How to Accurately Measure Your Blood Pressure
Your blood pressure indicates how well your blood is circulating. These numbers are an indicator of how much stress is being put on your heart and circulatory system to pump blood through your body. Elevated blood pressure is a known risk factor for heart disease, stroke, and coronary artery disease.1
How to Read Blood Pressure Numbers
Blood pressure readings are measured in mmHg (millimeters of Mercury) and given in the form of two numbers. For example, it might be read as “130 over 70.”
The top number is systolic blood pressure, which indicates how much pressure your blood is putting on artery walls when your heart is beating. The bottom number is diastolic blood pressure, which indicates how much pressure your blood is putting on artery walls between heart beats.
What Do Blood Pressure Numbers Mean?
The American Heart Association categorizes blood pressure into 5 different ranges, as outlined below.2
120/80 or less = normal blood pressure
120-129 over less than 80 = elevated blood pressure
130-139 over 80-89 = hypertension stage 1
120/90 or higher = hypertension stage 2
180/120 for several readings = hypertensive crisis that requires immediate medical attention
Keeping your blood pressure as close to normal as possible is ideal for short- and long-term health outcomes. Eating a healthy diet, exercising regularly, not smoking, maintaining a healthy weight, and managing your stress are good lifestyle habits. It’s also a good idea to get regular heart health checkups.3
Factors That Affect Blood Pressure Accuracy
You can check blood pressure at home using a home monitor. This is an especially important habit if you have high blood pressure. Knowing your numbers can help you manage them, make sure your lifestyle and/or medication are working, and alert you if medical attention is needed.
Some of the factors that can affect blood pressure accuracy include:
- Cuff size, or how well the monitor fits around your arm
- Readability, or how clearly you can read the numbers on the monitor screen
- Time of day, and consistency in the times you measure your numbers
- What you eat and drink prior to taking your blood pressure
- How physically active you have been prior to taking your reading
- Where on your arm you place your blood pressure cuff
Many factors can influence how high or low, or inconsistent, your blood pressure numbers may be, making it important to understand how to take an accurate measurement.
4 Tips For Accurately Measuring Blood Pressure
Here are some best practices to ensure the most accurate blood pressure readings.4
- Be consistent in the frequency and time of day you take measurements. Check your blood pressure first thing in the morning, before eating, drinking, or taking medications, and again at night before bed. Take measurements at the same time every day for accuracy and take a repeat reading each time.
- Avoid caffeine, alcohol, or food for at least 30 minutes before taking a measurement, as these can raise or lower your numbers.
- Sit comfortable and quietly for at least 5 minutes before taking a reading. Stay silent and breathe calmly. Taking your blood pressure too soon after exercising, for instance, can throw off your numbers.
- Make sure your cuff is fitted properly and used consistently. It should be placed on bare arm skin and not over clothing. Your arm should be rested on something at the level of your heart, not extended high or hanging low, like on a chair armrest. Be sure to purchase a cuff that fits properly and is not too tight or too loose.
Monitoring blood pressure at home can be an important practice in preventive health, especially if you’re prone to high measurements. Be sure to incorporate best practices to make sure you’re getting the most accurate readings.
- Int J Hypertens. 2017;2017:5491838.
- Understanding blood pressure readings. American Heart Association.
- Korean J Fam Med. 2017 Jul;38(4):173-180.
- Get the most out of home blood pressure monitoring. Mayo Clinic.
- Blog Contributor