Intervals for Cardio


Karvonen Formula

If you want a more personalized and accurate Target Heart Rate Zone (THRZ) you can opt to use the Karvonen Formula to calculate your THRZ.  The standard formula for calculating Maximum Heart Rate does not take into account for individual differences in Resting Heart Rate whereas The Karvonen Formula does.

To find your THRZ using the Karvonen Formula you need to determine your Maximum Heart Rate (Max HR), Resting Heart Rate (Resting HR), and Heart Rate Reserve (HR Reserve).  The HR Reserve is simply the difference between Max HR and Resting HR.  The Resting HR is simply your heart rate at rest measured in pulse beats per minute.  To determine your Resting HR you will need to take your pulse.

The calculations for the Karvonen Formula variables are shown below:

Max HR = 220 - your age     |     Or you can use 206.9 - (0.67 x age)
Resting HR = Your heart rate at rest
HR Reserve = Max HR - Resting HR

The formula for the Karvonen Formula is show below.

Karvonen Formula = (HR Reserve x Training%) + Resting HR

So if you are 30 years old with a Resting HR of 72 beats per minute, 50%-85% of your THRZ using the Karvonen Formula would be 131 to 172 beats per minute (bpm).


Max HR = 190
Resting HR = 72
HR Reserve = 118

50% of THRZ using the Karvonen Formula is (118 X .50) + 72 = 131 bpm
85% of THRZ zone using the Karvonen Formula is (118 X .85) + 72 = 172 bpm

You'll notice that the Karvonen formula will typically calculate a higher target heart rate than the standard formula.  This is because it makes the adjustment for the Resting HR.