Target Heart Rate

In order to become aerobically fit, the American Heart Association recommends exercising for 30 to 60 minutes 3 to 4 times per week. To receive the maximum benefits from your exercise, you should exercise within what is called the target heart rate zone. Individuals who are sedentary or who have been exercising regularly for less than six months, are considered beginners or intermediates. To calculate your target heart rate (THR) in this category, use the formula:

THR = MHR x PEI

where MHR is your maximum heart rate and PEI is the percent of your exercise intensity. Your maximum heart rate can be calculated by taking 220 minus your age. Calculate your maximum heart rate and plug it into the formula above. For your maximum heart rate, graph the equation where PEI is the independent variable written as a decimal ranging from 0 to 1. If your target heart zone is for workouts where the percent exercise intensity ranges from 60% to 80%, what is your minimum target heart rate and your maximum target heart rate? Indicate the target heart zone on your graph.

Individuals who have been exercising for at least six months on a regular basis are considered advanced and calculate their target heart rate differently. For this category, use the formula

THR = [(MHR - RHR) x PEI] + RHR

where RHR is your resting heart rate. Calculate your resting heart rate by measuring your heart rate for one minute for three mornings before rising out of bed and taking the average of your measured heart rates. Plug in your MHR and RHR into the formula above, and graph this new equation where PEI is the independent variable written as a decimal ranging from 0 to 1. The target heart rate zone is still for workouts where the percent exercise intensity ranges from 60% to 80%. What is your minimum target heart rate using this equation and what is your maximum target heart rate? How do these compare with the minimum and maximum you found using the formula for beginners and intermediates? Which do you think is more accurate for you?

Now assume that your resting heart rate stays the same over the next ten years and that you always exercise at a 70% intensity. Plug your RHR, PEI and the formula for MHR into

THR = [(MHR - RHR) x PEI] + RHR

and simplify this equation. Graph the simplified equation where your age is the independent variable and ranges from your current age to 10 years past your current age. What does this graph tell you about your target heart rate as you get older?