Blood pressure is the force exerted by the blood on the walls of the the blood vessels it travels through. Each time the heart beats, it exerts a maximum pressure, called a systolic pressure, and also has a minimum pressure, called the diastolic pressure. Blood pressure is greatest as it is leaving the heart, then decreases rapidly as it moves through the network of blood vessels.
Resting blood pressure would refer to the blood pressure of a person at rest, not exerting physical activity such as exercise, which would tend to raise the heart rate and influence the blood pressure. Normal blood pressure readings for adults range from 110 to 140 millimeters of mercury for the systolic reading, and 70 to 90 millimeters of mercury for the diastolic reading.
Blood pressure is typically measured by securing an inflatable elastic band, called a cuff, around a person's upper arm. A stethoscope is required to listen for the flow of the blood in the person's arm. As the cuff is inflated, the blood flow is momentarily stopped. The air pressure is slowly released, and the number that is observed when blood starts flowing again is noted. The pressure is slowly released while listening for the blood pulsing through the person's veins. At the point where no more pulse can be detected, that number is recorded. The first number is the systolic reading, while the second number is the diastolic reading.