theory in support of oxygenated water as a training aid is the more oxygen that a person can consume, through any means, the more oxygen will be directed into the cells of the body. Once it enters the stomach, oxygenated water will be ingested through the small intestine. The cardiovascular system will transport the additional oxygen to the cells that need it, as with any other nutrient. As a result, the oxygenated water will enhance athletic performance, stamina, and overall energy levels, because the cells have more oxygen available to them to metabolize its energy stores.
A number of scientific studies conducted since the late 1990s concerning the benefits of oxygenated water have reached conclusions that counter the claims of the water manufacturers. All of these studies confirm the physiological proposition that oxygen carried into the stomach through the water consumed will not enter the bloodstream, as this oxygen will never pass beyond the membranes of the intestine. None of the studies conducted found any observable difference in the heart rate or overall cardiovascular function in persons using oxygenated water.
The American Council in Exercise was one research group to conclude that the only method by which oxygen could reach an energy-producing cell would be by way of the hemoglobin present in each erythrocyte, or by way of the tiny amounts that might be dissolved in blood plasma. Hemoglobin is the oxygen carrier present in every red blood cell. As the hemoglobin is at all times saturated with oxygen (as much 95% capacity) through the normal oxygen transport processes centered in the exchange mechanism situated in the alveoli, the tiny air sacs within the lungs, the oxygenated water has no delivery mechanism available to it.
Confirmation of the research critical of the oxygenated water industry claims is also supported, in a more oblique way, through the controversies regarding the illegal use of the hormone erythropoietin (EPO) by endurance athletes. EPO is the natural hormone that spurs the production of greater numbers of red blood cells to increase the body's oxygen-carrying capacity. The considerable body of science concerning EPO confirms that the only method by which oxygen capacity can be increased in an athlete is through increasing the number of erythrocytes available in the bloodstream.
While the athletic performance-enhancing claims made with respect to oxygenated water may be of questionable scientific validity, there is also the placebo effect of such products to be considered. Unlike many other sports supplements, pure water is not inherently harmful, and the consumption of oxygenated water is safe. The cost of these products aside, oxygenated water is a proper method with which to obtain the daily recommended water consumption levels. If the athlete believes that he or she is obtaining a physical advantage through the consumption of oxygenated water, the athlete may have created a personal psychological edge.