Two weeks ago, in the audio podcast with Alex Tarris “Shattering The Myths Of Detox Therapy, Infrared Saunas, Health Scams & More”, we discussed both hypoxia (low oxygen availability) and hyperoxia (high oxygen availability) and the therapeutic and performance-enhancing benefits of both of these strategies.
After I released that particular episode, I had an interesting conversation with my friend Dr. Johnathan Edwards, who is an endurance athlete, private practice anesthesiologist, physiologist and sports medicine physician based in Las Vegas, Nevada. Since Dr. Edwards consults with many professional athletes in many different disciplines in North America and Europe, including cyclists in the Tour de France, AMA motocross athletes and UFC fighters, I was specifically curious to hear his opinion on “how much oxygen is too much” and “how little oxygen is too little”.
In other words, if you use something like a hyperbaric oxygen therapy chamber or some other form of concentrated oxygen, can you do to much of it to the point where it becomes damaging to your brain or body?
And the same goes for hypoxia: if you overdo something like elevation training, an altitude tent, or a hypoxic air generator, could you also hurt your health or your performance gains?
So in today's article, written by Dr. Edwards with some editing and additions by yours truly, you're going to discover the truth about oxygen therapy, altitude training, hypoxia, biohacking elevation, how much oxygen is too much and how much oxygen is too little. Enjoy.
Supplemental Oxygen Therapy: What You Need To Know
You often see NFL players on the sidelines breathing oxygen, and you may wonder whether breathing that high concentration of oxygen through a special mask is actually helping them to recover faster, or perhaps it's just a placebo.Though a colorless, odorless gas that is poorly understood by most doctors and sports practitioners, oxygen is essential to life, it is in 21% of every breath you take, and, believe it or not, supplemental oxygen is actually regulated as a prescription drug in the U.S. by the FDA.
In people with lung disease, supplemental oxygen clearly has many beneficial effects that have been proven in clinical studies. Even in the absence of disease, supplemental oxygen, such as is found in a hyperbaric oxygen therapy chamber or some of the other oxygen delivery tools you'll learn about later in this article, can also help regular non-diseased people (and athletes) with wound healing, tissue repair, recovery, fighting inflammation, mental acuity, increased exercise capacity, and much more.
But due to complicated and erroneous things taught in medical school, along with some cloudy ideas about sick people and supplemental oxygen somehow inducing “free radical formation”, many physicians and laypeople have a mistrust of oxygen. And it's true: there are some very important things to consider when administering oxygen, since it is possible to give too much oxygen as well as too little.
Many scientists don't believe it's possible to increase the oxygen in your blood by breathing supplemental oxygen or by using a hyperbaric oxygen chamber.
But they're wrong, and here's why.
Oxygen is contained in the blood in two forms:
(1) dissolved in plasma, which is about 2% oxygen;
(2) bound to hemoglobin in red blood cells, which is about 98% oxygen.
Breathing supplemental oxygen saturates the hemoglobin and increases the concentration of dissolved oxygen in plasma. As an example, one of the really neat procedures I do as an anesthesiologist is to perform something called pre-oxygenation (also known as de-nitrogenation) on patients before they undergo general anesthesia.
Using a mask system, I administer 100% oxygen for 3 to 5 minutes, and then induce general anesthesia. Assuming the patient is relatively healthy, the patient's oxygen saturation will stay at 100% without a single breath for up to 5 minutes, and without harming the patient or causing excessive free radical formation. This is possible is because the concentration of oxygen in the plasma is maximized. In many cases, very high concentrations of oxygen can be given throughout the entire operation.
When it comes to athletic performance, studies are mixed about whether supplemental oxygen actually helps. For example, I work with many professional cyclists and UFC fighters who use supplemental oxygen, particularly when they are training at higher altitudes.Whether or not you believe that oxygen is beneficial, many of these athletes “feel” that it works for them. Oxygen has indeed been shown in studies to positively affect power, but apparently not VO2 max (your maximal consumption of oxygen) )(1, 2, 3).
At high altitude, we do know that supplemental oxygen increases work capacity, and may also reduce perceived exertion (1,2, 4, 5). At sea level, the effect of supplemental oxygen is less clear, although I have athletes report that it helps reduce their rating of perceived exertion while performing high-intensity intervals. It's apparent that it is not all about getting more oxygen to the tissues, and that other things are happening when you use supplemental oxygen. The leading theories include effects on pulmonary, cardiac, and acid-base physiology (3, 6, 7).
