Heart Rate Zone Calculator

Calculator

How we calculate it

Training zones are expressed as intensities relative to maximum heart rate, which almost nobody has actually measured. This tool estimates it with the Tanaka equation, 208 minus 0.7 times age, derived from a meta-analysis of 351 studies and cross-validated in 514 healthy subjects. It tracks measured maximum heart rate across the adult age range better than the familiar 220-minus-age rule, which overestimates in younger adults and underestimates in older ones — the two happen to agree exactly at age 40. Zones follow the conventional five-zone model at 50–60%, 60–70%, 70–80%, 80–90% and 90–100% of that maximum. If you supply a resting heart rate, the tool switches to the Karvonen heart-rate-reserve method instead: target equals resting plus the chosen percentage of the gap between resting and maximum. Reserve-based zones are more individualized and generally sit higher than straight percentage zones. Each zone is labeled with how the effort should feel, because perceived exertion corrects for the heat, dehydration, caffeine, stress and fatigue that shift heart rate at a given effort.

Important limitations

• Age-based equations predict a population average. Individual maximum heart rates vary by roughly 10 to 20 beats per minute in either direction at any age, so the zones may not match your physiology.
• Only a supervised maximal exercise test can establish your actual maximum heart rate.
• Beta blockers, other rate-limiting medications, pacemakers and conditions such as atrial fibrillation change heart rate response, and these equations do not apply in those situations.
• Heart rate at a given effort drifts upward over a long session and rises with heat, dehydration, caffeine, stress, illness and altitude. A zone boundary is not a fixed line.
• Wrist-based optical monitors lose accuracy during high-intensity and interval work. A chest strap is considerably more reliable for zone training.
• These zones are general fitness education, not an individualized exercise prescription. If you have a heart condition, are recovering from a cardiac event, or have been advised to limit exertion, your plan should come from your clinician or a cardiac rehabilitation team.