Objective To study the heating effect on skin of the therapeutic sand used in the Uyghur medicine. Methods We have continuously collected data of the dynamically changing surface body temperature during the course of sand therapy. Having applied the surface skin response equations, we calculated the situational effects on surface skin tissue by examining different temperature fields and time segments. All the data was collected by a 2 700 type multichannel data collection apparatus. Results It was found that, in the period of mid June to mid August every year, the air temperature of the sand therapy facility was 40?2.3℃ at the time 15∶00 to 18∶00 in the afternoon and the sand used as a medicinal poultice could be maintained at the temperature of 38?4.6℃ at the depth of 20 cm from the surface of the sand. During the process of sand therapy, the skin surface temperature rises rapidly, up to 39℃,but the skin surface temperature falls subsequently, as the heat stimulates perspiration and the cooling effect of evaporation takes place to 36?0.32℃. Two to three hours later, the surface skin temperature gets stable and maintained at 36?0.6℃. Conclusion When the sand temperature reached 43℃, it could not hurt the skin and tissue, because the body temperature could balance with sand temperature at an ideal temperature for the skin. The ideal time for sand therapy is during the period from June and August, at 15∶00~18∶00 every day. When the air temperature reaches 40?2.3℃, the sand temperature will be below 38?4.6℃. Under these conditions the human body should be buried under the sand at the depth of 20 cm for a period of one half to one hour to achieve therapeutic effects.

Objective To investigate the mechanism of heat transfer process in sand therapy in Uyghur medicine. Methods A mathematical model was developed to describe the heat transfer process between human body and the sand during sand therapy. Temperature field was numerically simulated and analyzed based on this model. Results Temperature field in both human tissues and sand was calculated. The surface temperature of the sand and skin surface changed significantly at the beginning of the sand therapy, while sand temperature (5 cm deep) almost kept constant. The skin temperature dramatically increased at the beginning of the sand therapy and then slightly dropped. When sand was deeper than 10 cm, the thickness of sand would not influence the temperature field in human tissues during sand therapy. High initial temperature of sand might cause harmful skin burn. Threshold skin burn occurred if initial temperature of sand was higher than 64.6 ℃ and if the therapy lasted more than 30 minutes.Conclusion Temperature fieled in human tissues varies significantly with the initial temperature of sand, thickness of sand, and duration of therapy.