It is theoretically possible get too much oxygen, but rest assured that it is nearly impossible to do while on land. Problems from oxygen toxicity occur most often in hospitalized patients with lung disease and in scuba diving. In the case of patients in the hospital, they are receiving very high concentrations of oxygen for more than 12 hours via a closed system (endotracheal tube), and lung injury results from a combination of free radical oxygen formation and dry air. In the case of scuba diving, the partial pressure of oxygen increases as a diver descends deeper and this increases oxygen in the blood. When the oxygen concentration surpasses 160% of normal, seizures can occur.
But these are not the type of scenarios you'd experience when using supplemental oxygen therapy or a hyperbaric oxygen chamber.
Altitude Training & Hypoxia
Exposure to hypoxia does several things in the body. For example, increasing red blood cell mass to increase oxygen transport capabilities is the one you probably already know about. However, there are many other hypoxic and altitude training adaptations that take place, such as structural and functional changes to hemoglobin. A protein called Hypoxia Inducible Factor 1 (HIF-1) is increased with exposure to hypoxia (8). HIF-1 actually tells the kidneys and liver to make erythropoietin (EPO), which in turn tells the bone marrow to produce more red blood cells (interestingly, this same adaptation takes place with sauna training). There are also several genetic adaptations that take place, including higher mRNA levels to hemoglobin. Many enzymes involved in mitochondrial energy processes are both up and down regulated. With prolonged exposure to hypoxia, your white blood cells may decrease, affecting your immune system (8).
Altitude training or simulation of altitude training is accomplished, as you'd probably guess, by living in less oxygen, giving less oxygen, or somehow inducing hypoxia (low oxygen availability). Hypoxic training, or the practice of limiting oxygen availability while training, has been used for decades to improve performance. The United States Olympic Training Center and many other training facilities use hypoxic training to significantly increase the speed of gains in performance (6, 7). A period of altitude training can be helpful to athletes, but it can be a real art to know how long to stay at altitude or a hypoxic environment and when to get out. When using altitude to increase performance, I usually advise athletes to set their altitude tents or altitude training devices at between 12% and 18% oxygen, which corresponds to about 6,000 to 14,000 feet. Most of my athletes will train at altitude or use altitude simulated training blocks for 2-8 weeks at a time.
However, it is very important to monitor your fatigue and ideally other variables such as adrenal stress index and heart rate variability. This is because if you “over-do” altitude, you risk peaking well after the event or even worse, you wind up so fatigued that you can't even function properly.
How could altitude or too much oxygen deprivation cause these issues?
Hypoxia is defined as any condition in which a human breathes less than 21% oxygen, and over a prolonged period of time, this reduced oxygen content of air or a body of water can be detrimental to aerobic respiration. Severe hypoxia can be a devastating complication during a surgery or a heart attack, causing brain injury or death. Fortunately, this type of injury from hypoxia is rare.
Altitude sickness also results from hypoxia and is manageable with proper treatment and prevention. But severe altitude sickness can lead to more serious issues, such as swelling in your lungs and brain and pulmonary hypertension. The take home message is that if you feel sick or weak or fatigued and are not generating an adaptive response to a hypoxic environment, then you need to get back to a lower altitude.
How To Use Hyperoxygenation & Hypoxia
OK, now we get to the fun stuff: the practical applications of using an oxygen concentrator and a hypoxic generator while training.
First, let's clear up what these things really are.
An oxygen concentrator is a machine that pressurizes room air and separates the nitrogen from the oxygen, delivering a high concentration of oxygen and exhausting a high concentration of nitrogen. A hypoxic generator machine works identically the same as an oxygen concentrator, except that the machine has been professionally modified so that the exhaust (the high nitrogen gas), is directed to the person via a tube. Hypoxic generators and oxygen concentrators can be expensive, costing as high as thousands of dollars.
I coach my athletes to train with oxygen concentrators (also known as Exercise with Oxygen, or EWOT) and also hypoxic generators. Sometimes I advise hyperoxia and sometimes hypoxia, depending on the goals. Using a nasal cannula or mask delivery system, athletes can perform exercise intervals in the presence of high oxygen or low oxygen. Usually, these type of intervals are done on an indoor trainer or treadmill.
Exercise with oxygen therapy can increase exercise capacity and lead to performance gains, and this effect is most pronounced at high altitudes (5, 6, personal data). On the flip side, an athlete can use a hypoxic generator to simulate a certain altitude and prepare for elevation competition. As you learned earlier, training in a hypoxic environment boosts the production of red blood cells and causes the other adaptations discussed above.
