Our bodies receive oxygen from the air we breath. In our lungs, this oxygen moves across thin membranes and enters the bloodstream. Oxygen is bound to special molecules on red blood cells called hemoglobin, which let it travel in the blood to the tissues that need it. The amount of oxygen in the blood is an indication of several health factors, and falls within a normal range.
Types of Tests
There are two tests for measuring the oxygen saturation in your blood. One involves placing a small clip type of device on your finger. A special light inside the clip shines through your finger. This light travels differently through those blood cells that are carrying oxygen and those that are not. By interpreting the way the light shines through your blood, the machine is able to estimate the amount of oxygen your blood is carrying.
Another method is called the arterial blood gas test, and involves inserting a needle into an artery, most often one in your wrist. A small blood sample is drawn from your artery, and special tests are performed on it to determine the oxygen levels.
Normal Range
The heart pumps blood past the lungs, and there the hemoglobin in your blood cells can pick up oxygen molecules. When a blood cell is carrying a normal load of oxygen, it is said to be "saturated." Optimally, 95 to 100 percent of your blood cells are saturated with oxygen, according to the Harvard Medical School. The Mayo Clinic states that oxygen blood levels below 90 are considered low.
Causes of Low Levels
Low oxygen saturation levels can be caused by a number of physical issues. Diseases or conditions that interfere with the heart's ability to move blood, or with the respiratory system's ability to deliver oxygen to the blood, are most often the cause of low blood oxygen levels, according to the Mayo Clinic. These include emphysema, asthma, pneumonia, shock and low cardiac output.
Symptoms of Low Levels
Symptoms of low blood oxygen levels include shortness of breath, fatigue and the inability to tolerate exercise. Additionally, mental confusion may indicate that the brain is not receiving the oxygen it needs.
Achieving Normal
Maintaining or achieving a normal level of blood oxygen may involve seeking treatment for an underlying medical condition. The Harvard Medical School states that if you have chronic medical conditions, your body may learn to adjust to lower levels and your blood oxygen levels may normally be low. To remedy low blood oxygen levels, the Mayo Clinic advises avoiding second-hand smoke and to quit smoking. Additionally, exercise can help strengthen your respiratory and cardiovascular systems and boost your blood oxygen levels.
