In one sense the maximum heart rate could be defined as the number of times a heart can safely beat in one minute. This is variable and beside the point since most people would determine this rate in a different way. Instead, maximum heart rate and target heart rate are often used synonymously. They mean the highest rate at which a heart should beat in a minute when people are engaged in exercise. Additionally, people are told to exercise at a percentage of the maximum rate instead of at a maximum rate.

There are a variety of formulas that help to determine maximum heart rate, and there is significant dispute on which formula is most correct. Less in contention is the idea that people who have not exercised recently, particularly if they’re at a certain age, should get doctor’s advice before beginning an exercise plan. This typically applies to most people 40 or older, to those who have any other medical conditions, and to anyone who is severely overweight and/or has a family history of heart problems.

Nevertheless, the basic formula that could be used to derive maximum heart rate is age multiplied by .0685 and subtracted from 205.8. There are variations on this including age times .075 subtracted from 220. Doctors may more precisely measure suggested maximum heart by having people undergo cardiac tests like a stress echo, stress test or exercise test.

While maximum heart rate and target heart rate are sometimes used interchangeably, there are some important differences to observe. First, people are rarely supposed to be exercising at their maximum. It is not a target at which to aim, instead people should usually exercise at a percentage of their maximum rate, and in beginning workouts this might not be that much higher than a normal resting heart rate. The goal is to gradually work up, but to stay below maximum until otherwise advised.

Another thing to point out is that these figures may vary by the day. The very simple formulas aren’t specific enough. As much as people may pay attention to heart rate, it’s important to listen to a body’s cues in other ways. The day a person has a cold and exercises, lower than maximum percentage is probably adequate. Feeling out of breath, dizzy or sick to the stomach are probably the body’s suggestion that too much work is being performed. No matter what the heart says, the body’s language is also valuable to interpret so that enough exercise is achieved without overdoing it.