%Max HR vs Karvonen Zones
Two ways to set your training zones. One is quick and rough. The other accounts for your fitness by using resting heart rate.
%HRmax
Sets zones as straight percentages of your maximum heart rate. Simple, fast, and good enough for general use.
Karvonen (HRR)
Uses heart rate reserve, the gap between max and resting HR, to produce more individualized, fitness-aware zones.
At a glance
| %HRmax | Karvonen (HRR) | |
|---|---|---|
| Inputs needed | Max HR only | Max HR and resting HR |
| Core formula | Target = % × HRmax | Target = % × (HRmax − HRrest) + HRrest |
| Accounts for fitness | No | Yes, via resting HR |
| Zone values (same person) | Lower target HR for a given % | Higher target HR for the same % |
| Ease of use | Very easy, mental math | One extra step, needs resting HR |
| Best for | Beginners, quick estimates, casual training | Trained athletes, endurance zone work |
| Sensitivity to data error | Only HRmax error | HRmax and HRrest error both matter |
Pick %HRmax
Pick %HRmax when you want a fast, no-fuss estimate and you do not have a reliable resting heart rate to hand. It is perfectly adequate for general cardio, beginners, and anyone who just wants a ballpark 'easy / moderate / hard' guide. The math is simple enough to do in your head mid-workout.
Pick Karvonen (HRR)
Pick Karvonen when precision matters, particularly for structured endurance training. Because it factors in your resting heart rate, it personalizes zones to your actual fitness, which is why two people with the same max HR get different targets. If you have a trustworthy resting HR (measured first thing in the morning), Karvonen is the better tool.
The simple method: %HRmax
The %HRmax method does exactly what it sounds like: it takes your estimated maximum heart rate and slices it into percentage bands. A common scheme runs roughly 50-60% for very easy work up to 90-100% for maximal efforts, with the aerobic 'fat-burning' and tempo zones sitting in between.
Its appeal is speed and simplicity. You only need one number, your max HR (often estimated as 220 minus age, or better, a more refined formula or a real field test), and the math is trivial. The trade-off is that it ignores how fit you are. Two people who share a max HR get identical zones even if one is an untrained beginner and the other a seasoned runner, which is not how their bodies actually respond.
The individualized method: Karvonen
The Karvonen formula fixes that blind spot by building zones on your heart rate reserve (HRR), the distance between your maximum and resting heart rates. The formula is target HR = intensity% × (HRmax − HRrest) + HRrest.
That resting-HR term is the key. A fitter person typically has a lower resting heart rate, which widens their reserve and shifts their zones, so Karvonen personalizes the target to the individual rather than treating everyone with the same max identically. The cost is that you need a trustworthy resting heart rate and one extra calculation, and any error in either input flows into the result.
Worked example: same max, different targets
Take two people, both with a max HR of 190, training at 70% intensity.
By %HRmax, the target is simply 0.70 × 190 = 133 bpm for both of them.
Now apply Karvonen. Person A is unfit with a resting HR of 75: 0.70 × (190 − 75) + 75 = 155 bpm. Person B is well-trained with a resting HR of 50: 0.70 × (190 − 50) + 50 = 148 bpm.
Notice two things. Karvonen's targets sit higher than the flat %HRmax figure at the same percentage, and the two people get different numbers despite sharing a max HR. That difference, driven entirely by resting heart rate, is the whole reason endurance athletes favor Karvonen for dialing in zones.
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General educational information, not medical advice.