Fig. 1
Schematic diagram depicting the distribution of oxygen bound to hemoglobin and dissolved oxygen in blood vessels under normobaric (a) and mild hyperbaric oxygen (b) conditions. Abundant hemoglobin is distributed in red blood cells, and up to four oxygen molecules can bind to one hemoglobin (oxygen bound to hemoglobin). The other kind of oxygen is dissolved in blood plasma (dissolved oxygen). The quantity of dissolved oxygen is less than that of oxygen bound to hemoglobin. Enhanced atmospheric pressure and/or oxygen concentration can increase oxygen in the body, especially dissolved oxygen in blood plasma. In addition, dissolved oxygen is able to flow to the peripheral cells, especially those in the brain, heart, and eyes, even if capillaries are very narrow, since it is dissolved directly in blood plasma