Basal Metabolic Rate (BMR) is the minimal rate of energy expenditure per unit time by endothermic animals at rest. It is reported in energy units per unit time in watt (joule/second) Metabolism comprises the processes that the body needs to function. Basal metabolic rate is the amount of energy expressed in calories that a person needs to keep the body functioning at rest. Some of those processes are breathing. blood circulation, controlling body temperature, cell growth, brain and nerve function, and contraction of muscles. The metabolic rate can be affected by some drugs, such as antithyroid agents, drugs used to treat hyperthyroidism, such as propylthiouracil and methimazole, bring the metabolic rate, down to normal and restore euthyroidism. Majorly the Thyroid hormone regulated the basal metabolic rate and an increase in the secretion of this hormone is referred to as hyperthyroidism and an decreased secretion is called hypothyroidism.