Oxygen saturation is a term referring to the fraction of
oxygen-saturated hemoglobin relative to total hemoglobin (unsaturated + saturated) in the
blood. The human body requires and regulates a very precise and specific balance of oxygen in the blood. Normal
blood oxygen levels in humans are considered 95-100 percent. If the level is below 90 percent, it is considered low resulting in
hypoxemia. Blood oxygen levels below 80 percent may compromise organ function, such as the brain and heart, and should be promptly addressed. Continued low oxygen levels may lead to respiratory or cardiac arrest.
Oxygen therapy may be used to assist in raising blood oxygen levels. Oxygenation occurs when
oxygen molecules enter the
tissues of the body. For example,
blood is oxygenated in the
lungs, where oxygen molecules travel from the air and into the blood. Oxygenation is commonly used to refer to medical oxygen saturation.