Blood oxygen levels help indicate lung health, as well as other conditions that happen in the body. Learn more about normal blood oxygen levels here.

Normal Ranges Most people have a normal resting pulse oximetry reading for oxygen saturation (SpO2) between 95% and 100%. This shows that your blood has an appropriate amount of oxygen.

What is a good oxygen level? “Normal people who have working lungs, and all those steps are going well, their blood oxygen level will usually be 96-100 percent,” adds Dr. Uppal.

The team reported the mice in the oxygen-restricted environment lived about 50% longer than the mice in normal oxygen levels, with a median lifespan of 23 weeks compared to 15 weeks.

When oxygen supplies are low, most cells can survive because they adapt, by changing which proteins they make, to produce energy through different processes than in normal oxygen levels.