A gas assisted re-breathing device is disclosed for life support of individuals venturing into harsh environments, particularly the underwater environment, which results in reduced work of breathing. Similar to prior art re-breathers, hoses connect a mouthpiece to direct the flow of breathing gas in a loop like fashion, passing in and out of a flexible gas storage container and a CO2 scrubbing device prior to re-breathing. Disclosed is a pressurized gas assisted re-breathing device, driven by pressurized gas, actuated by the breathing pressure local to the mouthpiece, that acts to move the flexible gas storage container on behalf of the individual and a loop seal valve that is forcibly shut during assisted breathing, which seals the assisted breathing loop to prevent premature venting of breathing gas to the surrounding environment, unless the assisted breathing loop is full, whereupon the loop seal valve opens to allow excess breathing gas to escape into the surrounding environment through forcible exhalation by the individual through one or more conventional one way valves that prevent backflow from the surrounding environment back into the loop. This device significantly reduces work of breathing without unwanted breathing gas loss and further facilitates additional safety features that would otherwise not be practical due to the resultant increase in work of breathing.