Target Heart Rate Zones
Calculate heart rate training zones using the Karvonen formula from your age and resting heart rate. Shows 5 zones from light aerobic to maximum effort for exercise planning.
HRmax
185 bpm
- Z1 — Recovery (50–60%)125–137 bpm
- Z2 — Aerobic base (60–70%)137–149 bpm
- Z3 — Tempo (70–80%)149–161 bpm
- Z4 — Threshold (80–90%)161–173 bpm
- Z5 — VO₂ max (90–100%)173–185 bpm
Educational tool. Not a substitute for clinical judgment, professional diagnosis, or treatment. Always verify with current guidelines.
How to use the target heart rate zones
Enter age and resting heart rate. The Karvonen formula returns the five training zones based on heart-rate reserve.
Formula & explanation
HRmax = 220 − age. HRR = HRmax − HRrest. Zone HR = HRrest + (intensity × HRR).
Examples
Age 35, RHR 65: Z2 (aerobic base) ≈ 122–134 bpm. Z4 (threshold) ≈ 145–158 bpm.
Frequently asked questions
- Is 220 − age accurate?
- It's a population estimate; individual HRmax varies by ±10 bpm. A maximal exercise test gives the truest number.
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