An Oxygen Flow Control Unit (OFCU) configured to provide a closed loop oxygen supply system for maintaining a subject's blood oxygen level, the OFCU comprising: a manifold supporting two valves: a control valve controlling oxygen flow during normal operation of the OFCU, and an automatic bypass valve being normally closed, wherein, in the event of a systemic malfunction, the automatic bypass valve opens completely; an oxygen tank fluidly connected to an oxygen regulator configured to reduce the oxygen pressure to 34-241 kPa (5-35 psi), the regulator fluidly connected to an oxygen inlet port of the manifold; a computing device comprising at least one processor electrically connected to a valve controller and to a power regulator; one or more communication devices connecting the computing device to one or more sensors; a plurality of modules executable by the at least one processor, the modules comprising: a data input module configured to record a subject's target blood oxygen level; a sensor input module configured to: record a subject's actual blood oxygen level, and calculate a difference between the subject's actual blood oxygen level and the subject's target blood oxygen level; a control module configured to: instruct the valve controller to increase oxygen flow from the oxygen inlet port of the control valve to an oxygen outlet port of the control valve when the subject target blood oxygen level is less than subject's lower threshold desired blood oxygen level; instruct the valve controller to decrease oxygen flow from the oxygen inlet port to the control valve to an oxygen outlet port of the control valve when the subject's target blood oxygen level is greater than subject's upper threshold blood oxygen level; and a regulated oxygen delivery system fluidly connected to the oxygen outlet port of the control valve. a manifold supporting two valves: a control valve controlling oxygen flow during normal operation of the OFCU, and an automatic bypass valve being normally closed, wherein, in the event of a systemic malfunction, the automatic bypass valve opens completely; an oxygen tank fluidly connected to an oxygen regulator configured to reduce the oxygen pressure to 34-241 kPa (5-35 psi), the regulator fluidly connected to an oxygen inlet port of the manifold; a computing device comprising at least one processor electrically connected to a valve controller and to a power regulator; one or more communication devices connecting the computing device to one or more sensors; a plurality of modules executable by the at least one processor, the modules comprising: a data input module configured to record a subject's target blood oxygen level; a sensor input module configured to: record a subject's actual blood oxygen level, and calculate a difference between the subject's actual blood oxygen level and the subject's target blood oxygen level; a control module configured to: instruct the valve controller to increase oxygen flow from the oxygen inlet port of the control valve to an oxygen outlet port of the control valve when the subject target blood oxygen level is less than subject's lower threshold desired blood oxygen level; instruct the valve controller to decrease oxygen flow from the oxygen inlet port to the control valve to an oxygen outlet port of the control valve when the subject's target blood oxygen level is greater than subject's upper threshold blood oxygen level; and a regulated oxygen delivery system fluidly connected to the oxygen outlet port of the control valve. a data input module configured to record a subject's target blood oxygen level; a sensor input module configured to: record a subject's actual blood oxygen level, and calculate a difference between the subject's actual blood oxygen level and the subject's target blood oxygen level; record a subject's actual blood oxygen level, and calculate a difference between the subject's actual blood oxygen level and the subject's target blood oxygen level; a control module configured to: instruct the valve controller to increase oxygen flow from the oxygen inlet port of the control valve to an oxygen outlet port of the control valve when the subject target blood oxygen level is less than subject's lower threshold desired blood oxygen level; instruct the valve controller to decrease oxygen flow from the oxygen inlet port to the control valve to an oxygen outlet port of the control valve when the subject's target blood oxygen level is greater than subject's upper threshold blood oxygen level; and a regulated oxygen delivery system fluidly connected to the oxygen outlet port of the control valve. instruct the valve controller to increase oxygen flow from the oxygen inlet port of the control valve to an oxygen outlet port of the control valve when the subject target blood oxygen level is less than subject's lower threshold desired blood oxygen level; instruct the valve controller to decrease oxygen flow from the oxygen inlet port to the control valve to an oxygen outlet port of the control valve when the subject's target blood oxygen level is greater than subject's upper threshold blood oxygen level; and a regulated oxygen delivery system fluidly connected to the oxygen outlet port of the control valve.