Heavy perspiration; also called hyperhidrosis. Polyhidrosis is a condition in which intense sweating on the palms, soles of the feet, and underarms occurs whenever the person is under stress. As many as 1 percent of people experience polyhidrosis, which is not a harmful condition but one that can be embarrassing. In some cases, polyhidrosis is the result of a genetic disorder called emotional hyperhidrosis.