*By regulating blood flow to the skin, sympathetic nerves can increase or decrease heat loss. By dilating surface vessels, sympathetic nerves increase blood flow to the skin and therby accelerate heat loss. Conversely, constricting cutaneous vessels conserves heat.
*Sympathetic nerves to sweat glands promote secretion of sweat, thereby helping the body cool.
*By inducing piloerection (erection of hair), sympathetic nerves can promote heat conservation.