I also utilize portable oxygen delivery systems. For example, athletes competing in high altitude events can use a special oxygen concentrator that is small enough to fit into a backpack. This means that after the stage or event, they can achieve better recovery, especially if the competition is occuring at high altitude. While training at high altitude and not in a controlled environment such as on a treadmill or indoor bicycle, runners and cyclists can use oxygen via a very small oxygen canisters that fit into a backpack. Athletes who stress about training indoors love this option.
You would use a face mask or a nasal cannula to deliver this oxygen. Some scientists theorize that this could be harmful, but it's important to remember that it's nearly impossible to cause oxygen toxicity or severe hypoxemia, especially when training close to sea level. The reason for this is that oxygen delivery via a mask or nasal cannula always involves some entrainment of room air. When receiving 100 percent oxygen via a nasal cannula, the highest concentration of oxygen that can be delivered is 40%. Using a mask without a re-breather bag, the highest concentration of oxygen that can be delivered is 60%, and with a mask rebreather bag system, the highest concentration of oxygen that can be delivered is 80%.
So delivery of oxygen from an oxygen concentrator is never going to be 100%. Once you throw in the imperfections of a mask, it's readily apparent that no one is going to get hurt by breathing pure oxygen while training. Sure, drying of the airway might be a concern if you are using oxygen for hours at a time, and this is particularly only a problem if training in a dry environment like Las Vegas, Nevada or Boulder, Colorado.
Then there's Hyperbaric Oxygen Therapy (HBOT). HBOT use is increasing each year by medical professionals, sports practitioners, and health spas. Anyone can purchase a HBOT machine for home use. HBOT was first developed for deep sea divers suffering from decompression illness (the bends), and off-lable, HBOT is now being used to treat autism, multiple sclerosis, stroke and brain injury. The dangers of HBOT are rare but real, and include seizures, collapsed lung and combustion.
The main effect of HBOT is hyperoxia (high oxygen availability). The physiological effects of HBOT include enhanced oxygen delivery, reduction of edema, increased immune system and decreased inflammation. New blood vessel formation, bone growth, as well as collagen production are also known long term effects (9). This can be especially beneficial for wound healing and recovery from radiation injury, and may allow for faster recovery from hard, damaging workouts. Paradoxically, HBOT causes vasoconstriction (shrinking of blood vessels), but the resulting elevated carrying capacity of oxygen in the arterial blood results in augmented oxygen delivery to tissues (9).
HBOT seems to be promising in the recovery of injuries or recovery from hard workouts, but larger randomized controlled studies are needed to confirm that it is a safe and effective therapy for these type of situations. One of the downsides is that since you must be lying down or standing up in a small chamber, exercise cannot be easily combined with HBOT. But at the end of the day, HBOT does indeed increase the oxygen delivery to the tissues and blood, and multitudes of athletes swear by it (even athletes who are not sponsored by any HBOT companies).
Product List – Tricks Of The Trade
OK, so what do you need to get started with either hyperoxia or hypoxia training? Here's a list of my favorite tricks of the trade.
Altitude Training Tent or Altitude Chamber
I would recommend you purchase a tent from a company like Hypoxico, who can also outfit any room in your house to be an altitude chamber. However, I do have athletes who construct their own tents using PVC pipe and a thick grade plastic and tape. In this video, Jonathan Hornbeck, currently a professional cyclist for Team Hincapie demonstrates how to make your own tent.
Oxygen Saturation Monitor
Although any oxygen saturation monitor would work for seeing a rise or drop in your blood oxygenation levels, I really like the Masimo Mighty Sat, which is the highest tech oxygen saturation monitor that I have found, and is available to the public. Dotsie Bausch, a silver medalist in the 2012 Olympics, uses Masimo products. The main difference is that the Masimo pulse oximeter is always accurate, and it measures the Plethysmosography Variablility Index (PVI) which measure the changes in your blood perfusion during the respiratory cycle. Simply, PVI is another tool to measure fluid status after large shifts in blood volume, such as would occur with heavy exercise. Finally, a pulse oximeter is another verification that I am indeed training in a hypoxic state while performing hypoxic intervals or resting in a tent. Just about any pulse oximeter will get the job done.
I use an oxygen analzyer to monitor the oxygen concentration in my altitude tent or exercise circuit – I use the Pro O2 Oxygen analyzer from Nuvair. It's dependable and they provide a good warranty. Nuvair specializes in scuba equipment, and for the money, it does the job and rivals more expensive versions. In fact, one of my riders, Romain Bardet, who rides for the Ag2r pro cycling team, uses this exact model for his altitude tent.
