THE CLINICAL APPLICATION OF HEAT 



D. S. EVANS, Ph.D. & K. MENDELSSOHN, D.Phil. 

 Clarendon Laboratory^ Oxford 



Introduction 



IN VIEW of the fundamentally important part which heat 

 energy plays in the life of the human being, and the prom- 

 inence of the physiological processes regulating the body 

 temperature, it is remarkable that so very little is known about 

 the quantitative administration of heat in clinical practice. In 

 most cases, the recommendation of heat treatment goes no further 

 than the ancient prescription "Keep the patient warm." Coupled 

 with our ignorance of quantitative administration, there is also 

 a remarkable lack of information about the exact therapeutic 

 effects produced by heat. While it is generally true that by 

 the application of heat energy the production of heat by the 

 body can be supplemented to the advantage of the patient, we 

 have to face the fact that, for instance, the application of a hot- 

 water bottle produces an increase in body heat greater than the 

 amount actually transmitted from the bottle. Clinicians are also 

 aware of therapeutic effects produced by radiant heat at depths 

 in the tissues quite out of the reach of the radiation employed. 



Physical Basis of Heat Therapy 



However, before all these questions can be discussed, we must 

 first establish a basis for the dosage of heat treatment and, since 

 the methods of administration of heat are governed by the laws 

 of physics, our first concern must be to establish a sound physical 

 basis for clinical heat treatment. Normally the body disposes of 

 about 100 kilogram calories of heat per hour, and it is therefore 



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