BMR: Is the daily minimum level of energy or calories the body requires when at rest (including sleeping) to function effectively.
An increase in muscle mass will speed up basal metabolic rate (BMR). A person with a high BMR burns more calories at rest than a person with a low BMR.
Resting Metabolism
60-70% of daily energy use is for basal metabolism, 20-30% is for daily activity and 10% for diet-induced thermogenisis.
Know your RM to avoid over-eating and to increase muscle mass.