1 - Enter your age, resting heart-rate, and gender.
2 - Enter your maximum heart-rate if you know it - otherwise leave that field blank and it will be estimated as follows:
(Males: 214-(0.8*age). Females: 209-(0.7*age).
3 - Press "Calculate".
The training zone values are calculated using the Karvonen formula:
Heart rate = ((Max HR-Resting HR)*%X/100)+Resting HR. (where %X =%MAX, e.g. 60)
4 - Press "Reset" after each calculation to prevent inaccurate results.