High blood pressure, also known as hypertension, is a common heart condition worldwide. It happens when blood pressure against the artery walls stays higher than normal for an extended period.
Blood pressure can change throughout the day due to factors like exercise, stress, anxiety, pain, and caffeine. A temporary increase in blood pressure does not mean someone has hypertension. A diagnosis is usually based on multiple blood pressure readings taken over time, rather than just one measurement (Jones et al., 2025).
What Do Blood Pressure Numbers Mean?
Blood pressure is measured in millimeters of mercury (mm Hg) and consists of two numbers.
The systolic blood pressure is the top number, indicating the pressure in the arteries when the heart beats and pumps blood.
The diastolic blood pressure is the bottom number, showing the pressure in the arteries when the heart is resting between beats.
For example, a reading of 118/76 mm Hg means the systolic pressure is 118 mm Hg and the diastolic pressure is 76 mm Hg.
Why Hypertension Is Often Called a Silent Condition
Hypertension is often called a silent condition because many people do not notice any symptoms. Blood pressure can be high for years without any obvious signs. Therefore, it is important to check blood pressure regularly for early detection (American Heart Association, 2025a).
Some individuals with very high blood pressure may experience symptoms like:
- Headache
- Shortness of breath
- Nosebleeds
- Chest discomfort
- Changes in vision
- Weakness or numbness
However, these symptoms are not specific to hypertension and can occur with other health issues. Severe symptoms like chest pain, neurological changes, or difficulty breathing may indicate a medical emergency (American Heart Association, 2025b).
Blood Pressure Classification Criteria
The American Heart Association and American College of Cardiology classify blood pressure in nonpregnant adults as follows:
| Classification | Systolic Blood Pressure | Diastolic Blood Pressure |
|---|---|---|
| Normal | Less than 120 mm Hg | and less than 80 mm Hg |
| Elevated | 120–129 mm Hg | and less than 80 mm Hg |
| Stage 1 Hypertension | 130–139 mm Hg | or 80–89 mm Hg |
| Stage 2 Hypertension | 140 mm Hg or higher | or 90 mm Hg or higher |
| Severe Hypertension | Higher than 180 mm Hg | and/or higher than 120 mm Hg |
| Hypertensive Emergency | Higher than 180 mm Hg | and/or higher than 120 mm Hg with symptoms or signs of organ damage |
Classification adapted from the 2025 AHA/ACC hypertension guideline (Jones et al., 2025).
Both numbers are important. For instance, a blood pressure of 125/85 mm Hg is classified as Stage 1 hypertension because the diastolic number is between 80 and 89 mm Hg, even though the systolic number is below 130.
What Happens If Blood Pressure Is Too High?
Chronic hypertension puts extra stress on the heart and blood vessels. If not treated, it can lead to serious health issues like heart attack, stroke, and kidney disease (Jones et al., 2025).
Fortunately, hypertension is often manageable.
To prevent and manage high blood pressure, lifestyle changes are recommended, such as maintaining a healthy weight, following a heart-healthy diet like the DASH diet, reducing salt intake, staying active, managing stress, and limiting or avoiding alcohol (Jones et al., 2025).
Depending on blood pressure levels, heart health risks, and other health conditions, medication may also be needed.
When Is High Blood Pressure an Emergency?
A blood pressure reading higher than 180/120 mm Hg is a medical emergency.
If you get a reading above this level, wait at least one minute and check your blood pressure again. If it is still very high, contact a healthcare professional right away.
If a reading above 180/120 mm Hg is accompanied by symptoms like chest pain, shortness of breath, weakness, numbness, vision changes, difficulty speaking, or severe new symptoms, seek emergency medical care immediately (American Heart Association, 2025b).
Take Your Blood Pressure Medication as Prescribed
If you have been diagnosed with hypertension, take your medications exactly as directed. Do not change the dose or stop taking your medication just because your blood pressure improves unless your healthcare provider tells you to.
A normal blood pressure reading while on medication may indicate that the treatment is effective, not that hypertension is gone.
Regular monitoring, healthy lifestyle choices, and appropriate medical treatment can significantly reduce the long-term risks associated with high blood pressure.
References
American Heart Association. (2025a). What is high blood pressure? https://www.heart.org/en/health-topics/high-blood-pressure/the-facts-about-high-blood-pressure
American Heart Association. (2025b). When to call 911 about high blood pressure. https://www.heart.org/en/health-topics/high-blood-pressure/understanding-blood-pressure-readings/when-to-call-911-for-high-blood-pressure
Jones, D. W., Ferdinand, K. C., Taler, S. J., Johnson, H. M., Shimbo, D., Abdalla, M., Altieri, M. M., Bansal, N., Bello, N. A., Bress, A. P., Carter, J., Cohen, J. B., Collins, K. J., Commodore-Mensah, Y., Davis, L. L., Egan, B., Khan, S. S., Lloyd-Jones, D. M., Melnyk, B. M., … Williamson, J. D. (2025). 2025 AHA/ACC/AANP/AAPA/ABC/ACCP/ACPM/AGS/AMA/ASPC/NMA/PCNA/SGIM guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: A report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation, 152, e114–e218. https://doi.org/10.1161/CIR.0000000000001356
Sources / References
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This article is educational and is not medical advice, diagnosis, or treatment. Read the full medical disclaimer.