Basic heart rate zone charts calculate everything from age alone, but two people the same age can have very different fitness levels — and the Karvonen method accounts for that by factoring in your actual resting heart rate, producing a more personalized target zone than an age-only formula.
Resting heart rate is a reasonable proxy for cardiovascular fitness: a lower resting heart rate generally reflects a more efficient, better-conditioned heart. The Karvonen method uses the gap between your maximum heart rate and your resting heart rate — called heart rate reserve — as the basis for calculating training zones, rather than just applying a flat percentage of max heart rate to everyone regardless of fitness level.
How Target Heart Rate Is Calculated
Heart Rate Reserve = Max Heart Rate (220 − Age) − Resting Heart Rate
Target Heart Rate = (Heart Rate Reserve × Intensity %) + Resting Heart Rate
Moderate intensity is typically targeted at 50-70% of heart rate reserve; vigorous intensity at 70-85%.
A Worked Example
For a 30-year-old with a resting heart rate of 65 bpm: Max HR = 220 − 30 = 190. Heart Rate Reserve = 190 − 65 = 125. Moderate zone (50-70%): (125 × 0.50) + 65 = 127.5 bpm to (125 × 0.70) + 65 = 152.5 bpm. Vigorous zone (70-85%): 152.5 bpm to (125 × 0.85) + 65 = 171.25 bpm — giving clear, personalized heart rate ranges to target during different types of workouts.
Common Mistakes to Avoid
- Using only the simple age-based formula (220 − age) without accounting for resting heart rate: this is a reasonable rough estimate, but Karvonen's inclusion of resting heart rate produces a more personalized, generally more accurate target.
- Not measuring resting heart rate correctly: it's most accurate measured first thing in the morning, before getting out of bed, over a few consecutive days for an average.
- Training exclusively in one zone: effective cardiovascular training typically mixes moderate-zone endurance work with some vigorous-zone intensity work.
- Treating heart rate zones as rigid boundaries: they're useful guides for training intensity, not strict limits that must never be crossed during a workout.
Bottom Line
Your own resting heart rate makes your target zones more accurate than an age-only estimate. Use a Target Heart Rate Calculator with your age and resting heart rate to find personalized moderate and vigorous training zones.