Describe how heat and cold applications affect tissue healing. Why is it important to alternate periods of temperature applications to the affected tissue area?
Heat produces vasodilation and brings increased blood flow to the area thereby reducing pain and promoting healing. Blood viscosity is decreased along with muscle tension but there is an increase in tissue metabolism and capillary permeability. However, prolonged exposure of heat to injured tissue can lead to destruction of epithelial cells and cause further tissue injury. Cold produces vasoconstriction and the reduction of blood flow to the area. Blood viscosity is increased but tissue metabolism and muscle tension is decreased. Initially the application of cold can produce relief due to a protective anesthetic response, yet with prolonged exposure this can lead to tissue ischemia.
