The characteristic of Oxygen Multistep Therapy is the long-lasting improvement of the energetic or oxygenation state of the organism. This specific effect is confirmed with statistical significance by a two-centric double-blind study on 20 male healthy volunteers from the working population. In this study the ergometrically measurable increase of physical fitness, which was determined two weeks after performance of two 15 min-oxygen-multistep-quick processes, served as over-all criterion. The mean value of the continuing elevation was 17%. On individuals having initially lower physical capacities and therefore being particularly in need of treatment, increases of 25, 33, and even 45% were determined.