Heart-rate zones turn exercise intensity into a range you can watch on a wearable or check by taking your pulse. They are estimates, not speed limits. The American Heart Association describes moderate activity as roughly 50–70% of estimated maximum heart rate and vigorous activity as roughly 70–85%. Its simple estimate for maximum heart rate is 220 minus age.
Age-based chart
| Age | Estimated maximum | Moderate 50–70% | Vigorous 70–85% |
|---|---|---|---|
| 20 | 200 bpm | 100–140 bpm | 140–170 bpm |
| 30 | 190 bpm | 95–133 bpm | 133–162 bpm |
| 40 | 180 bpm | 90–126 bpm | 126–153 bpm |
| 50 | 170 bpm | 85–119 bpm | 119–145 bpm |
| 60 | 160 bpm | 80–112 bpm | 112–136 bpm |
| 70 | 150 bpm | 75–105 bpm | 105–128 bpm |
Example: at age 40, 220 − 40 gives an estimated maximum of 180 bpm. Fifty percent is 90, 70% is 126, and 85% is 153. The Heart Rate Zones Calculator performs the same calculation for any adult age and also offers a resting-heart-rate method.
The Karvonen method
The Karvonen formula uses heart-rate reserve: estimated maximum minus resting heart rate. Target = resting rate + intensity × heart-rate reserve. For a 40-year-old with a resting rate of 60, the reserve is 120. A 60% target is 60 + (0.60 × 120) = 132 bpm. This can be more individualized than a percentage of maximum alone, but it still inherits the uncertainty of the age-based maximum estimate. Measure resting heart rate when calm, ideally before getting out of bed, and use a consistent method.
Why your real numbers may differ
“220 minus age” describes a population average. Fitness level, heat, hydration, stress, illness, elevation, sleep, and sensor error can all move a reading. Beta blockers and other medications can change the heart-rate response to exercise. Perceived effort and the talk test are useful companions: moderate work usually allows conversation, while vigorous work makes full sentences difficult.
If you have cardiovascular disease, take medication that affects heart rate, are returning after a long break, or develop chest pain, faintness, or unusual shortness of breath, get individualized guidance from a qualified health professional. A generic calculator cannot diagnose a condition or set a safe clinical limit.
Sources and further reading
Informational only; not medical advice. Reviewed September 2026.