Health, Physical Education, and Recreation
Calculation of Exercise Heart Rates

The calculation of exercise heart rates using this formula is commonly called the Karvonen method or the Heart Rate Reserve (HRR) method, so if you hear either of these terms remember they both are the same. With this page I would like to walk you through the calculation, show you the formula, then do a sample calculation so you can get some "hands on" experience.

All you need is your age and resting heart rate. In step 1, your age is subtracted from 220 which is the theoretical maximal heart rate for humans. It is age adjusted because our heart rate will slow down by about one beat per year. Keep in mind that formulas only estimate these values (the standard deviation for heart rate is + 11 beats per minute!). In order to obtain a true maximal heart rate (HR_max), a maximal treadmill test should be completed.

Once you have the HR_max, the resting heart rate (RHR) is subtracted from it (step 2) which gives the Heart Rate Reserve (HRR). In order to measure your resting heart rate, it is best to take your pulse either after you've been sitting quietly for 5 - 10 minutes or before you get out of bed in the morning. You can measure either at the wrist (radial pulse), or at the neck (carotid pulse) by counting the number of beats in 30 seconds and multiply by 2.

With improved aerobic fitness the resting heart rate will go down, and this part of the formula helps to account for individual differences in fitness.

Once the HRR has been determined it is mutiplied by the desired training intensity (step 3). The American College of Sports Medicine (ACSM) recommends 60 to 80% of HRR for improvements in cardiorespiratory fitness.

Next, the resting heart rate is added back in, yeilding the Target Heart Rate (THR) for that specific intensity level (step 4 and step 6). That's all there is to it. Here it is in its mathematical format.

1. 220 - age = Age predicted Maximal Heart Rate (HR_max)
2. HR_max - Resting Heart Rate (RHR) = Heart Rate Reserve (HRR)
3. HRR x intensity level 1 (60%) = Quantity 1
4. Quantity 1 + RHR = Lower training range (THR)
5. HRR x intensity level 2 (80%) = Quantity 2
6. Quantity 2 + RHR = Upper training range (THR)

Here is a sample calculation using a 40 year old with a Resting Heart Rate of 72 beats per minute (bpm).

1. 220 - 40 (age) = 180 (HR_max)
2. 180 - 72 (RHR) = 108 (HRR)
3. 108 x 0.60 (60%) = 65
4. 65 + 72 (RHR) = 137 Lower training range (THR)
5. 108 x 0.80 (80%) = 86
6. 86 + 72 (RHR) = 158 Upper training range (THR)

The training range for this person would then be 137 - 158 bpm.