How to Calculate Training Zone Heart Rate and Maximum Heart Rate

To get the most out of aerobic exercise, you must workout at a 60% to 85% intensity level, where intensity level is defined by heart rate. When you are exercising at a 60% to 85% intensity level, your heart rate is within what is called the "training zone." To calculate upper end and lower end of your training zone heart rate, you need three pieces of information: your maximum heart rate (MHR), which corresponds to a 100% intensity level; your resting heart rate (RHR), which corresponds to a 0% intensity level, and a special equation called the Karvonen Formula.

Step 1: Estimate your maximum heart rate using the equation

MHR = 208 - (0.7)A,

where "A" is your age, in years. The only way to know your true maximum heart rate is to undergo a cardiac stress test at a laboratory. However, this equation gives a useful, and fairly accurate estimate of maximum heart rate. It is the formula programmed into the calculator on the left.

As a side note, there are other equations for estimating maximum heart rate based on age. The most common alternative formula is

MHR = 220 - A.

Step 2: Determine your resting heart rate. When you wake up in the morning, count your pulse for 15 seconds and multiply by 4 to find the beats per minute. (Alternatively, count for 20 seconds and multiply by 3)

Step 3: Now, use the Karvonen Formula to determine your training zone heart rate. The training zone is a range that tells you how fast your heart should beat when you are working-out at a 60% to 85% intensity level. The upper and lower ends are given by the equations

Upper End = (0.85)MHR + (0.15)RHR
Lower End = (0.60)MHR + (0.40)RHR

Incidentally, you can calculate the target heart rate for an arbitrary intensity level "i" (expressed as a decimal) by using this formula:

(i)MHR + (1-i)RHR.

For instance, the heart rate for a 72% intensity level is

(0.72)MHR + (0.28)RHR.

Example: Suppose a person is 30 years old and has a resting heart rate of 60 bpm. Then his MHR is

208 - (0.7)30 = 187 bpm,

and the upper and lower ends of his training zone heart rate are

(0.85)(187) + (0.15)(60) = 168 bpm
(0.60)(187) + (0.40)(60) = 136 bpm.

© Had2Know 2010