Exercise oximetry is used to check the oxygen level of your blood at rest and as you walk on a treadmill. The test is done to see if oxygen therapy is needed for certain activities or how much oxygen should be used for these activities.
For this test, a small sensor similar to a clip-on earring is placed on your finger or earlobe. Then using light waves the oxygen level in the blood is measured. Exercise oximetry takes about 30 minutes.