The human heart creates a pressure within the circulatory system every time it beats. This pressure pushes blood through the body so the tissues and organs can receive the oxygen they need. Some people experience periods where their blood pressure is too high or too low. When blood pressure is outside of its normal range, serious physiological issues can follow. Keeping our blood pressure at a normal level is an important part of keeping our bodies functioning properly.
When measuring blood pressure, the machine or doctor will report two numbers. The top number is systolic blood pressure -- it represents the pressure in the blood vessels when the heart beats. The bottom number is diastolic blood pressure, the pressure in between beats when the heart is resting. The mm Hg measurement stands for millimeters of mercury. The first accurate pressure gauges used mercury, but the unit of measure remained even when mercury fell out of use.
This site offers information designed for educational purposes only. You should not rely on any information on this site as a substitute for professional medical advice, diagnosis, treatment, or as a substitute for, professional counseling care, advice, diagnosis, or treatment. If you have any concerns or questions about your health, you should always consult with a physician or other health-care professional.