How this calculator works
Karvonen intensity is a fraction of the difference between maximum and resting heart rate. It is not the same as a percentage of maximum heart rate. If no maximum is available, the separate Tanaka adult population estimate can be selected. Medication, illness and individual variation can make either prediction unsuitable for exercise planning. The result is an estimate for information only and is not medical advice.
Formula
Target = rest + intensity x (maximum - rest). Intensity = (target - rest)/(maximum - rest). Optional Tanaka maximum = 208 - 0.7 x age.
Worked example
With resting rate 60, maximum 180 and intensity 60%, reserve is 120 and target is 132 beats/min. A target of 150 with the same rates is 75% of reserve.
Advertisement
Frequently asked questions
Is 60% reserve the same as 60% maximum?
No. With a 180 maximum and 60 resting rate, 60% maximum is 108, while 60% reserve gives 132 beats/min.
How reliable is an age-predicted maximum?
It describes a population average, with substantial individual variation. It is not a substitute for an appropriately supervised assessment.
Can I use this while taking heart-rate medication?
A clinician should set exercise guidance when medication changes the heart-rate response. This arithmetic cannot account for that effect.