Sweat is secreted by the eccrine glands, present all over the body, that play an important role in thermoregulation. People devoid of sweat glands have a hard time in maintaining a stable body temperature. However, some areas, like the palms and soles do not really contribute to this thermoregulation. Sweating in these areas is
triggered more by emotions then heat. Moreover, in individuals who are somewhat emotional, "flushing" adds up, making an already embarrassing situation even worse.
There are about 3 millions sweat glands, of the eccrine type, covering our skin surface from head to toe. Their density varies from one part to another. The back contains
64 glands /cm2, the forearm 108 glands/ cm2, and the forehead 181 glands/ cm2. The palms and soles contain each from 600 to 700 glands / cm2.
The thermostat that regulates the body temperature is located in the hypothalamus. When the body temperature rises beyond a certain level, sweating is activated through the sympathetic nervous system and the nerve terminals responsible for the sweat secretion. In the case of primary HH, nerve impulses triggered by emotions may reach the hypothalamus that activates the sweat process.