Body support systems (10) such as mattresses include breathing layers (22, 28, 34) that define internal air flow guides and form part of the structure for pressure redistribution. At least one air flow unit is coupled for fluid communication with the breathing layers (22, 28, 34) so that heat and moisture may be drawn away from an uppermost comfort layer (22) or body-supporting layer, through the breathing layers (22, 28, 34), and exhausted out of the body support system. Alternatively, air may be directed through permeable portions of the layers of the body support system (10) to the uppermost layer (22), particularly at the torso supporting region.
