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What Is Blood Pressure?

Understanding the Numbers and Why It Matters

Key Takeaways

Blood pressure is a critical measure of heart health, showing how hard your heart works to circulate blood.
A normal blood pressure is between 90/60 mm Hg and below 120/80 mm Hg, while higher or lower readings can lead to serious health issues.
Systolic and diastolic numbers tell different parts of the story—both are important for diagnosis and monitoring.
Many factors can affect blood pressure, including lifestyle, age, medications, and underlying conditions.
Check your blood pressure regularly and act fast if readings are too high or too low, especially with warning symptoms.

Overview

What Is Blood Pressure?

Blood pressure is the force of blood pushing against the walls of your arteries as your heart pumps it throughout your body. It’s a vital sign of your overall health and plays a critical role in delivering oxygen and nutrients to your organs and tissues.

Why Is Blood Pressure Important?

Monitoring blood pressure helps detect and prevent serious conditions like:

Heart disease
Stroke
Kidney disease
Vision loss

High or low blood pressure can lead to long-term complications if left untreated. That’s why it’s often called the “silent killer”—you may not feel symptoms until it causes serious harm.

How Is Blood Pressure Measured?

Blood pressure is measured using a cuff placed around your limb, often your arm, either manually with a stethoscope or digitally using an automatic monitor. Results are given as two numbers (e.g., 120/80 mm Hg).

What is Blood Pressure?

- Cardiologist Zacharia Nealy, MD explains what blood pressure is and how it impacts our overall health.

Understanding Blood Pressure Numbers

What Are Systolic and Diastolic Readings?

Systolic pressure (top number): Measures the pressure in your arteries when your heart beats.
Diastolic pressure (bottom number): Measures the pressure between heartbeats when the heart is at rest.

How to Read Your Blood Pressure

Category	Systolic	Diastolic
Normal	Less than 120	Less than 80
Elevated	120-129	Less than 80
High Blood Pressure (Stage 1)	130-139	80-89
High Blood Pressure (State 2)	140 or higher	90 or higher
Hypertensive Crisis	Over 180	Over 120
Low Blood Pressure (Hypotension)	Less than 90	Less than 60

What Is Normal?

A normal blood pressure is between 90/60 mm Hg and below 120/80 mm Hg. Maintaining this range supports healthy circulation and reduces the risk of cardiovascular complications.

What Is Hypertension vs. Hypotension?

Hypertension [LINK to High Blood Pressure condition page] is high blood pressure, which increases the risk of heart attack, stroke, and other health problems.
Hypotension [LINK to Low Blood Pressure condition page] is low blood pressure, which may cause dizziness, fainting, and fatigue, especially if blood flow to the brain is reduced.

What Causes Changes in Blood Pressure?

Non-Controllable Factors

Age (blood pressure tends to rise with age)
Genetics or family history
Underlying medical conditions like kidney disease, diabetes, or hormonal disorders
Pregnancy-related conditions like preeclampsia [LINK to https://www.riversideonline.com/patients-and-visitors/healthy-you-blog/blog/w/what-is-preeclampsia ]

Controllable Factors

Diet high in sodium or low in potassium
Lack of physical activity
Smoking or excessive alcohol use
Being overweight or obese
Chronic stress
Certain medications (e.g., decongestants, NSAIDs)

When to Seek Care for Blood Pressure Issues

Symptoms of High Blood Pressure

Most people with high blood pressure don’t experience noticeable symptoms, but some may have:

Headaches
Nosebleeds
Shortness of breath
Vision changes

These signs often appear only when blood pressure is dangerously high.

Symptoms of Low Blood Pressure

Lightheadedness or dizziness
Fainting
Blurred vision
Fatigue
Nausea

When to Seek Emergent Medical Care

Seek emergency care if:
Your blood pressure is 180/120 or higher
You experience chest pain, confusion, difficulty speaking, shortness of breath, or signs of a stroke

These may indicate a hypertensive crisis or cardiovascular emergency.

What Should You Do Next?

Have your blood pressure checked regularly, especially if you're over 40 or have risk factors.
Track your readings with a home blood pressure monitor.
Make healthy lifestyle choices—diet, exercise, sleep, and stress management matter.
Talk to your healthcare provider if your blood pressure is consistently too high or too low.
Follow your treatment plan, which may include lifestyle changes and/or medication.