💓 Target Heart Rate Zones

Written and maintained by the PhDino author · Last reviewed 21 September 2026 · A documented rule of thumb, pinned by automated tests · how PhDino checks its numbers

Estimating a maximum heart rate from age, and a moderate-to-vigorous exercise target zone from that estimate.

Exercise intensity is commonly guided by heart rate as a percentage of an estimated maximum, since heart rate rises fairly predictably with exercise intensity for most people and is easy to measure in real time. Because directly testing someone's true maximum heart rate requires supervised maximal exertion, a simple age-based formula is commonly used as a practical estimate instead.

A target zone of roughly 50–85% of estimated max heart rate is a widely cited general range for moderate-to-vigorous aerobic exercise, spanning from a comfortably sustainable pace at the low end toward a genuinely challenging effort near the top.

Key formula

Estimated max heart rate = 220 − age
Target zone = 50–85% of estimated max heart rate

Notes & limitations

• "220 minus age" is a simple, widely used rule of thumb, not a precisely validated formula — actual maximum heart rate varies considerably between individuals of the same age, and more refined formulas exist (though none are dramatically more accurate for a general population).
• Heart rate response to exercise is also affected by fitness level, certain medications (particularly heart-rate-affecting drugs like beta blockers), and health conditions — any of which can make an age-based estimate a poor match for a specific individual's actual physiology.