
  • stage 2
  • crisis

In stage 1 hypertension, the numbers will range between:

  • systolic: 130–139 or
  • diastolic: 80–89

In stage 2 hypertension, the numbers will range between:

  • systolic: 140 or higher or
  • diastolic: 90 or higher

Finally, if a person has hypertension crisis, the numbers will read:

  • systolic: 180 or higher
  • diastolic: 120 or higher

These numbers are for adults. A parent or caregiver should talk to a child's doctor about healthy ranges for children, as age, weight, and sex can all affect these numbers.

If a person has hypertension, their blood pressure is too high.

When a person is hypertensive, they are at an increased risk of developing conditions, such as:

In most cases, there are no symptoms of high blood pressure.

However, a person who is experiencing a hypertension crisis due to elevated blood pressure levels may experience the following symptoms:

  • difficulty speaking
  • chest pain
  • back pain
  • change in vision or blurry vision
  • shortness of breath due to fluid in the lungs
  • numbness or weakness
  • headache

Anyone experiencing these symptoms should seek immediate medical treatment.

When a person has severe hypotension, their blood pressure is too low.

Though many doctors often stress the importance of lowering blood pressure, it is possible for someone's blood pressure to be too low.

People with very low blood pressure may experience the following symptoms:

  • fainting
  • dizziness/lightheadedness
  • nausea
  • heart palpitations
  • fatigue
  • blurry vision
  • injury from falling or loss of consciousness
  • organ damage in severe cases

People's blood pressure is partially due to factors they cannot control, such as:

However, there are also many steps a person can take to prevent high blood pressure. These include:

eating a healthful diet that includes fruits, vegetables, lean proteins, and complex carbohydrates

exercising regularly, particularly cardio workouts, such as walking, cycling, or running

  • not smoking
  • limiting alcohol consumption
  • restricting consumption of processed foods
  • limiting sodium intake to less than 2,000 grams daily
  • treating sleep apnea
  • managing and regulating diabetes
  • reducing weight if overweight
  • taking steps to reduce stress

If a person experiences any symptoms of critical hypertension, they should seek immediate medical attention to prevent serious complications.

A person should also receive regular blood pressure readings at check-ups with their doctor or other healthcare professionals.

However, a person can also take their blood pressure at home using an over-the-counter blood pressure monitor. If the blood pressure reader indicates a person has high or low blood pressure, they should talk to their doctor.

Blood pressure monitors are available in pharmacies and online.

Blood pressure is one indicator of a person's heart health. If the pressure is too high, it can lead to serious health complications and potentially death.

Though not all causes of elevated blood pressure are preventable, a person can reduce their risk of complications by managing their lifestyle and minimizing risk factors for developing high blood pressure.

Anyone concerned about high or low blood pressure should speak to a doctor.