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Last updated: April 4, 2026

Quick Answer: To check your blood pressure, a healthcare professional will use a device called a sphygmomanometer. This device typically involves an inflatable cuff placed around your arm, a gauge to measure pressure, and a bulb to inflate the cuff. The reading will indicate your systolic pressure (when the heart beats) and diastolic pressure (when the heart rests between beats).

Key Facts

Blood pressure is measured in millimeters of mercury (mmHg).
Normal blood pressure is generally considered to be below 120/80 mmHg.
High blood pressure (hypertension) is diagnosed when readings are consistently 130/80 mmHg or higher.
Low blood pressure (hypotension) can occur for various reasons and is often considered problematic if it causes symptoms.
Checking blood pressure can be done at home with an automated monitor, but readings should ideally be confirmed by a doctor.

Overview

Checking your blood pressure is a fundamental part of monitoring your cardiovascular health. Blood pressure is the force of blood pushing against the walls of your arteries as your heart pumps it around your body. It's crucial to understand what your blood pressure reading means and how it's taken to ensure you are maintaining a healthy range.

What is Blood Pressure?

Blood pressure is recorded as two numbers, typically written one above the other or separated by a slash. The top number is called the systolic pressure, and it represents the pressure in your arteries when your heart muscle contracts (beats). The bottom number is called the diastolic pressure, and it represents the pressure in your arteries when your heart muscle is resting between beats.

For example, a blood pressure reading of 120/80 mmHg means that the systolic pressure is 120 millimeters of mercury and the diastolic pressure is 80 millimeters of mercury.

How is Blood Pressure Measured?

The most common method for measuring blood pressure is using a sphygmomanometer, which consists of:

An inflatable cuff: This is wrapped around your upper arm.
A measuring unit: This can be an aneroid gauge (a dial) or a digital display that shows the pressure reading.
An inflation bulb: Used to inflate the cuff (in manual devices).

There are two main types of sphygmomanometers:

Aneroid (manual) sphygmomanometers: These require a stethoscope to listen for the sounds of blood flow in the artery. A healthcare professional will inflate the cuff until blood flow stops and then slowly release the pressure, listening for specific sounds (Korotkoff sounds) to determine the systolic and diastolic pressures.
- Systolic pressure is the point at which you first hear the tapping sound.
- Diastolic pressure is the point at which the sound disappears completely.
Digital (automatic) sphygmomanometers: These are electronic devices that use an oscillometric method to detect blood flow and pressure. They automatically inflate and deflate the cuff and display the systolic and diastolic readings, as well as the pulse rate, on a screen. These are commonly used for home monitoring.

Where and When to Check Blood Pressure

Blood pressure can be checked:

At a doctor's office or clinic: This is the most common place, and readings taken here are considered authoritative.
At a pharmacy or retail store: Many offer automated blood pressure machines in a public area.
At home: Using a validated, automated home blood pressure monitor. It's recommended to check your blood pressure at the same time each day, in a quiet environment after resting for at least 5 minutes, and with your arm supported at heart level. Avoid caffeine, exercise, and smoking for at least 30 minutes before measuring.

It's important to note that blood pressure can fluctuate throughout the day. A single high reading doesn't necessarily mean you have hypertension, just as a single low reading doesn't automatically indicate hypotension. Consistent readings are key for diagnosis.

Understanding Your Blood Pressure Readings

The American Heart Association provides the following categories for blood pressure in adults:

Normal: Less than 120/80 mmHg
Elevated: Systolic between 120-129 mmHg and diastolic less than 80 mmHg
Hypertension Stage 1: Systolic between 130-139 mmHg or diastolic between 80-89 mmHg
Hypertension Stage 2: Systolic 140 mmHg or higher or diastolic 90 mmHg or higher
Hypertensive Crisis: Systolic higher than 180 mmHg and/or diastolic higher than 120 mmHg (requires immediate medical attention)

If your blood pressure is consistently high, your doctor may diagnose you with hypertension. If it's consistently very low (hypotension), especially if it causes symptoms like dizziness or fainting, you should consult your doctor.

Why is Checking Blood Pressure Important?

Regularly checking your blood pressure is vital because hypertension often has no symptoms, yet it significantly increases the risk of serious health problems such as heart attack, stroke, heart failure, kidney disease, and vision loss. Early detection and management of high blood pressure can help prevent these complications.

Conversely, severely low blood pressure can lead to insufficient blood flow to vital organs, causing symptoms like dizziness, fainting, nausea, blurred vision, and fatigue, and may indicate an underlying medical condition that needs treatment.