basal metabolic rate is the number of calories required to keep your body functioning at rest. bmr is also known as your body's metabolism; therefore, any increase to your metabolic weight, such as exercise, will increase your bmr.
the basal metabolic rate decreases almost linearly with age. it is shown that the decrease in muscle mass relative to total body may be wholly responsible for the age-related decreases in basal metabolic rate. energy consumption by physical activity also decreases with atrophic changes of skeletal muscle.
