Depending on your individual oxygen therapy needs, your doctor may determine that you need to use oxygen therapy while you are sleeping. It might be necessary for you to receive oxygen therapy 24/7, or just during the night, because you might have a hard time bringing in enough oxygen on your own while you are sleeping. A different dosage setting might even be needed while you are sleeping, as opposed to the setting you use while you are awake.
Your doctor might do an overnight sleep study to monitor your blood oxygen levels during the night, when you wake up in the morning, and compare them to your blood oxygen levels while you are awake. He or she will prescribe night time use and specify on a dosage setting specific to your individual needs.