I’m taking a summer blogging break and recovering from a badly sprained ankle. This week I’m slightly revising an old post. See you in September!
My exercise of choice is running, which I do several times per week. My summer fitness plans came crashing to a halt in July when I badly sprained my ankle (ironically, not running, but walking). I quickly moved from “middle-aged athlete” to “angry, injured ex-athlete”. I was looking for anything that might help me recover more quickly. The physician suggested physiotherapy, so I booked an appointment at my local sports medicine clinic. And with that I entered a world where it’s tricky to tell the difference between science and pseudoscience.
I’ve never sprained my ankle before, and many people told me horror stories – “It will never be the same again” I was warned. So I went to the local sports medicine clinic, wanting to apply the best science to heal my ankle and recover full function. In the waiting room there was a display of Kinesio Tape for sale. Brochures invited me to consider acupuncture for my injuries. And I could have booked time with a chiropractor if wanted. I didn’t want any of that. I wanted evidence-based advice and treatment. The physiotherapist I’m working with seems evidence-based, and despite his recommendation of acupuncture (and quite possibly the occasional use of ultrasound), the work we’ve been doing seems reasonable and conservative. While I’m not limping anymore, the pain isn’t gone yet, and I’m even allowed to do some gentle “jogging” on flat surfaces again.
Leaving the clinic after my second visit, in slightly less pain, I noted that this clinic also sold bottled water. But it wasn’t just any bottled water. This water was specifically for athletes. The label caught my attention and I snapped a picture (above). I had never heard of water with extra oxygen before, with the exception of when I blogged about hydrogen peroxide. Based on the marketing for this particular product, GP8, some athletes endorse oxygenated water, claiming that they can perform better. There are dozens of water products that claim to deliver more oxygen with each swallow, and they’re sold widely.
“GP8 Oxygen water improves oxygen delivery through the circulatory system by promoting more efficient oxygen transfer through the plasma resulting in advanced hydration.”
– Product advertisement
I can see why this product would be tantalizing to anyone that wants an athletic edge or faster recovery. When you’re injured, there can be a strong feeling of “what’s the harm” that can overwhelm any cautious consideration of the science and the evidence. It’s the same reason that dietary supplement vendors are sponsoring Olympic athletes, and why many athletes endorse these products despite the lack of evidence that they provide any meaningful benefit. Athletes want any edge they can get, even if it’s pseudoscience. Anything that can help performance (or perhaps recovery from injury) can seem very attractive. What better setting could there be to market these products than a clinic treating injured athletes?
Despite the hype, the claims and the athletic endorsements, there’s no persuasive evidence that oxygenated waters offer any meaningful health or athletic benefits beyond the basic hydration you can get from a tap. Like many pseudoscientific products, oxygenated water in an unsinkable rubber duck.
Who drinks oxygen, anyway?
Why would we drink oxygen at all? We’ve all got unlimited access to air, which at about 21% oxygen keeps our bloodstream almost completely saturated with oxygen. I can only postulate the reasoning behind the development of these products:
- We need oxygen to live
- When we exercise, we sometimes get short of breath
- If some oxygen is good, then more must be better
- “Hey guys, I’ve got an idea. What if we cram more oxygen in drinking water? Then we can bypass the lungs and put more oxygen in the bloodstream.”
- Profit (and perhaps get a supportive anecdote)
It’s true that we need oxygen to live, and when we breathe heavily during exercise, it’s to take in more oxygen and eliminate carbon dioxide (CO2). Almost of the oxygen the blood carries is bound to hemoglobin. There’s a small amount of oxygen that’s dissolved in the plasma. When we exercise, the amount of oxygen in the blood decreases only slightly, from nearly 100% saturation to around 90%. Under most circumstances, the air we breathe is providing all the oxygen we need – exceptions being specific medical conditions, or breathing at very high altitudes, where air pressure is lower and the oxygen saturation in the blood is lower, too.
