Marino's Clinical Reports

The purpose of this site is to provide a brief overview of selected medical topics, with emphasis on topics that are either controversial or not readily appreciated by the general public.

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Location: New York, New York, United States

Saturday, June 25, 2005

Oxygen Enriched Water-Buyer Beware

Although this is not a medical topic, it should be of interest to the legions of bottled water enthusiasts that populate this country. I have noticed in recent months that there are bottled water products that claim to be enriched or supercharged with oxygen. According to one manufacturer, this product will "give you the energy and boost you need during athletic activities". There's even an oxygen-enriched spray that you can squirt in your mouth for that instant energy rush.
Here's the problem: oxygen does not readily dissolve in water. This is the reason we need hemoglobin to carry oxygen in the blood (plasma is 93% water, and not enough oxygen can dissolve in plasma to meet the oxygen needs of aerobic metabolism). Let's see how much oxygen dissolves in water under normal conditions.

How Much Oxygen is in Water?
The volume of a dissolved gas in water can be calculated as the product of the gas pressure and the solubility coefficient for the gas in water. At room temperature, the solubility coefficient for O2 in water is 0.03 mL/L/mmHg. If the partial pressure of oxygen in the atmosphere is 150 mmHg, then one liter of water contains (0.03 x 150 = ) only 5 mLs of oxygen. The whole-body oxygen consumption of an average sized adult at rest is 250 mL/min, which means that for a person who is not active, the oxygen in one liter of water is enough to sustain metabolism for only 1.2 seconds! The situation gets much worse during exercise, where the oxygen consumption can increase 5 to 10-fold.

Is it Possible to Put More Oxygen in Water?
The manufacturers of these products claim they have a patented method for increasing the solubility of oxygen in water, but they give no information on this process, and there is nothing I can find in the scientific literature to support such a claim. Decreasing temperature will increase oxygen solubility in water, but the effect is extremely small. In fact, if there was a method to dissolve more oxygen in water, it could obviate the need for blood transfusions (simply give the oxygen-supercharged water instead). The scientist who discovers such a method would undoubtedly be a candidate for a Nobel Prize !

Thus, the notion of oxygen-enriched water is more fancy than fact, and products that make such claims are best left on the shelves of your grocery or pharmacy.