respiratory burst involved in defense response respiratory burst after phagocytosis oxidative burst after phagocytosis metabolic burst after phagocytosis GO:0045728 A phase of elevated metabolic activity, during which oxygen consumption increases, that occurs in neutrophils, monocytes, and macrophages shortly after phagocytosing material. An enhanced uptake of oxygen leads to the production, by an NADH dependent system, of hydrogen peroxide (H2O2), superoxide anions and hydroxyl radicals, which play a part in microbiocidal activity.