The Karvonen Formula
Calculate personalized heart rate training zones using your heart rate reserve.
The Karvonen formula is named after Martti Karvonen, a Finnish physiologist who published his landmark research in 1957. His study demonstrated that calculating training intensity using an individual's heart rate reserve (HRR) — rather than a simple percentage of maximum heart rate — produced more effective improvements in cardiovascular fitness. This insight transformed how coaches and athletes design training zones worldwide.
The Formula
Target HR = ((Max HR − Resting HR) × % Intensity) + Resting HR
How to Calculate
- Determine your Maximum Heart Rate (Max HR). A common estimate is 220 minus your age.
- Measure your Resting Heart Rate (Resting HR). Take your pulse first thing in the morning.
- Calculate your Heart Rate Reserve (HRR): HRR = Max HR − Resting HR.
- Choose a target intensity percentage (e.g., 70% for aerobic base training).
- Multiply HRR by the intensity percentage.
- Add Resting HR to the result to get your target training heart rate.
Why It Matters
Unlike simpler maximum heart rate percentage methods, the Karvonen formula accounts for your individual fitness level through the resting heart rate component. A fitter runner with a low resting heart rate will have different — and more appropriate — training zones than a beginner with the same maximum heart rate. This makes the formula more accurate and personalized.
As your fitness improves and your resting heart rate decreases, your Karvonen-based training zones will shift accordingly, automatically reflecting your progress.