The thermogenic effect of thyroid hormone and its clinical implications.

Clinicians are very familiar with cold or heat intolerance in patients with altered thyroid function. While nonspecific, these symptoms have some predictive value in the diagnosis of thyroid dysfunction. Involuntary changes in weight are also perceived as indicators of abnormal thyroid function, often prompting laboratory testing of thyroid gland function. Most of the clinical manifestations of thyroid dysfunction in adults are directly or indirectly derived from the stimulating effect of thyroid hormone on thermogenesis and energy turnover. Even so, the relationship between these effects and energy balance and body weight is not simple. This review examines the thermogenic effect of thyroid hormone and how it affects some of the manifestations of hypoand hyperthyroidism, energy balance, and body weight.