You can buy an oxygen concentrator new online, but I suggest looking up an oxygen concentrator repair shop in your area and inquire about buying a new or refurbished oxygen concentrator. Get one that puts out at least 5 liters per minute. Andy Champagne from O2CRS, a local shop in Las Vegas, is very knowledgeable and reasonably priced. I use an oxygen concentrator mainly for my high intensity intervals. But I also use it when the air quality gets really bad or I have inhaled a bunch of smoke. Firefighters use oxygen concentrators regularly to detox the levels of carbon monoxide in their bodies after fighting a fire.
Companies like Hypoxico make a great machine for altitude training that you can roll around in your basement, garage, or gym. Alternatively, you can have a professional modify an existing oxygen concentrator machine into a hypoxic generator. Again, the guys at O2CRS.com do a great job.
Companies like LiveO2 make a portable, easy to use oxygen reservoir that works really well for exercising with supplemental oxygen. Alternatively, it is possible to make one yourself by using a small trash can, then sealing the top and creating an inlet and outlet. Here is a video of the LiveO2 oxygen reservoir system.
Altitude Training Masks
A double one-way valve mask is required for oxygen or hypoxia exercise circuits. Hypoxico sells a mask that is specially made for hypoxic interval training. Sometimes you will find these masks on Amazon and Alibaba commerce websites. Please note that an elevation training mask is not the same thing, and Ben explains why here.
Pure oxygen requires a prescription from a doctor. However, welding grade oxygen is still 94% pure, and still does the job. In fact, oxygen bars use welding grade oxygen. So align yourself with a welding shop or oxygen company and have them fill your oxygen tanks for you and you should be good!
Some of my athletes who train at very high altitudes will actually use an oxygen tank along with a nasal cannula, both of which are small enough to fit into a backpack. Just before they are about to start their intervals, they will turn the oxygen dial to hi-flow and perform their intervals. This allows them to increase their exercise capacity at higher altitudes.
Let's finish with an example of a supplement oxygen interval training session that I personally perform using an oxygen concentrator and a universal mask circuit. It's quite simple and consists of one minute long all-out intervals. First, I warm up, and then exercise at an easy, aerobic pace for 5 minutes, followed by 1 minute all-out, followed by a 4 minute recovery, then 1 minute all-out, and so on until I get to 1 minute all-out and 1 minute rest, at which time I repeat the intervals 1 to 3 times.
So to clarify – you would do the following wearing a mask and nasal cannula that is connected to supplemental oxygen :
5 easy, 1 hard.
4 easy, 1 hard.
3 easy, 1 hard.
2 easy, 1 hard.
1 easy, 1 hard.
Ben has been experimenting with a Hypoxico Everest II altitude simulator for hypoxia, using an Intermittent Hypoxic Training (IHT) protocol very similar to that outlined in these instructions (5 minutes exercise with hypoxia, followed by 5 minutes without hypoxia, for 30-60 minutes at an aerobic pace).
It appears that when it comes to hypoxic training, you can also benefit from short, repeated 10-30 second high-intensity bursts followed by longer recovery periods, a strategy which appears to be just as beneficial as longer efforts and is outlined in detail in this study, and also in this section of the Wikipedia page on altitude training.
So that's it! Do you have questions, comments or feedback for Ben or Dr. Edwards, your own oxygen biohacks to add, or anything else you'd like to share? Leave your thoughts below and either Dr. Edwards or I will reply.
- Med Sci Sports Exerc. 2005 Jul;37(7):1175-9.
Effects of hyperoxic training on performance and cardiorespiratory response to exercise.
- J Sports Sci. 2012 May;30(9):851-8.
Effects of hyperoxia during recovery from 5×30-s bouts of maximal-intensity exercise.
- J Exp Biol. 2001 Sep;204(Pt 18):3225-34.
Evidence that a central governor regulates exercise performance during acute hypoxia and hyperoxia.
- The Effect Of Training While Breathing Oxygen-Enriched Air On Time-To-Exhauston And Aerobic Capacity
- Med Sci Sports Exerc. 2004 Nov;36(11):1888-94.
Effect of FIO2 on oxidative stress during interval training at moderate altitude.
- Altitude, hypoxic and hyperoxic Training: research evidence vs. practical applications
- J Exp Biol. 2001 Sep;204(Pt 18):3195-9.
Human aerobic performance: too much ado about limits to V(O(2)).
- J Exp Biol. 2001 Sep;204(Pt 18):3133-9.
Muscle tissue adaptations to hypoxia.
- Hyperbaric effects on sports injuries PDF
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