Effect of shoe color on shoe temperature and potential solar injury to the insensate foot.

The authors compared shoes of different colors in terms of the amount by which their temperature increased when subjected to radiant heat. Three trials of temperature measurements were performed for white and black leather walking shoes. A balloon filled with water was placed in the shoe and the surface temperature of the balloon was measured at baseline and after the shoe had been exposed to an infrared heat lamp for 15- and 30-minute periods. The results were significant: The mean increase in temperature after 15 minutes of exposure was between 4.0 degrees F and 8.8 degrees F greater in the black shoe than in the white shoe. After 30 minutes of exposure, the mean increase in temperature was between 7.8 degrees F and 13.6 degrees F greater in the black shoe than in the white shoe. This information can help prevent thermal injury to the insensate foot when shoes are worn in the sun for a prolonged period. Brief case reports of three patients who experienced such thermal injury are presented.