Your Basal Metabolic Rate (BMR) is the energy expended by the body at rest. This continual work makes up about 60-70% of the calories we use and includes the beating of our heart, breathing, and the maintenance of body temperature. Your BMR is influenced by a number of factors, including age, weight, height, gender, environmental temperature, dieting and exercise habits.

The BMR is most accurately measured at rest (but not asleep) in a special environment, but it can be estimated.