# Heart Rate (Karvonen Method)

According to modern-day fitness experts in order to achieve the many benefits of exercise, you should maintain a certain level of exercise called the “training zone”. The Master Physicians already make mention of this concept: “One should begin exercising slowly, increasing [the pace] until he reaches the optimum level of exercise.”

The most accurate method for measuring your personal training zone is by calculating your maximum heart rate (Karvonen Method). Although this formula seems somewhat complex, all you need to input below is your 1) Age and 2) Resting Heart Rate (See how to measure your resting heart rate in the footnotes below).

All you need to add to the calculator below is your age (What is Your Age?) and RHR (Resting Heart Rate taken Manually). Input these two numbers and click enter. Our calculator does the rest and your Heart Rate Reserve (Karvonen Method) will be automatically calculated in the bottom shaded area for Moderate and Vigorous Exercise. Amazingly, after searching the internet, this seems to be the only accurate calculator, taking all the most up to date parameters and formula’s into account:

The most accurate method for measuring your personal training zone is by calculating your maximum heart rate.

Average resting pulse is 65 to 85 beats per minute.[i]

When you exercise, your heart rate increases. Your training zone is a certain percentage of your maximum heart rate.

While ACSM (American College of Sports Medicine) still utilizes % Maximal Heart Rate (MHR) for intensity, they no longer recommend the use of 220 minus age (Fox and Haskell formula) to calculate it. [ii]

ACSM recommends more accurate formulas for MHR: Tanaka formula: 208 – (0.7 * age) .

In order to calculate your minimum heart rate, the Heart Rate Reserve (Karvonen Method) is most accurate because it takes different resting heart rates into account.[iii]

The theory you should know (but you can use our calculator above which makes it quick and simple):

HRR = (Maximum Heart Rate – Resting Heart Rate) * % intensity)) + RHR

(Remember to add the Resting Heart Rate into the equation even though you have already in order to calculate the HRR.)

What is the % intensity in the equation?

For moderate exercise, your heart must beat at 50 to 60 percent of HRR (or 60 -75% of MHR).

For vigorous exercise, your heart must beat at > 60 percent of HRR.

So for example, a thirty year old:

o   MHR = 187 (Tanaka Formula)

o   RHR = 65 (manually measured or with portable electronic machine)

o   HRR (MHR – RHR) = 122 HRR

o   122 * 60% intensity = 73.2

o   Now add the RHR back in, so 73.2 + 65 = 138.2 beats per minute.

This would be the minimum heart rate for vigorous exercise according to the Karvonen Method.

[i] How do you measure your heart rate? It’s pretty simple. Just feel your pulse on your wrist or at the side of your windpipe, as soon as you stop exercising. Do not use your thumb to feel your pulse. To determine the number of heartbeats per minute, take your pulse for fifteen seconds and multiply by four. Count the first pulse beat as zero at the start of the time interval. You must do it at this stage because the heartbeat slows down dramatically within the first minute after exercise. Another option is inexpensive electronic compact machines that measure both heart rate and blood pressure.
[ii]The formula of ‘220-age’ was introduced in 1970 and was widely accepted by the health and fitness community. However, recently its validity has been questioned. The subjects used in the study to determine the formula were not representative of the general population. Standard deviations of 10 -20 beats per minutes have been observed.

[iii]Let us see why: Compare % MHR estimations with different resting heart rates (RHR). For example, let us say that Tom has an MHR of 200 and Sam has the same maximum heart rate. However, Tom has a resting heart rate of 50 and Sam has a RHR of 85. 70% of both their MHR is 140. Now if you minus their different RHR, you will see that Tom has a margin of increase of 90 (140 – 50) and Sam 55 (140 – 85). There is a difference of 45 beats between them. However, if one uses the % HRR, which takes the resting heart rate into account when calculating the formula, the difference is only 21. (Tom, HRR = 200 (MHR) – 50 (RHR) = 150; 60% HRR = 90; 90 + 50 = 140 / Sam, HRR = 200 (MHR) – 85 (RHR) = 115; 60% HRR = 69; 69 + 50 = 119). That’s a significant difference as the HRR formula reduces the discrepancies in training intensities between individuals with different RHR. It also accommodates training adaptations that increase HRR, attributed to a reduced RHR.