Find your training heart rate zones based on estimated maximum heart rate.
Estimated max HR = 220 − age. Zones are expressed as a percentage range of this estimated maximum.
For general wellness information only — not medical advice. Consult a healthcare professional for personal guidance.
The famous "220 minus age" formula for max heart rate was never derived from a rigorous scientific study — it originated as a rough approximation decades ago and stuck in fitness culture largely by accident, with a real standard deviation of around ±10-12 beats per minute between individuals of the same age. That means for any given 40-year-old, their true max heart rate could genuinely sit anywhere from the high 160s to the low 190s, even though the formula confidently predicts exactly 180. Newer formulas like Tanaka (208 − 0.7×age) tend to track actual measured max heart rate more closely, especially for older adults, where 220-minus-age tends to be least accurate.
A bigger issue than which max-HR formula you use is that simple percentage-of-max zones (like "Zone 2 = 60-70% of max HR") ignore your resting heart rate entirely, treating a very fit person with a resting HR of 45 the same as an unfit person with a resting HR of 80. The Karvonen formula corrects this by working from heart rate reserve — the gap between your resting and maximum heart rate — so your training zones are calculated relative to your own cardiovascular fitness, not just your age. Two people the same age can end up with meaningfully different, more personally accurate target zones under Karvonen than under a flat age-based percentage method.
It's a rough population average, not an individually validated number — actual max heart rate varies by roughly ±10-12 beats per minute from the formula's prediction for people of the same age. It was never derived from a rigorous study; it became standard mostly by convention rather than precision.
The Karvonen formula calculates training zones from your heart rate reserve — the difference between your resting and maximum heart rate — rather than a flat percentage of max HR alone. This accounts for your individual fitness level, since a very fit person with a low resting heart rate gets meaningfully different (usually higher) target zones than an unfit person of the same age.
Research suggests the Tanaka formula (208 − 0.7×age) and the similar Gulati/Gellish formulas track measured max heart rate more accurately than 220-minus-age, particularly for older adults, where the traditional formula tends to be least reliable.
Yes — that's the input that makes Karvonen more personalized than a simple age-based percentage method. Measure your resting heart rate first thing in the morning, before getting out of bed, over a few days for a reliable average, then use that figure alongside your estimated max heart rate.