Is the Karvonen formula more accurate than %Max HR?

HRR correlates more closely with oxygen uptake reserve than the %Max HR method does, making it the better proxy for training intensity, though neither measures a lactate or ventilatory threshold directly.

Should I trust my watch's default heart rate zones?

Most watches default to the %Max HR method for convenience, not accuracy. If the maximum behind it was estimated from age rather than measured, it likely carries the seven-to-twelve-beat-per-minute error commonly cited for 220 minus age, following Robergs and Landwehr’s 2002 review.

Do heart rate zones change as fitness improves?

Under Karvonen, often, since a falling resting heart rate lowers the target and the calculation is worth revisiting periodically. Under the %Max HR method, zones move only when the maximum is re-measured, and few watches do that separately for each sport.

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Karvonen versus %Max HR: which HR zone method should you use?

31 July 2026

the5krunner

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%Max HR and Karvonen can put the same runner's Zone 2 several beats apart. The maths,…