During periods of rest the standard breathing volume for a healthy person is between 4 and 6 liters of air per minute, which results in almost complete oxygen saturation of 95 to 99 percent. Because oxygen is continually diffusing from the blood into the cells, 100 percent saturation is not always feasible. An oxygen saturation of 100 percent would suggest that the bond between red blood cells and oxygen molecules is too strong, reducing the blood cells’ ability to deliver oxygen to muscles, organs, and tissues.
