These days, you can find food and drinks with all kinds of things added intended to make us healthier. Orange juice fortified with calcium, breads and cereals with extra vitamins.
Now comes bottled water with extra oxygen. Marketers say this new breed of water can boost athletic performance and give you more energy.
Does it work?
One trial, published as a research letter in the Journal of the American Medical Association, shows that drinking bottled water described as “oxygenated” before exercise does not improve performance.
For the study, five brands of bottled water marketed for their high oxygen content were tested for the amount of oxygen per 100 milliliters of water and compared with the amount of oxygen found in well-stirred tap water.
Water was extracted from each bottle by inserting an airtight syringe into the side or cap of each bottle and pulling out the fluid.
As you can see in the table below, four of the five brands of oxygenated bottled water contained more oxygen than tap water, while the amount of oxygen in one brand was equivalent to that of tap water.
Of the five brands tested, the one with the highest oxygen content was used in the exercise phase of the study.
Eleven healthy adults (with an average age of 35 years) exercised on a stationary bicycle on two different days, at least three days apart. Five minutes before performing each exercise test, participants were asked to drink either oxygenated or ordinary water.
During exercise, there was no difference in any marker of exercise performance when subjects received oxygenated water rather than ordinary water.
To quote directly from the researchers:
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 plasma, it is not surprising that oxygenated water did not improve maximal exercise performance.
Researchers at the University of Wisconsin report very similar results. Their study included 12 college-aged men and women who were assigned to drink either 500-milliliters of “super oxygenated” water (Aqua Rush) or regular tap water.
During a multi-stage treadmill test, oxygenated water had no measurable effect on any of the variables measured during exercise or recovery.
“Once consumed, the water is absorbed into the bloodstream across the intestinal epithelium. It is highly likely that the cells in the gut consume the extra oxygen,” write the authors.
“Even if the oxygen did get absorbed, it would be absorbed into venous blood, where it is on it’s route back to the lungs for oxygenation, not to active muscle.”
The researchers also calculated that if AquaRush were to contain oxygen levels “ten times higher than the tap water you are drinking at home,” one 500-milliliter bottle would contain approximately 24 milliliters of additional oxygen.
However, the oxygenated water contained only three times as much oxygen as tap water (versus ten times as much, as claimed). This translates to only 6.7 milliliters of additional oxygen per 500-milliliter bottle.
It’s possible that some of the extra oxygen reportedly contained in the oxygenated water was lost while the product was on the shelf, or when the bottle was opened. However, all the bottles were analyzed immediately after opening. And it would be very difficult to drink the water without first opening the bottle.
In short, there’s very little evidence to show that oxygenated water has any significant effect on exercise performance, energy levels, or recovery.
Dr. Howard G. Knuttgen, Ph.D., professor emeritus of kinesiology at Penn State University describes oxygenated water as “a case of pure fraud without a physiologic foundation.”
“Very little oxygen can be forced into water under pressure — less than that contained in a single breath,” he adds.
“Most of the oxygen in the water would escape into the atmosphere when you open the container. Additional oxygen would be absorbed into the cells of intestinal walls. All of this would happen before any oxygen would reach the blood, much less the muscles.”
Anyone who claims that drinking oxygenated water before exercise is the same as increasing the oxygen content of the air you breathe is, in the words of Duke University Medical Center expert Dr. Claude Anthony Piantadosi, “conflating physics and physiology in a struthonian visit to placebo land.”