<P> Oxygen saturation is 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 ( O ) 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 . </P>
<P> Oxygen saturation is 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 ( O ) 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 . </P>
what is the normal oxygen level in the human body
what is the normal oxygen level in the human body
95 -- 100 percent
95 -- 100 percent