Reading Your Blood Pressure Numbers

If you check your blood pressure at home, you already see two numbers every time. Here's what they mean, and how to know if yours are in a healthy range.

Systolic vs. diastolic

The top number, systolic pressure, measures the force in your arteries when your heart beats. The bottom number, diastolic pressure, measures the pressure between beats, when your heart is resting. A reading of "120 over 80" means a systolic of 120 and a diastolic of 80.

General ranges

As a general guide: below 120/80 is considered normal, 120–129/under 80 is elevated, and 130/80 or higher is generally considered high blood pressure — though your doctor will interpret your numbers in the context of your overall health, age, and history.

Getting an accurate reading at home

Sit quietly for five minutes before measuring, keep your feet flat on the floor, support your arm at heart level, and avoid caffeine or exercise in the 30 minutes beforehand. Take two readings a minute or two apart and record both — a single number can be misleading.

"White coat" readings

Some people have higher readings at the doctor's office than at home, simply due to nerves. If this sounds familiar, home monitoring over a week or two often gives a more accurate picture.

When to call your doctor

A single high reading usually isn't an emergency, but consistently elevated numbers, or a reading above 180/120 accompanied by symptoms like chest pain or vision changes, warrants prompt medical attention.