The AM3 activity and sleep tracker calculates calories burned throughout the day according to physical activity exerted and also according to the user's Basic Metabolic Rate (BMR). The BMR is the amount of calories burned naturally by the body at rest (for the work of the heart, lungs, brain, etc.).
The Basic Metabolic Rate is determined by age, sex, height and weight.
Our tracker displays the total calories burned (by exercise as well as the BMR) from midnight each day.
That's why, when you wake up, even if you haven't taken a step you will see a certain amount of calories burned.
*credit to Sylvain of iHealth Labs EU