Your blood oxygen level measures how well your lungs are able to move oxygen through the blood, and in turn remove carbon dioxide from the blood. Using a home testing device, you can quickly check your blood oxygen level to make sure it is neither too high nor too low. Having an oxygen level that's too high or too low can make you very sick, and can even lead to death.
First, purchase a blood oxygen level meter. These can be found online at many health retailers or at some outdoor sporting goods retailers.
Place any batteries needed into the meter, and turn on the device.
Place the blood oxygen level meter on your index finger. Your finger should fit into a slot on the device snugly and your fingertip should be flat on the meter.
Push the "read" button to have your blood oxygen level taken. Wait three to five seconds for the meter to take the level.
The results will show up on a small screen on the device. Make a note of it, and repeat the process if necessary.