The basic problem in free diving lies in loss of consciousness that may happen because of failing in the brain compensatory abilities of adaptation (occurring) on the background of a certain load, which is inadequate to its reserved possibilities. It happens due to some combination of high level of metabolic activity of the cerebrum cells, allow storage of oxygen and small reserve of high energetic phosphates, whereas the muscles contain myoglobin which incorporates oxygen six times faster than hemoglobin does reduction of adenosine triphosphoric acid.