The Karvonen Formula
The Karvonen formula is the gold standard for calculating personalized heart rate training zones. Unlike simpler methods that only use maximum heart rate, it factors in your resting heart rate to deliver zones that truly reflect your fitness level.
Named after Finnish physiologist Martti Karvonen, this formula was published in 1957 in his study 'The Effects of Training on Heart Rate.' His groundbreaking insight was that training intensity should be based on Heart Rate Reserve — the difference between maximum and resting heart rate — rather than maximum heart rate alone. This approach accounts for individual fitness differences, making training zones far more personalized and effective. Today, the Karvonen method remains the preferred approach among coaches and exercise physiologists worldwide.
Target HR =
((Max HR − Resting HR) × Intensity%) + Resting HR
How to Calculate
1
Determine your Maximum Heart Rate (Max HR). The simplest estimate: 220 − your age.
2
Measure your Resting Heart Rate (Resting HR) first thing in the morning.
3
Calculate Heart Rate Reserve (HRR) = Max HR − Resting HR.
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Age
30
Max HR
190
Resting HR
60
Intensity
70%
Target HR
151 bpm
(190 − 60) × 0.70 + 60 = 151 bpm. This runner should aim for 151 bpm during aerobic endurance workouts — a zone that accounts for their trained, low resting heart rate.
Two runners can share the same max heart rate of 190 bpm but have very different fitness levels. A trained runner with a resting HR of 50 has an HRR of 140, while a beginner at 80 bpm resting has only 110. At 70% intensity, the Karvonen formula gives them different target zones (148 vs 157 bpm), reflecting their actual fitness. Simple %MaxHR (133 bpm for both) ignores this critical difference entirely.
Heart Rate Training Zones
Zone 1 — Recovery
50–60% HRR
Very light effort. Active recovery, warm-ups, and cool-downs. Promotes blood flow without adding training stress.
Zone 2 — Aerobic Base
60–70% HRR
Conversational pace. Builds aerobic foundation, improves fat metabolism. The majority of easy runs should be here.
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FAQ
Q. How accurate is '220 − age' for Max HR?
It's a rough estimate with a standard deviation of ±10-12 bpm. For more accuracy, do a field test: run a hard uphill interval 3-4 times and note the highest reading on your HR monitor. Lab testing is the gold standard.
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Calculate Your Heart Rate Zones
Enter your max HR and resting HR to get personalized training zones using the Karvonen formula.