Hemorrhage reduces availability of oxygen and substrates and stimulates a switch to anaerobic metabolism leading to decreased ATP synthesis and subsequent heat production. This cellular hypoxia also stabilizes HIF-1, which activates several inflammatory and apoptotic pathways leading to increased cell injury and death. ATP = Adenosine Tri-Phosphate. ADP = Adenosine Di-Phosphate. HIF-1 = Hypoxia-Induced Factor-1. iNOS- induced Nitric Oxide Synthase. NO = Nitric Oxide. PG = Prostaglandin. NF-kB = Nuclear Factor- kappa B. COX-2 = cyclo-oxygenase-2. IL = Interleukins. TNFα = Tumor Necrosis Factor alpha. G-CSF = Granulocytes Colony Stimulating Factor. STAT = Signal Transducers and Activators of Transcription.