Fitness guide
Heart Rate Zones Guide
Use zones to describe intensity ranges, not as rigid pass-or-fail boundaries.
Updated 16 October 2026 • Reviewed by Tools by Layna Editorial Team • General information only
Name the zone method first
A heart-rate zone describes a range under a chosen method. A percentage of maximum heart rate and a percentage of heart-rate reserve are different calculations. Do not copy the same percentage between them and expect the same beats per minute.
An age-predicted maximum such as 220 − age is a population estimate. It does not establish an individual’s true maximum. The American Heart Association uses broad percentage-of-maximum ranges as a general guide and notes that medication and heart conditions can change the appropriate target.
Worked example: why two 60% targets differ
Take an illustrative 40-year-old with a resting rate of 60 bpm. The age-predicted maximum is 220 −40 = 180 bpm. Sixty percent of that maximum is 108 bpm.
Heart-rate reserve is 180 −60 =120 bpm. Sixty percent of reserve added back to rest is 60 +0.60 ×120 = 132 bpm. Both calculations use 60%, but the answers differ by 24 bpm because the denominator differs.
How to use zones in a gym session
Read the method and labels used by the calculator or device before setting a treadmill or bike target. Keep the device and calculation method consistent when comparing similar sessions. A machine display and a wrist watch can disagree, especially while gripping handles or changing intensity quickly.
Use the talk test or perceived effort alongside heart rate. Check whether the displayed reading fits the effort you actually feel. Resistance-training sets and short intervals are different from steady cardio; a lagging or erratic reading should not make you chase a higher effort merely to reach a coloured band.
When the number needs more context
Heat, fatigue, caffeine, stress, illness and hydration can alter a reading or how a session feels. Record the setting and the activity, not just peak bpm. Compare repeated similar sessions rather than treating one number as a verdict on fitness.
If you take medication affecting heart rate or have a heart condition, ask your health professional about appropriate intensity. Stop and seek appropriate care for chest pain, fainting or unusual breathlessness. General zones do not provide medical clearance or a rehabilitation prescription.
Frequently asked questions
Why do two zone calculators give different numbers?
They may use different predicted maximum-heart-rate equations, different band boundaries or different denominators. Compare the method before comparing the result.
Is 220 minus age my measured maximum heart rate?
No. It is an age-based estimate. Do not interpret its apparent precision as a measured individual limit.
Can I compare a 60% reserve zone with 60% of maximum?
No. Reserve subtracts resting heart rate first, then adds it back after applying the percentage. The worked example shows why the resulting bpm differs.
Sources and method
- American Heart Association target heart rates — Age-predicted maximum, broad intensity guidance and medication limitations.