|Posted on April 28, 2016 at 11:10 AM|
The normal body temperature is 98.6*F. Physiologically, the body strives to maintain this temperature.When heat or cold is applied to the body, certain physiological changes occur. The nature and extent of those changes depend on the temperature and duration of the application and the size of the body area and thermal conductivity of the body part involved. The physiological effects from the application of heat and cold are predictable,which makes the use of heat and cold a powerful therapeutic agent.
The application of heat causes a vasodilation and an increase of circulation in an attempt to dissipate the heat. A general application of heat (hot salt bath of sauna for example) will raise the body temperature, causing feverlike reaction.There is profuse perspiration,the pulse increases,and the white blood cell count increases. A local application will cause local reddening (due to vasodilation), increased metabolism and white blood cells migration to the area,relaxation of local musculature,and a slight analgesia(the inability to feel pain).
The quick, short application of cold is stimulating,whereas prolonged application of cold depresses metabolic activity.General application of cold reduces body temperature (hypothermia) and should be done under strict supervision.Local applications of cold (ice) cause a reduction of nerve sensitivity, circulation, muscle spasms, and spasticity. They have a numbing, anesthetic effects that makes the valuable in the relief of acute pain from bursitis, soft tissue injury, burns, and neuralgia.
Contrast heat and cold applications is one of the most effective methods of increasing local circulation. Contrasting hot and cold cause an alternating vasodilation and vasoconstriction of the blood vessels in an area. Increased local circulation relieves stiffness and pain do to trauma and stimulates healing of injury and wounds.