95-100 percent.
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.  Normally, when your blood circulates to your lungs, 95 to 100 percent of your red blood cells are able to grab oxygen molecules, reports Harvard Health Publications. This is the normal oxygen level for an adult female and can be measured using a device known as a pulse oximeter. This is a small instrument that attaches to one of your fingers and is able to measure the amount of oxygen inside your blood in a non-invasive manner. Oxygen Saturation. The term oxygen saturation refers to the amount of oxygen your blood is carrying. When your blood circulates, it goes to each of your cells and picks up carbon dioxide, a byproduct of metabolism. Hypoxemia, or low blood oxygen, describes a lower than normal level of oxygen in your blood. In order to function properly, your body needs a certain level of oxygen circulating in the blood to cells and tissues. Though the pulse oximeter actually measures the saturation of oxygen in your blood, the results are often used as an estimate of blood oxygen levels. Normal pulse oximeter readings range from 95 to 100 percent, under most circumstances. Values under 90 percent are considered low. 1  Causes. Normal Blood Oxygen Levels. Healthy people have a normal range of oxygen saturation from 95% – 100%, although levels down to 90% are common and not usually cause for alarm. During exercise, the increased oxygen consumption may reduce blood saturation, but the increased breathing rate and blood flow compensate for this. Oxygen saturation is measured by a pulse oximeter, a device placed on the finger that uses light absorption to indicate the level of saturated hemoglobin, the protein on the red blood cell that stores oxygen during transport. Oxygen levels can also be determined through a blood test called an arterial blood gas, or ABG Oxygen is necessary to sustain your life. The normal oxygen levels between women and men do not vary; oxygen is needed equally by both genders. However, the factors that influence your body's ability to take in and carry oxygen may be affected by your gender. Oxygen Saturation. The term oxygen saturation refers to the amount of oxygen your blood is carrying. When your blood circulates, it goes to each of your cells and picks up carbon dioxide, a byproduct of metabolism. This measurement is called an arterial blood oxygen. A normal arterial blood oxygen level typically falls between 75 and 100 mmHg. Your blood carbon dioxide level and pH -- a measure of acidity or alkalinity -- are usually measured along with the arterial blood oxygen level. A pulse oximeter uses light to measure the oxygen saturation level, the percentage of hemoglobin in your red blood cells carrying oxygen. Normal oxygen saturation levels fall between 95 and 99 percent. 1 The level of oxygen in airplanes is about the same as the oxygen level at an elevation of 8000 ft (2400 m) . 2  This drop in oxygen can really affect people with COPD. 3  If you normally use oxygen or have borderline-low oxygen levels in your blood, you may need oxygen when you fly. Oxygen can also be used at home if the oxygen level in your blood is too low for long periods. Long-term oxygen therapy should be used for at least 15 hours a day with as few interruptions as possible. Regular use can reduce the risk of death from low oxygen levels. Cigarette smoke contains carbon monoxide, which competes with oxygen on the hemoglobin of the red blood cell. Because hemoglobin saturated with CO (carbon monoxide) can not be differentiated from that with oxygen, a pulse oximetry test may indicate the blood level is normal, when in fact the oxygen levels are low. Oxygen saturation is measured by a pulse oximeter, a device placed on the finger that uses light absorption to indicate the level of saturated hemoglobin, the protein on the red blood cell that stores oxygen during transport. Oxygen levels can also be determined through a blood test called an arterial blood gas, or ABG
https://en.wikipedia.org/wiki/Oxygen_saturation_(medicine) http://www.livestrong.com/article/456711-what-is-a-normal-oxygen-level-for-an-adult-female/ http://www.mayoclinic.org/symptoms/hypoxemia/basics/definition/SYM-20050930 http://www.3fatchicks.com/what-is-a-normal-resting-blood-oxygen-level/ http://www.livestrong.com/article/456711-what-is-a-normal-oxygen-level-for-an-adult-female/ http://www.livestrong.com/article/124374-normal-range-blood-oxygen-level/ http://www.webmd.com/lung/copd/oxygen-treatment-for-chronic-obstructive-pulmonary-disease-copd http://www.3fatchicks.com/what-is-a-normal-resting-blood-oxygen-level/
what is normal oxygen levels