Blood oxygen levels refer to the amount of oxygen circulating in the blood. Normal blood oxygen levels fall between 75 and 100 millimeters of mercury (mm Hg) on arterial blood gas (ABG) test results.

If someone’s blood oxygen level falls below 60 mm Hg, there may not be enough oxygen reaching the body’s vital organs. This can lead to symptoms such as shortness of breath and dizziness. This article ...