Generally speaking, patients with hypoxic symptoms such as chronic obstructive pulmonary disease, bronchiectasis, bronchial asthma and cor pulmonale are advised to receive oxygen therapy 15 hours or more every day.
Health care friends can take oxygen according to the doctor's advice, or for several hours a day.
For friends with sleep apnea and chronic respiratory failure, it will be better if they are treated with non-invasive ventilator and oxygen generator.
Image source: Kangshang oxygen generator