Many of the standard tests used to measure heart function and fitness are based on a MAXIMUM HEART RATE formula, that predicts the fastest your heart can beat and still pump blood through your body. Although this formula is the golden standard used today, it is not based on science.
In 1970, a good friend, Sam Fox, was the director of the United States Public Health Service Program to Prevent heart disease. He is one of the most respected heart specialists in the world. He and a young researcher named William Haskell were flying to a meeting. They put together several studies comparing maximum heart rate and age. Sam Fox took out a pencil and plotted a graph of age verses maximum heart rate and said it looks like maximum heart rate is equal to 220 minus a person's age. For the last 30 years, this formula has been taught in physical education and heart function course and has been used to test heart function and athletic fitness. In the 1960s, Sam Fox was very helpful to me when I was competing, planning and setting up running programs, but the whole concept of maximum heart rate and the formula that it is equal to 220 minus your age is ridiculous.
The formula is wrong because your legs drive your heart. Your heart does not drive your legs. Maximum heart rate depends on the strength of your legs, not the strength of your heart. When you contract your leg muscles, they squeeze against the blood vessels near them to pump blood from your leg veins toward your heart. When your leg muscle relax, your leg veins fill with blood. So your leg muscles pump increased amounts of blood toward your heart. This increased blood fills the heart and causes your heart to be faster and with more force. This is called the Bainbridge reflex that doctors are taught in their first year of medical school. The stronger your legs are, the more blood they can pump, which causes your heart to beat faster.
A pencil mark plotted on a graph during an airplane flight more than 30 years ago has been the accepted formula for maximum heart rate for more than 30 years and the medical community has accepted this dogma for more than 30 years. How to use a heart rate monitor