You shouldn't ignore the bottom number on your blood pressure reading. That's the message from a recent study published in the New England Journal of Medicine. When uncontrolled, both the bottom and top numbers can increase your risk of heart attack and stroke.

One in three American adults has high blood pressure, according to the American Heart Association. Fortunately, high blood pressure, also called hypertension, can be detected easily through a common test conducted during a visit with your healthcare provider.

In this Mayo Clinic Minute, Dr. Brian Shapiro, a Mayo Clinic cardiologist, discusses an optimal blood pressure reading and offers ideas for getting your blood pressure to that mark.

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"Basically, blood pressure is the key to life," says Dr. Shapiro. And he says the key with blood pressure is keeping it from getting too high and avoiding a condition called hypertension. "Some of the newer data that has emerged and will continue to emerge over the next couple of years is going to suggest that lower is better," says Dr. Shapiro.

Blood pressure is recorded as two numbers. The upper number, the systolic blood pressure, measures force on artery walls when the heart beats. The bottom number, the diastolic blood pressure, measures force when the heart relaxes. The American Heart Association says an optimal blood pressure is less than 120 over 80.

If your blood pressure is high, Dr. Shapiro says diet and lifestyle changes may bring it down. "(Examples would be) reducing salt, less going out to eat, less alcohol consumption, more physical activity, and more exercise," says Dr. Shapiro.

If you're hypertensive after these changes, your doctor may recommend medication and remind you about what's at stake. "If you want to live a long time, you've got to keep your blood pressure low," says Dr. Shapiro.