Smart Heating Sleeping Bags Improved Human Local Thermal Comfort at the Feet

To improve local thermal comfort at feet, a smart heating sleepingbag (MARHEA) was developed by inserting two heating pads into a traditional sleepingbag (MARcoN) at the feet region. Human tests were conducted to examine the effect of MARHEA in improving local thermal comfort under cold exposure. Eight subjects including four females participated in this study. The duration of each test was 3 h and all tests were performed in a climate chamber where the air temperature was -0.4 degrees C (Comfort temperature for females) and -6.4 degrees C (Limit temperature for males), respectively. The relative humidity was 45 +/- 5% and the air velocity was set at 0.5 +/- 0.1 m/s. The main findings indicated that the MAR(HEA) could maintain the toe and feet temperatures within the thermoneutral range for both females and males compared to the linearly decreased temperatures in MARcoN. Thermal and comfort sensations in the feet as well as in the whole body were improved for females and males in MARHEA compared to MARcoN. It was concluded that MARHEA is effective in improving the local thermal comfort at the feet.