Basal Metabolism is the minimum amount of energy needed by the body for maintenance of life when the person is at complete physical and mental rest and having normal body temperature and in the post -absorptive state (12 hours after the intake of last meal). Basal Metabolic Rate (BMR) is a measure of the energy required by the activities of resting tissue.
The Basal Metabolic rate can be measured directly from the heat produced (using a Respiration Calorimeter and Metabolic Chamber) or indirectly from O2 intake and CO2 expenditure when the subject is at rest.
The rate of energy use for metabolism under basal metabolism is usually expressed as kcal/kg body weight per hour. The factors affecting BMR is presented in table 9.5