Target Heart Rate Calculator

Target Heart Rate (THR) range values are often calculated to ensure exercise intensity is maintained at a desired level. This calculator automatically calculates THR ranges.

The Karvonen formula is often used for this purpose and calculates results as a function of heart rate reserve (HRR) and maximum heart rate (HRmax).

• HRR = HRmax - HR rest
  Where HRrest is the resting HR of the individual

HRmax may be calculated by a maximal exercise test (value to be entered into the calculator directly) or by using an age predicted formula.

There are two formulae currently favoured:

1. HRmax = 220 – age (which is reported to be simpler to use)
2. HRmax = 206.9 – (0.67 x age) (reported to be more accurate [#gellish-rl-goslin-br-olson-re-et-al.-2007]

Target HR range is calculated as follows:

• THRR= (HRR x desired training intensity) + HRest

Target HRmax (THRmax) is caluclated as follows:

• THRmax= (desired training intensity) x (HRmax)

For example, if calculating THRR for a 45 year old with a resting HR of 72bpm, whereby training intensity is 40-59%:

1. HRR = [(220 – 45) – 72] = 103bpm
2. THHR = 103 * 0.4 + 72 = 113.2 bpm and 103 * 0.59 + 72 = 132.77 bpm
3. THHR = 113 – 133bpm

Medications such as beta blockers directly impact upon an individual’s heart rate. For this reason, alternative measures of exercise intensity may be more appropriate. Please refer to the exercise sections of this website before prescribing target heart rates to patients.