Moist Heat: acts as an analgesic, antispasmodic, decongestive and sedative.  It is used to help raise the temperature of soft tissue directly below the surface of the skin.  It enlarges blood vessels, and relaxes muscle spasms.  It is usually used to relieve long term spasms and muscle tightness.  It can increase flexibility,  range of motion, and promote increased circulation to speed the healing process.  It relaxes muscle tension and reduces stiffness in joints.