Effect of foot bathing on distal-proximal skin temperature gradient in elders

Increased distal (foot)-proximal (abdominal) skin temperature gradient (DPG) has been associated with better sleep initiation. Warm foot bath can affect distal skin temperature to change DPG. However, the optimum water temperature and duration necessary to raise DPG has not been established. This study explored the effects of 1-h foot bathing at two water temperatures of 40 and 41 degrees C, respectively, on DPG in Taiwanese elders (n=6, ages 60-73 years). Each subject's feet and legs were immersed in a temperature-controlled water tub to 20 cm above the ankles for 60 min in each of two water temperatures. Oral, abdominal, and foot temperatures were taken during (at 10-min intervals), and after (at 1-min intervals) foot bathing. DPG was calculated by subtracting abdominal temperature from foot temperature. Results showed the value of DPG was significantly increased in the 10th min bathing at both water temperatures and maintained above 0 degrees C. DPG gradually declined after bathing at both water temperatures. The value of DPG with 41 degrees C water was slightly higher than 40 degrees C. All subjects tolerated both bathing temperatures well for 1h. Both 40 and 41 degrees C foot bathing for 1h can increase the DPG and may be an effective way to affect whole body skin blood flow and trigger heat dissipation.