What effects do hypothyroidism and hyperthyroidism have on metabolism?

Concepts to Consider: Hypothyroidism--when there is almost no secretion of thyroid hormones in an adult, the person has a 40% reduction in basal metabolic rate. This slows down physical and mental activities. The person may feel sleepy, low in energy, and confused. Hyperthyroidism--when there is an over secretion of thyroid hormones, metabolic rate can increase by more than 60%. The person often feels hungry due to a rapid use of nutrients, nervous, emotionally unstable, and irritable.