TRAINING TERMS

Heart-rate zones

A way to read exercise intensity, using your own resting heart rate and an estimated maximum.

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What a zone tells you

Heart rate is the number of beats per minute. During exercise it offers one view of how hard you are working. A zone groups a range of heart rates so a plan can describe an intensity without prescribing the same pace to everyone.

Zone numbers are labels within a particular system. Another app or coach may use different boundaries, so compare the calculation before comparing the numbers.

How Training Compass draws the bands

The App estimates maximum heart rate as 208 − 0.7 × age in completed years. Heart-rate reserve is that estimate minus your resting heart rate. Each boundary is resting heart rate + a percentage of that reserve.

Zone 1 is below 60% of reserve; Zone 2 is 60% to below 70%; Zone 3 is 70% to below 80%; Zone 4 is 80% to below 90%; Zone 5 is 90% and above. A reading exactly on a boundary belongs to the higher zone.[1][2][3][4][5]

For an arithmetic example, a resting heart rate of 60 and an estimated maximum of 180 give a reserve of 120. The four boundaries are 132, 144, 156 and 168 beats per minute. These example numbers are not your targets.

Use the number alongside how you feel

These percentages are of heart-rate reserve, not maximum heart rate. The bands do not measure your lactate or breathing thresholds. An age-based maximum is an estimate, so a zone label cannot prove that an effort is right for you.

The CDC describes a simple talk test: moderate effort generally allows conversation but not singing; vigorous effort leaves only a few words between breaths. This is another intensity clue, not an exact translation into the App’s five zones.

Temperature, emotions and medication can affect heart rate. If you have a heart condition or take medication that affects your pulse, ask your clinician which intensity guidance to use. Public zone descriptions cannot set your personal limits.

Sources & further reading

Reviewed September 14, 2026