Karvonen HR training zones

Background

When training in activities like running or cycling, the concept of training "zones" is often used, in order to prescribe different levels of intensity.

There is value in training at different levels of intensity (low, moderate, aerobic, unaerobic etc), depending on what an athlete wants to achieve in a specific training session or longer term.

The general method

There are different ways of figuring out these zones. The most popular one, often also used by fitness programs and apps, relies on knowing one's maximum heart rate and with each zone being a percentage of it.

E.g. for someone with a max heart rate of 185bpm, training at 70% intensity would simply be:

185 * 0.7 = 129.5

This doesn't always work

Even when we have the max heart rate figured out, for some people these zones don't seem to correspond to how they actually experience different levels of intensity.

This may be due to them being highly trained athletes, well adapted to higher levels of intensity, or just regular physiological differences among individuals.

In my case, even at my fittest, I could never achieve the expected low intensity zones calculated with this method – my heart rate would always shoot past them at the slightest effort, even though I could sustain that effort almost indefinitely. What gives?

Alternative: the Karvonen method

The Karvonen method is an alternative, only slightly more elaborate method of calculating training zones.

This method calculates percentages based on heart rate reserve. In other words, takes both the max heart rate and the resting heart rate into account.

The full formula is defined as:

((Maximum HR – Resting HR) * Intensity) + Resting HR

So for someone with 185bpm max and 62bpm resting heart rate, to train at 70% intensity, we would have:

((185 - 62) * 0.7) + 62 = 148

This yields a very different result from the general method above (almost 20bmp more for the same intensity)!

While this is again a formula that can be imprecise, it seems to have worked well for me, providing much more realistic ranges that I can follow ✨ If you haven't stumbled upon it and you are frustrated with the default zones provided by your fitness app, it could be worth a try!

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