While there’s an oxygen atom in every water molecule, this isn’t “free” oxygen that is available for respiration. There’s a small amount of oxygen (as O2) that’s dissolved in water and available to aquatic life. Putting water under pressure, you can force more oxygen to dissolve into it. But release the pressure, and you’ll see it emerge – it’s the same principle as carbonated water, where CO2 is released when a no longer under pressure.
The manufacturer of the bottled water I spotted in the clinic claims to have solved this issue:
GP8’s Enhanced Solubility Water contains up to 400% as much dissolved oxygen as untreated water. This oxygen occurs in the form of ‘guest’ molecules of O2 which occupy and stabilize the spaces between molecules of H2O. The unique purification process used to create GP8 results in larger spaces between H2O molecules, which in turn allow for two or more molecules of O2 occupying and stabilizing them. The result is increased oxygen content. And unlike ‘oxygenated waters’ which quickly release their dissolved gas after opening, the oxygen in GP8 is not under pressure and remains in the water for several hours, even with agitation. GP8 is believed to improve oxygen delivery through the circulatory system by promoting more efficient oxygen transfer through the plasma. Not only does GP8 maximize oxygen intake, but it is also one of the few alkaline pH waters available – a property which is thought to help counter the effects of lactic acid. Committed to serious athletes, GP8 Oxygen Water is 100% additive-free and contains no chemical by-products resulting from the purification process.
There’s about 5mg/L of dissolved oxygen in typical drinking water, but that can vary based on the source, the temperature and other factors. The proprietary method claimed by GP8 states that it can increase the effective oxygen levels without putting the water under pressure. While there’s an elaborate information sheet posted online, I can’t find any published evidence to show that (1) this phenomena actually exists and that (2) there’s actually more oxygen absorbed through the gastrointestinal tract.
Our need to use oxygen at elevation tells you what happens if we happened to absorb oxygen into our bloodstream. Without putting the body under higher atmospheric pressure, the blood can’t simply dissolve more oxygen in it when it’s already saturated.
The manufacturer of GP8 has a list of several studies that they assert support their claim of effectiveness. I can’t find any that have been published and peer reviewed. And there’s insufficient information presented to even evaluate the data. Here’s one example:
Study ESW 002: Single-Blind, Randomized, Tap Water Controlled, Sub-Maximal Exercise Test at a Predetermined Heart Rate to Ascertain the Effect of Enhanced Solubility Water (ESW) on Cycling Speed Over a Five-Mile Simulated Distance
Study site: NorCal Bicycle Testing Facility, Santa Rosa, CA
The results showed that after consuming ESW, the cyclists, while maintaining their pulse rates constant, were statistically significantly faster for miles 2-5 and for the full five mile course (P < 0.05), than after ingesting [tap water]. Since Studies ESW 001 and ESW 002 demonstrated markedly positive physiologic effects of ESW, a larger more definitive study was performed.
In order for the claims of oxygenated waters to be considered credible, there needs to be rigorously controlled trials (double-blind) with an appropriate number of test subjects. The entire methodology needs to be well documented, and it needs to be published in peer-reviewed literature. For more credibility, it needs to be duplicated. The fact that there’s no credible, published, peer-reviewed literature showing that oxygenated water delivers any athletic benefits is telling. Probably most importantly, even if there is more oxygen in oxygenated water, and it actually is absorbed, it won’t matter. The amount of oxygen in just one breath is vastly higher than the theoretical oxygen supplied by any oxygenated water.
Conclusion: Snake oil, without the snake or the oil
Like homeopathy, which promises all the benefits of medicine without the actual medicine, or sports supplements that promise “drug free” enhancement of athleticism, oxygenated water promises a sports advantage with zero downside. If I didn’t examine the evidence, I could probably be convinced that oxygenated water might help me be a better athlete. Given it is water, what’s the harm? But it is when we are most desperate that we are at our most vulnerable. It’s hard to be objective, to ask for the evidence, and to critically appraise it. But that’s when it’s probably most important. As I am constantly reassuring myself these days, when we see the promise of a magical quick fix, we need to be extra skeptical.