Heart rate monitors are popular among runners and other endurance athletes. Before spending money on the equipment and time learning how to use it, you should first understand what a heart monitor is capable of doing and how it can be used as a training tool.
A heart rate monitor simply measures the rate of your heartbeat (fast or slow), but not your heart rhythm (regular or irregular). Therefore, it should not be used as a safety measure for runners with known or suspected heart conditions.
Since your heart rate is a reflection of how hard your body is working, heart rate monitors are often used by runners and coaches to guide training. Without a heart rate monitor, training goals are set based on speed, distance, and/or perceived exertion. Using a heart rate monitor, runners are able to set training goals based on their heart rate. Doing this can encourage you to give more effort during hard runs, and conversely, it can remind you to put the brakes on your easy runs.
Training programs that use heart rate monitors are designed based on percentages of a runner’s maximum heart rate. The most common method of estimating a maximum heart rate is to subtract your age from the number 220; e.g., an estimated maximum heart rate for a 35-year-old with no known medical problems is 185. Then, a training program is created with goals such as 50–60 percent of maximum heart rate for easy runs, 60–70 percent for immediate runs, and 70–80 percent for more intense runs.
You should also be aware of the limitations of using a heart rate monitor for training. First, there is no perfect equation for estimating a maximum heart rate, and your heart rate for maximal effort during one activity is different than it is during another. Second, many factors affect your heart rate from day to day, which can make using this training method challenging. Examples include hydration status, body temperature, sleep, and stress.
Dr. Brett Toresdahl is a Sports Medicine Physician at Hospital for Special Surgery. His research focus has been in the prevention and treatment of sudden cardiac arrest in young athletes. He enjoys staying active outdoors with his family with snowboarding, biking, running, and hiking.