This type of heat therapy was developed back in 1947 and has been used by numerous therapists ever since. Heat therapy is the application of local or general heat with a therapeutic effect. A very important factor is the conduction coefficient, which expresses how long the heat is retained and how quickly it is released to the body. The speed of a biochemical reaction is crucial for initiating a healing process. Heat improves blood circulation and thus the metabolism, which is the basis for this biochemical reaction.