The present invention describes systems and methods to provide variable flow oxygen therapy. An exemplary embodiment of the present invention provides a method of oxygen therapy involving delivering oxygen-enriched gas to a patient during a first portion of a breathing cycle at a first flow rate. Furthermore, the method of oxygen therapy involves delivering oxygen-enriched gas to the patient during a second portion of the breathing cycle at a second flow rate, where the second flow rate is greater than zero and less than the first flow rate.
