The maximum heart rate is considered to be the greatest number of beats per minute (bpm) that is safe for an individual, or the highest pulse rate that can be attained during exercise. The simplest way to calculate maximum heart rate is by subtracting the individual’s age from 220. For example, to calculate the maximum heart rate for a 20-year-old, subtract 20 from 200 to get a maximum heart rate of 200 bpm. This formula was devised by Drs. Fox and Haskell in the 1970s and gained popularity when the company Polar Electro used it in its heart rate monitors.
Estimated maximum heart rates (HRmax) can vary significantly depending on the physical fitness of the individual being tested. There have been many studies into the best and most accurate methods to calculate maximum heart rate. Some researchers have found that the maximum heart rate varies with age, but do not believe that it is as simple as subtracting the person’s age from 220.Instead of using this simple calculation, they have developed different formulas based on their research. For instance, scientists at Liverpool John Moores University in England determined that different formulas should be used for males and females when determining maximum heart rate.
While there are several formulas used to calculate maximum heart rate, the most accurate way to measure it is by performing a cardiac stress test. A cardiac stress test involves an individual performing exercise, such as walking or jogging on a treadmill or climbing stairs, while continuously being monitored with an electrocardiogram (EKG). Typically lasting 10 to 20 minutes, the EKG probes measure the actual heart rate until changes in the heart function occur. When this happens, the maximum heart rate has been achieved and the individual is directed to stop.
The calculated maximum heart rate will give an estimated bpm as each individual’s maximum heart rate will have a wide variance depending on age, physiology and fitness level. For example, a marathon runner and a sprinter that are the same age may have a calculated maximum heart rate of 180 bpm (220 – age) using the general formula. If their actual HRmax were measured on using an EKG and cardiac stress test, it may be 20 bpm apart. The sprinter’s rate may be higher due to the type of training, short bursts of high intensity exercise, versus the endurance runner’s longer durations of steady running.
Some factors that may affect the maximum heart rate are the type of work performed, the current fitness level, the type of exercises performed and the environment. To calculate maximum heart rate, it is important to be in good health and free of injury or other medical abnormalities. Remember when starting an exercise regime to do so under the guidance of a physician. This is particularly important if the individual is over 50 years of age and if there are any other underlying conditions.