Conditions guide

High Blood Pressure (Hypertension)

High blood pressure, or hypertension, means the force of blood pushing against artery walls is consistently higher than normal. It usually causes no symptoms but raises the risk of heart disease, stroke, and kidney disease over time.

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At a Glance

  • High blood pressure is very common and often has no symptoms, which is why it is sometimes called a silent condition.
  • Blood pressure is written as two numbers: systolic (top) over diastolic (bottom), measured in mmHg.
  • In the US, guidelines generally define hypertension as readings of 130/80 mmHg or higher on repeated measurements.
  • Over time, uncontrolled high blood pressure can damage the heart, brain, kidneys, and eyes.
  • Lifestyle changes and medicines are the main approaches used to lower blood pressure.
  • Regular blood pressure checks are the only reliable way to know if it is high.

What It Is

Every heartbeat pushes blood through the arteries. Blood pressure is the force of that blood against artery walls. The systolic number reflects pressure when the heart beats, and the diastolic number reflects pressure when the heart rests between beats.

When blood pressure stays high over months and years, the heart has to work harder and the arteries can become stiffer and narrower. This added strain contributes to heart attack, stroke, heart failure, kidney disease, and vision problems.

Most adults with high blood pressure have primary (essential) hypertension, which develops gradually without one identifiable cause. Secondary hypertension is caused by another condition, such as kidney disease, certain hormone disorders, sleep apnea, or some medicines.

Common Terminology

Systolic pressure
The top number in a blood pressure reading, showing pressure in the arteries when the heart contracts.
Diastolic pressure
The bottom number, showing pressure in the arteries when the heart relaxes between beats.
mmHg
Millimeters of mercury, the standard unit used to measure blood pressure.
Elevated blood pressure
A US guideline category for systolic readings of 120 to 129 with diastolic below 80, which is above normal but below the hypertension range.
White coat hypertension
Blood pressure that reads higher in a clinic setting than it does at home or in daily life.
Hypertensive crisis
A severe rise in blood pressure, generally around 180/120 mmHg or higher, which may need urgent medical attention.
Secondary hypertension
High blood pressure caused by another identifiable condition or medicine.

Common Causes and Associations

High blood pressure usually develops from a combination of factors over time.

  • Increasing age is associated with stiffer arteries and higher blood pressure.
  • Family history and genetics can make high blood pressure more likely.
  • Eating a lot of sodium (salt) and too little potassium is linked with higher blood pressure.
  • Physical inactivity and excess body weight are common contributing factors.
  • Heavy alcohol use and tobacco use are associated with raised blood pressure and artery damage.
  • Chronic stress and poor sleep may contribute.
  • Conditions such as kidney disease, diabetes, sleep apnea, and thyroid or adrenal disorders can raise blood pressure.

Symptoms and Features

This is a general description, not a diagnostic checklist. Most people with high blood pressure have no symptoms at all, and symptoms are not a reliable way to tell if blood pressure is high.

  • High blood pressure usually causes no noticeable symptoms, even when readings are quite high.
  • Very high blood pressure may sometimes be associated with severe headache, chest pain, shortness of breath, vision changes, or confusion.
  • Many people learn they have high blood pressure during a routine checkup or screening.
  • Signs of long-term effects can include changes in the eyes, kidney function, or heart seen on tests.
  • Blood pressure naturally varies throughout the day, so a single high reading does not by itself mean hypertension.

Tests and Evaluation

Diagnosis is based on repeated blood pressure measurements, and other tests may be used to look for causes or effects on the body.

  • Blood pressure is measured with a cuff on the upper arm, ideally after sitting quietly for several minutes.
  • Readings are usually repeated on different occasions before a diagnosis is made.
  • Home blood pressure monitoring or 24-hour ambulatory monitoring can confirm readings outside the clinic.
  • Blood and urine tests may check kidney function, electrolytes, blood sugar, and cholesterol.
  • An electrocardiogram (ECG) may be used to look at the heart's rhythm and signs of strain.
  • Additional tests may be considered when a secondary cause is suspected.

Treatment Overview

Treatment is generally individualized by a clinician based on blood pressure levels and overall cardiovascular risk.

  • Lifestyle approaches commonly recommended include reducing sodium, eating a heart-healthy pattern such as the DASH diet, and staying physically active.
  • Maintaining a healthy weight, limiting alcohol, and not smoking are also commonly advised.
  • Several classes of medicines are used, including ACE inhibitors, angiotensin receptor blockers (ARBs), calcium channel blockers, and thiazide diuretics.
  • Some people need more than one type of medicine to reach their blood pressure goal.
  • Treatment goals are set by a clinician and may differ based on age and other health conditions.
  • Ongoing monitoring, including home readings, helps clinicians assess how well treatment is working.

When Professional Care May Be Discussed

Very high blood pressure with symptoms such as chest pain, shortness of breath, back pain, numbness or weakness, vision changes, or difficulty speaking is generally treated as a medical emergency; in the US, people are advised to call 911.

  • Regular blood pressure checks are generally recommended for adults as part of routine care.
  • Home readings that are consistently above normal are often shared with a healthcare professional.
  • Side effects that may be related to blood pressure medicines are typically discussed with a clinician or pharmacist.
  • Pregnancy with high blood pressure readings is generally monitored closely because of conditions like preeclampsia.
  • Readings around 180/120 mmHg or higher are generally considered to need prompt medical evaluation, even without symptoms.

Questions to Ask a Healthcare Professional

General questions people often find useful to bring to an appointment:

  • What do the two numbers in a blood pressure reading mean?
  • How is high blood pressure confirmed, and why are repeat readings important?
  • What is the correct way to measure blood pressure at home?
  • What blood pressure goal is generally used, and does it vary by person?
  • Which lifestyle changes tend to have the biggest effect on blood pressure?
  • Could another condition or medicine be contributing to high blood pressure?
  • How often is blood pressure usually rechecked once treatment begins?

Sources

This guide was written in plain language from the following authoritative references.

  1. High Blood Pressure — MedlinePlus (U.S. National Library of Medicine)
  2. High Blood Pressure — National Heart, Lung, and Blood Institute (NHLBI)
  3. High blood pressure (hypertension) — NHS

Last updated October 8, 2026. FreeDoc guides are general educational information and are not a substitute for care from a qualified professional.