Heart Rate Zones: How to Calculate Yours (Tanaka and Karvonen)
Training by heart rate helps you go easy on easy days and hard on hard days — the part most people get wrong. It starts with two numbers: your maximum heart rate and your resting heart rate.
Maximum heart rate
"220 − age" is popular but imprecise. The Tanaka formula, 208 − 0.7 × age, was built from far more data and is usually closer. At 40 both give 180; at 55, Tanaka gives about 170 vs 165. Any formula can be off by 10–20 beats for an individual; a supervised exercise test is the only accurate way.
Personalizing with resting heart rate (Karvonen)
Measure your pulse for 60 seconds in the morning before getting up, on a few days, and average it. Then:
target = resting + (max − resting) × intensity
Example: age 40, max 180, resting 60 → reserve 120. Zone 2 at 60–70% = 60 + 72 to 60 + 84 = 132–144 bpm.
The five zones
| Zone | Intensity | Feels like |
|---|---|---|
| 1 | 50–60% | Very easy; warm-up and recovery |
| 2 | 60–70% | Easy; you can hold a conversation |
| 3 | 70–80% | Moderate; short sentences only |
| 4 | 80–90% | Hard; a few words at a time |
| 5 | 90–100% | Maximum; very short efforts |
For endurance, most training time belongs in zone 2, with a smaller share of hard intervals in zones 4–5. The heart rate zone calculator builds the table for you.
Important exceptions
Beta-blockers and some other medicines lower heart rate, making these zones wrong. If you take them, have a heart condition, or feel chest pain, dizziness or unusual breathlessness, talk to a doctor before training hard.
Fuel the training: estimate daily needs with the calorie calculator.