Basal metabolism refers to the energy requirements of the human body in a fasting, awake and quiet state with an ambient temperature of 18 to 25°C to maintain basic physiological activities of the body. Basal metabolism is usually expressed in terms of basal metabolic rate, which is measured as the rate of energy metabolism of the human body in a quiet and awake state, unaffected by factors such as ambient temperature, food, muscular activity, and mental stress. The generalized formula for basal metabolic rate = (pulse rate + pulse pressure) – 111 can be used to roughly calculate the body’s basal metabolic rate. The basal metabolic rate of normal human beings is relatively constant, and is usually slightly higher in males than in females, higher in adolescents and children than in adults, and gradually decreases in adulthood. In clinical practice, the basal metabolic rate is also used to diagnose thyroid disorders. It is advisable to seek medical attention for abnormalities of basal metabolic rate.