An apparatus and method for metabolic cooling and insulation of a user in a cold environment. In its preferred embodiment the apparatus is a highly flexible 
composite material having a flexible matrix containing a 
phase change thermal 
storage material. The apparatus can be made to heat or cool the body or to act as a thermal buffer to protect the wearer from changing environmental conditions. The apparatus may also include an external 
thermal insulation layer and / or an internal 
thermal control layer to regulate the rate of heat exchange between the composite and the 
skin of the wearer. Other embodiments of the apparatus also provide 1) a path for 
evaporation or direct absorption of 
perspiration from the 
skin of the wearer for improved comfort and 
thermal control, 2) heat conductive pathways within the material for thermal 
equalization, 3) surface treatments for improved absorption or rejection of heat by the material, and 4) means for quickly regenerating the thermal storage capacity for reuse of the material. Applications of the composite materials are also described which take 
advantage of the composite's thermal characteristics. The examples described include a diver's wet suit, ski boot liners, thermal 
socks, gloves and a face 
mask for 
cold weather activities, and a metabolic heating or cooling 
blanket useful for treating 
hypothermia or fever patients in a 
medical setting and therapeutic heating or cooling orthopedic joint supports.