The present invention provides an oxygen control system for supplying a predetermined rate of flow from an oxygen source to a person in need of supplemental oxygen comprising an input manifold, an output manifold and a plurality of gas conduits interconnecting the input manifold to the output manifold. The oxygen source is arranged in flow communication with the input manifold, and a needle valve is positioned in flow control relation to each of the conduits so as to control the flow of oxygen from the input manifold to the output manifold. A plurality of solenoid valves, each having a first fully closed state corresponding to a preselected level of physical activity of the person and a second, fully open state corresponding to another preselected level of physical activity of the person, are positioned in flow control relation to all but one of the conduits. Sensors for monitoring the level of physical activity of the person are provided, along with a control system that is responsive to the monitored level of physical activity, for switching the solenoids between the first state and the second state. A method for supplying supplemental oxygen to a person according to the level of physical activity under taken by that person is also provided.