A common form of sweating is called primary hyperhidrosis. In medical literature it often referred to as a disease designated as idiopathic hyperhidrosis or essential hyperhidrosis. In this form, the reasons for sweating are unexplained and has no recognizable causes.
It often begins at puberty and can continue to develop pathalogically. Manifestation in the hands, feet and armpits are most common, but the head, neck and trunk can also become problematic with primary hyperhidrosis. The areas of the body in which they occur may be isolated or in combination.
Primary hyperhidrosis is often invoked by emotions and is known to be called emotional sweating. When sleeping, the sweating typically lessens, giving even more support to this theory. Fear, stress and anxiety can also stimulate sweat glands.
In the mid-brains, the areas that control sweating communicate with the area that is responsible for emotions in the brain. With this close connection, not only does one sweat when in situations of physical exertion or intense heat, but also when in situations of psychological pressure, scared or stressed.