The OwnCal feature calculates the number of calories expended during an exercise session based on the user's weight, heart rate and gender. Counting of the calories burned begins immediately when the user's heart rate has reached the OwnZone , which is also the most effective and safe heart rate zone for calorie consumption.

You can easily follow the effect of exercising displayed in real-time. The higher the heart rate, the faster the energy expenditure accumulation. Energy expenditure depends also on body weight; the heavier the weight the higher the energy expenditure. At the end of the exercise session the Polar M series heart rate monitors shows not only the energy expenditure of that particular session but also the cumulative total energy expenditure value. Now you know how many kilocalories you consumed by exercising during a week.  In addition the M series also keeps track of how many calories have been burned from fat.

In health-related exercise sessions the recommendation for the target energy expenditure for a day is 150 kcal and for weekly accumulation 1000 kcal (Physical Activity and Health: A report of the Surgeon General, 1996). For a fitness exerciser the corresponding recommendations are 300 and 1500-2000 kilocalories.