Many exercise programs and tests used to measure heart function are based on an unreliable MAXIMUM HEART RATE formula that predicts the fastest your heart can beat and still pump blood through your body. Although this formula is the gold standard used today, it is not based on science.
Dr. Sam Fox is one of the most respected heart specialists in the world. In the 1960s, he was very helpful to me when I was competing, planning and setting up running programs. In 1970 he was the director of the United States Public Health Service Program to Prevent heart disease. 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 noticed that maximum heart rate appeared to equal to 220 minus a person’s age. They reported this observation, and for the last 40 years, the formula has been taught in physical education courses and used to test heart function and athletic fitness. The whole concept of maximum heart rate and the formula that it is equal to 220 minus your age is flawed.
The formula is wrong because your legs drive your heart rate; 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,taught to doctors 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 study of 43 different formulae for maximum Heart Rate concluded that 1) ” No “acceptable” formula currently existed”. 2) The formula that fit age better than others is: HRmax = 205.8 – (0.685 x age). It has a standard deviation that is 6.4 beats per minute which is very large (1).
A study from Liverpool, England shows that the maximum heart rate for athletes is lower than for aged-matched sedentary people. The maximum heart rate of male athletes was calculated to be 202 – (0.55 x age), and for female athletes, 216 – (1.09 x age). Both weight lifters and runners had similar maximum heart rates, which were significantly lower than the age-matched sedentary people. The athletes have hearts that can pump more blood with each beat than the hearts of sedentary people, so they do not beat as often (2).
Another study from Oakland University in Rochester, Michigan showed that the standard MHR formula overestimated the maximum heart rate for younger exercisers and underestimated the maximum rate for older ones (3).
All MHR formulae are based on averages. They can be used to help you plan and monitor your exercise program, but should not be interpreted as absolute limits or goals. If you want to train to become fast, use the following: Three times a week, never on consecutive days, either race or push the pace so that you are at your anaerobic threshold and then use bursts to exceed it to become short of breath. On the other four days, take it easy and do not put pressure on your muscles. The standard Maximum Heart Rate formula (MHR = 220 – age) does not apply to highly fit athletes.
1) Robergs R and Landwehr R., “The Surprising History of the “HRmax=220-age” Equation”. Journal of Exercise Physiology, 2002;5 (2): 1-10
2) International Journal of Sports Medicine, January 2008
3) Medicine and Science in Sports and Exercise, May 2007