All heating modalities produce the desirable therapeutic responses of analgesia, increased metabolism, and decreased viscosity of collagen primarily by temperature elevation. The temperature distribution produced in the tissues and the site of peak temperatures should bel understood for selection and application of the modality.

The purpose of this study was to evaluate the changes of temperature and pain (VAS) produced by the superficial heating modalities with 100 W and 150 W infrared, hydrocollator pack, whirlpool, and paraffin.

The modalities were applied to 86 patients with low back pain and joint deformities or contractures of extremities. A statistically significant differences in temperature elevation and pain reduction were found setween the different heat modalities during application. Hydrocollator pack and paraffin applied on the low back showed the highest degree of elevation of skin temperature in 10 minutes. Infrared of 100 W white bulb on the hand produced the least degree of temperature elevation after 30 minutes application. With hydrocollator pack application low back pain was reduced most outstandingly, in 10 minutes but with the infrared application on the hand little pain was produced in 5 minutes instead.