Oxygenated water has been a topic of interest for many years. Products appear on the market with impressive claims about health and performance. Most of it is pseudoscience, a lot of wishful thinking. There is not only no evidence, but also no plausible potential mechanism. Recently a scientific publication concluded that a new ‘oxygen-nanobubble beverage’ could improve performance by 2.4-7.1% (1). Dr Nick Tiller and I read the paper and were astonished (2)…
The oxygen-nanobubble beverage study
The study investigated the effect of an ‘oxygen-nanobubble beverage’ on physiology and performance in a small group of cyclists. The authors report a very large 2.4% improvement in performance in a 16.1-km time-trial, and an even larger 7.1% improvement in peak power output in a series of 30 second sprint tests. For someone who is really new in this area this may sound amazing and attractive. However, we must look more critically at the data and the conclusions.
Before we start buying oxygenated water (with or without nanobubbles), we must check a few things:
What does the literature say? Is this the only study, are there more studies?
Is there a plausible mechanism? Can this be expected to work?
Could there be other explanations for the findings of the study? Or in other words are the results caused by something other than oxygenated water?
Could there be a conflict of interest?
These are just some of the questions we should ask and we will discuss them below.
What does the existing literature say?
First, we must interpret this study in context. If this study confirms a large number of other studies, it is likely that it is a “real” finding. In that case of course, the finding would not really be “news”. However, if it contradicts other studies, the study results would have to be extremely convincing, to overturn the existing evidence. This new study contradicts a host of studies that found no effect of oxygenated water at all (3, 4, 5). The authors suggest that the observed effects are real, and thus they should provide very good evidence and very good reasoning why these results are different from the previous studies. The authors conclude that the oxygenated beverage “may provide a practical and effective ergogenic aid for competitive cyclists” but do not provide a satisfying explanation for their results. But is there a good explanation?
This new study contradicts a host of studies that found no effect of oxygenated water on exercise performance
Is there a plausible mechanism?
This brings us to the second questions we should ask: is there a plausible mechanism? If we give oxygen in a beverage, how is this supposed to improve performance? The authors argue that oxygen uptake is important for performance (and no one would argue against that), and they then provide oxygen in a drink.
Humans have lungs which are very effective at taking up oxygen from inspired air. The oxygen is taken up into the blood and transported around the body. A beverage will end up in the intestine (not the lungs; we advise strongly against putting a beverage in your lungs….). The authors argue that it is also possible to absorb some oxygen in the intestines and quote an animal study. But it is not just about whether it is possible (in some animals), it is whether it happens in humans and more importantly in what quantities. Studies with oxygenated water have not demonstrated that oxygen is taken up, have not demonstrated effects on oxygen consumption, and have not seen differences in either muscle or peripheral oxygen saturation during exercise. This study also shows no differences in any of the variables measured, so there is no evidence whatsoever that the oxygen from the beverage is taken up.
But even IF all oxygen in the beverage was taken up, there should be a lot of question marks. The drink was estimated to have provided ∼15 mL of oxygen. This is an inconsequential amount when contrasted against the oxygen inspired by the respiratory system. Indeed, from the cohort’s VO2peak of ∼57 mL/kg/min (∼4.2 L/min), we calculated that the 30-minute exercise bout at 60% VO2peak would have required about 75 L (75,000 mL) of inspired O2. A further ∼80 L (80,000 mL) would likely have been inspired during the subsequent 16.1-km time trial. The O2 provided by the beverage, assuming the full amount was successfully absorbed through the GI tract (an assumption that was not tested), represents just 0.01% of the O2 derived during exercise via the lungs.
The oxygenated water was estimated to have provided ~15mL of oxygen. This is an inconsequential amount when compared against the oxygen inspired by the respiratory system during exercise.
Expressed another way: if 1 L of O2 yields between 4.85 and 5.02 calories (depending on whether you burn more fat or carbohydrate), we can calculate that 15 mL of O2 yields just 0.073 − 0.075 calories, or 304–315 joules. This is the amount of energy we need to run 1 meter.
During 60 min of exercise (which is the approximate combined duration of the steady-state exercise bout and time trial), such an energy yield would equate to an additional 0.091 − 0.094 W, not 10 W as the authors reported during the time trial, and certainly not 63 W as was reported during the Wingate tests. The improvements in sprint performance are even less plausible because the sprints are largely independent of oxygen (anaerobic).
A long story short: there is no plausible mechanism (6).
Could there be a conflict of interest?
The study was commissioned and funded by Avrox—a prominent vendor of oxygen containing beverages. The fact that a company funds a study does not mean that the results are not valid, or we cannot trust the study. There are many great studies that were funded by companies. However, an additional warning sign is if the company exaggerates the claims on their web site (and they certainly do). This is just a red flag… which alongside the other red flags discussed above does not grow trust…
How did the authors end up with these results?
In our response to the paper we state that “we are not concerned that the data contradict the historical precedent—science thrives on debate and ongoing challenges to pre-existing norms. However, oxygenated beverages allegedly improve performance via a mechanism which is physiologically implausible”. The authors’ own data corroborate this speculation. The authors did not measure any change in any of the metabolic markers they measured. The only change was a change in performance.
Science thrives on debate and ongoing challenges to pre-existing norms. However, oxygenated beverages allegedly improve performance via a mechanism that is physiologically implausible.
This points at a belief effect. A placebo effect. Although a placebo effect is also an “effect”, this is not the result of oxygenated water. It is the result of a “belief”. The authors mention a potential placebo in one sentence and it is disappointing they did not expand this discussion, because it is the only plausible explanation for the results obtained.
Dr Nicholas B. Tiller is an exercise scientist and researcher at Harbor-UCLA.
Prof Asker E. Jeukendrup has over 30 years of experience as a sports nutrition researcher, educator, practitioner, and athlete.
Reference
King DG, Stride E, Mendis J, Gurton WH, Macrae H, Jones L, Hunt J. 2023. A double-blind, randomized, placebo-controlled pilot study examining an oxygen nanobubble beverage for 16.1-km time trial and repeated sprint cycling performance. J Diet Suppl. 1–15.
Hampson NB, Pollock NW, Piantadosi CA. 2003. Oxygenated water and athletic performance. JAMA. 290(18):2408–2409.
Leibetseder V, Strauss-Blasche G, Marktl W, Ekmekcioglu C. 2006. Does oxygenated water support aerobic performance and lactate kinetics? Int J Sports Med. 27(3):232–235.
McNaughton LR, Kenney S, Siegler J, Midgley AW, Lovell RJ, Bentley DJ. 2007. The effect of superoxygenated water on blood gases, lactate, and aerobic cycling performance. Int J Sports Physiol Perform. 2(4):377–385.
Piantadosi CA. 2006. “Oxygenated” water and athletic performance. Br J Sports Med. 40(9):740–741.
