Matt Fitzgerald—A heart rate monitor can be a useful piece of training equipment. Heart rate is a reliable indicator of exercise intensity, so training with one can help you work hard enough—but not too hard—in each workout. But using this type of device will not automatically make your training more effective. As with any piece of equipment, there is a right way to use a heart rate monitor, and there are numerous possible mistakes you can make with it.
There are three mistakes in the use of heart rate monitors that are especially common. Avoid these and you will be well on your way toward getting the most out of your device.
Mistake #1: Using The 220-Age Formula
Effective training requires that you perform different types of workouts at various intensities, from low-intensity recovery workouts to high-intensity speed intervals. A heart rate monitor can help you perform each type of workout at the proper intensity by assigning a specific target heart rate or heart rate zone to each. But this only works if the targets or zones are customized to your individual heart rate profile.
When heart rate-based training became popular in the mid-1980s, athletes were instructed to subtract their age from 220 to determine their approximate maximum heart rate, and to perform different types of workouts at different percentages of their maximum heart rate. However, this formula is arbitrary and does not generate appropriate target heart rates for most athletes.
A much better way to determine appropriate target heart rates is to perform a 30-minute simulated race and use your average heart rate for this effort as your “anaerobic threshold” heart rate. This becomes your target heart rate for threshold workouts. Most of your workouts should be done at lower heart rates. Once a week or so, perform an interval workout at a higher target heart rate.
Mistake #2: Using an HR Monitor in Speed Workouts
Heart rate monitors are not useful in high-intensity interval workouts featuring individual efforts lasting one minute or less. That’s because of a phenomenon called cardiac lag. When you suddenly increase your exercise intensity, it takes a while for your heart rate to climb to the level at which it will ultimately plateau. Therefore, in short, fast intervals, you may find your heart rate climbing most or all the way through each. In this type of workout, it’s best to use pace and perceived effort to regulate your intensity.
Mistake #3: Over-Interpreting HR Data
If you train regularly with a heart rate monitor, it is important to keep in mind that heart rate has significant limitations as an indicator of exercise intensity. There are many other physiological factors involved as well. An easy way to see this is to compare heart rates in outdoor versus treadmill running. Most runners have a lower heart rate when running on a treadmill than they do running outdoors at the same pace. You might think this means that running on a treadmill is easier, and that you can run faster on a treadmill. In fact, just the opposite is true. Studies have shown that runners feel better and can run faster outdoors, even though their heart rates are higher. Why? Because heart rate does not tell the whole story of exercise intensity.
Athletes who assume heart rate does tell the whole story often encounter problems where there really are none. They find themselves asking questions like, “Why can’t I get my heart rate up on the bike like I do when running?” and, “Why is my heart rate always higher than my friend’s even though we have the same race times?”
These are not real problems. The only real problems in training are 1) performing poorly and 2) feeling bad. If you’re performing to expectations and feeling good, or at least normal, then nothing your heart rate monitor tells you is bad.