Abstract: An adaptive thermodynamic therapy system capable of comfortably increasing metabolic expenditure to facilitate excess weight loss, including one or more sensors for measuring a subject user's body temperature, current activity/metabolic level and providing data representative of said body temperature to a computer-based controller, and then actively controlling a thermal load in contact with subject user's body and responsive to the computer-based controller. In one embodiment, the controller is configured to receive input from at least one computer-based device configured to provide user body data and calculate a state value representative of the user body data and to adjust the thermal load to obtain a desired physiological response from the user by modifying the state values.