In order to deliver life-giving blood to all of the body's organs and tissues, your heart must contract at a steady rate that provides sufficient time for it to fill between heartbeats, yet allows it to beat frequently enough to meet the body's demand for blood flow. Achieving an ideal ratio that provides frequent enough heartbeats yet allows sufficient time for filling will determine the ideal heart rate.
The Cardiac Cycle
In the normal cardiac cycle, blood fills the heart by returning to receiving chambers, called atria, as it flows back from your body through the veins. A small contraction of your atria then pushes the blood into larger pumping chambers called ventricles. Powerful contractions of the ventricles then force blood out of the heart, through arteries, delivering oxygen and nutrient supplying blood to cells and tissues throughout the body.
Ideal Resting Heart Rate
At rest, when your body's workload is low, the demand for nutrient- and oxygen-carrying blood is low. The heart rate, when measured under this condition, is called the resting heart rate. According to research published in the American Journal of Physiology, the average resting heart rate for adult women is about 65 beats per minute and for males averages 52 beats per minute. Because of variations in age, size and fitness level, a resting heart rate that falls within five or six beats above or below these averages should be considered normal.
Maximum Heart Rate
As you begin to demand more of your body while exercising, the demand for blood flow to your muscles and other organs increases significantly. This requires a elevation of your heart rate which, when exercising at your maximum capacity, is referred to as your maximum heart rate. The common and simple formula to determine your maximum heart rate is to subtract your current age, in years, from the number 220. If you are 25 years old, your maximum heart rate should be 195 beats per minute (220 - 25 = 195).
Heart Rate Recovery
After a strenuous workout when your maximum heart rate has been reached, the time it takes for your elevated heart rate to return to normal -- the heart rate recovery time -- can provide an additional measure of cardiovascular health. Research published in the New England Journal of Medicine shows that a healthy heart rate should decline by at least 12 beats per minute as it returns to its resting rate following exercise.
Measuirng Your Heart Rate
The simplest way to measure your heart rate is by sensing the pulsations of arterial blood flow as it travels through arteries just under the surface of your skin. With each beat of the heart, a pulsation can be found in these superficial arteries. Your pulse rate will therefore reflect and equal your heart rate. The most commonly used sites are at the carotid arteries along the sides of your neck and the radial artery on the inner surface of your wrists.