Training by heart rate keeps your effort honest. It starts with an estimate of your maximum heart rate — most simply 220 − age — and divides the range into five zones, each a band of percentages that trains a different mix of endurance and intensity. For a more personal result, the Karvonen method folds in your resting heart rate, which reflects fitness. The numbers are estimates with real individual spread, so use them as guidance and cross-check against how the effort feels.
Reviewed: June 20, 2026 · Author: Naveen P N, Founder — AI Calculator · Verified against: the 220−age estimate and Karvonen reserve method. Not medical advice.
The heart rate equations
The percentage-of-max method is simplest: multiply your estimated maximum by each zone's boundaries. The Karvonen method instead works from heart rate reserve — the gap between maximum and resting — and adds the resting rate back, which shifts the zones to suit your fitness. A fitter person with a lower resting heart rate gets a wider reserve and slightly different targets. Both rest on an estimated maximum, so the zone edges are approximate either way.
Worked example — a 30-year-old
Scenario: age 30, using the percentage-of-max method.
With a maximum of 190 bpm, easy aerobic work (Zone 2) sits at 114–133 bpm, steady aerobic running (Zone 3) at 133–152, and harder threshold work (Zone 4) at 152–171, with all-out efforts (Zone 5) above 171. If this runner has a resting heart rate of 60, the Karvonen method shifts the zones slightly upward because it works from the 130-beat reserve. Either way, the boundaries are guides — the 220−age estimate can be off by 10+ bpm, so let perceived effort sanity-check the watch.
Frequently Asked Questions
220 − age (or Tanaka 208 − 0.7×age). Age 30 → 190 bpm. A population average, ±10+ bpm.
Z1 50–60%, Z2 60–70%, Z3 70–80%, Z4 80–90%, Z5 90–100% of max HR.
~Zone 2 (60–70%). A higher fat fraction, but higher intensity burns more total calories.
(max − rest) × % + rest. Uses heart-rate reserve, so it accounts for fitness. Add resting HR to use it.
Estimates (±10–12 bpm). A lab/field test gives a measured max. Consult a doctor if you have heart issues.