Physiology and relevance of human adaptive thermogenesis response

• Brown fat activity defends core temperature while minimizing energy expenditure.
• Human brown adipose tissue mass and activity can be expanded.
• Human brown adipose tissue activation has beneficial metabolic consequences.
• Human brown fat activation alone is insufficient to promote significant weight loss.

In homoeothermic organisms, the preservation of core temperature represents a primal function, and its costs in terms of energy expenditure can be considerable. In modern humans, the endogenous thermoregulation mechanisms have been replaced by clothing and environmental control, and the maintenance of thermoneutrality has been successfully achieved by manipulation of the micro- and macroenvironment. The rediscovery of the presence and activity of brown adipose tissue in adult humans has renewed the interest on adaptive thermogenesis (AT) as a means to facilitate weight loss and improve carbohydrate metabolism. The aim of this review is to describe the recent advancements in the study of this function, and to assess the potential and limitations of exploiting AT for environmental/behavioral, and pharmacological interventions.