Respiration supplies the oxygen needed for energy usage and removes the carbon dioxide one of the waste products of energy consumption. Energy homeostasis is maintained through interacting networks that control food intake, energy usage and the sleep/wake cycle. Adipose tissue mass changes when energy gain s and losses are no longer in balance. But adipose tissue is not passive and through the release of chemical messages affects energy homeostasis. The chemical messages involved in energy homeostasis also can modify the performance of the respiratory system not just in sleep but in wakefulness as well.