Target Heart Rate Calculator

Variables considered

The target heart rate calculator consists of two variables, the age of the subject and the resting heart rate (RHR).

Please note that the normal range for RHR is considered to be in adults between 60 and 100 bpm.

Lower values are indicative of a better cardiovascular fitness (athletes usually have lower RHR, even closer to 40 bpm).

The RHR should be measured first thing in the morning, after getting up from bed.

The Karvonen method explained

The famous equation is the following:

Target Heart Rate = ((max HR − Resting HR) × %Intensity) + Resting HR

However, in order to get to it, there are some steps to follow:

■ Step 1 requires the calculation of the maximum heart rate (MHR), which is dependent on the age of the subject (in years): MHR = 220 - Age;

■ Step 2 uses the above MHR to determine the heart rate reserve (HRR): Max heart rate – Resting heart rate;

■ Steps 3 and 4 determine the minimum and maximum of the target heart rate interval by multiplying MHR with 0.6, respectively 0.8. In order to maximize cardiovascular exercise, it is recommended to work in the zone of target heart rate which is considered to be at 60-80% of maximum heart rate;

■ Step 5 averages the minTHR and maxTHR to extract an “ideal”, average THR.

It is important to note that the above calculations are only as exact as the formula is aimed to be and that the 0.6 and 0.8 values are subjective.

About the original study

Heart rate can be recorded during training sessions, thus obtaining an average rate which is then compared with the max and rest heart rates. Calculating these, can help with the monitoring of training intensities.

The laboratory method of calculating THR is by measuring endurance performance. The subject carries out a treadmill training in which the speed is increased in stages. Oxygen uptake, the lactic acid concentration in the blood and corresponding variations in the heart rate are measured concomitantly.

Marrti Karvonen was an expert in exercise science, created the famous training heart rate equation, the Seven Countries Study and the North Karelia project in Finland. He was also consultant to the World Health Organization.

Target heart rate table including the zones

Table source: American Heart Association

Original source

Karvonen J, Vuorimaa T. Heart rate and exercise intensity during sports activities. Practical application. Sports Med. 1988; 5(5):303-11.

Other references

1. Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. J Am Coll Cardiol. 2001; 37(1):153-6.

2. Hofmann P, Von Duvillard SP, Seibert FJ, Pokan R, Wonisch M, Lemura LM, Schwaberger G. %HRmax target heart rate is dependent on heart rate performance curve deflection. Med Sci Sports Exerc. 2001; 33(10):1726-31.

3. Sandvik L, Erikssen J, Ellestad M, Erikssen G, Thaulow E, Mundal R, Rodahl K. Heart rate increase and maximal heart rate during exercise as predictors of cardiovascular mortality: a 16-year follow-up study of 1960 healthy men. Coron Artery Dis. 1995; 6(8):667-79.