WATSU is an acronym, based on the terms Water and Shiatsu. It is a relaxing form of hydrotherapy which is performed in 35° C (95° F). Practitioners claim WATSU to lower muscular tonus as well as stress and to relief pain. Clinically relevant regulation of muscular tonus in spastic hemiparetic patients due to WATSU was observed by Chon; significant reduction of pain in patients suffering fibromyalgia by Faull.