Abstract: A body heating/cooling apparatus includes a vest having a front panel and a back panel defining a cavity therebetween. A flexible, continuous channel is disposed in serpentine fashion throughout the cavity and has adjacent portions. An inlet and an outlet are provided for infusing a fluid into the channel and for withdrawing the fluid from the channel. The adjacent portions of the channel are placed in fluid communication by passageways extending between corresponding adjacent portions at locations intermediate the ends of the adjacent portions. The passageways are configured with respect to the corresponding adjacent portions such that substantially all of a fluid flowing through the corresponding adjacent portions normally bypasses the passageways.