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 footbath 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 °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 °C. DPG gradually declined after bathing at both water temperatures. The value of DPG with 41 °C water was slightly higher than 40 °C. All subjects tolerated both bathing temperatures well for 1 h. Both 40 and 41 °C foot bathing for 1 h can increase the DPG and may be an effective way to affect whole body skin blood flow and trigger heat dissipation.