A research letter was published in the Journal of the American Medical Association 11/12/2003 (Hampson et al., 2003). The focus of the research was to determine what if any potential benefits these “oxygenated” bottled waters could provide regarding enhanced sports performance. The results, although not diving-specific, can be correlated with diving. Please read the following concluding comments:
“Of five tested brands of oxygenated water, four contained more oxygen than tap water, but their oxygen content was not great because oxygen is relatively insoluble in water. The highest contained 80 mL of oxygen in a typical 12 ounce bottle.
However, air is 20.9% oxygen, and a normal human tidal breath of roughly 500 mL contains 100 mL of oxygen. Thus, a single breath of air contains more oxygen than a bottle of oxygenated water. Given that hemoglobin is already nearly saturated with oxygen during air breathing, and that only a small amount of additional oxygen can be dissolved in the plasma, it is not surprising that oxygenated water did not improve maximal exercise performance. Furthermore, given the small amount of oxygen in bottled water compared with that in air, any benefit would be quite brief.”
As a separate point, consuming oxygenated water on the surface likely poses no oxygen hazard for diving. The relatively small volume of high oxygen content water is introduced through the stomach. The same concentration would not reach the bloodstream.