Last week at the World Congress on Mountain and Wilderness Medicine in Aviemore Scotland, world experts convened to discuss a wide variety of interesting subjects. One such session explored the controversy and current science of athletic training involving sleeping in hypoxic altitude tents. Does it work? Is it sporting/fair? Dr Ben Levine included the following points in his discussion of the topic, his syllabus reproduced here from the website (http://www.worldcongress2007.org.uk):
Altitude training continues to be a key adjunctive aid for the training of competitive athletes throughout the world. Over the past decade, evidence has accumulated from many groups of investigators that the "living high – training low" approach to altitude training provides the most robust and reliable performance enhancements. The success of this strategy depends on two key features: 1) living high enough, for enough hours per day, for a long enough period of time, to initiate and sustain an erythropoietic effect of high altitude; and 2) training low enough to allow maximal quality of high intensity workouts, requiring high 
rates of sustained oxidative flux. Because of the relatively limited access to environments where such a strategy can be practically applied, numerous devices have been developed to "bring the mountain to the athlete," which has raised the key issue of the appropriate "dose" of altitude required to stimulate an acclimatization response and performance enhancement. These include devices using molecular sieve technology to provide a normobaric hypoxic living or sleeping environment, approaches using very high altitudes (5,500m) for shorter periods of time during the day, and "intermittent hypoxic training" involving breathing very hypoxic gas mixtures for alternating 5 minutes periods over the course of 60-90 minutes.
Unfortunately, objective testing of the strategies employing short term (less than 4 hours) normobaric or hypobaric hypoxia has failed to demonstrate an advantage of these techniques. Moreover individual variability of the response to even the best of living high – training low strategies has been great, and the mechanisms behind this variability remain obscure. Future research efforts will need to focus on defining the optimal dosing strategy for these devices, and determining the underlying mechanisms of the individual variability so as to enable the individualized "prescription" of altitude exposure to optimize the performance of each athlete.
The recent doping scandals surrounding the Tour de France serve as a stark reminder that despite current anti-doping efforts, cheating remains quite prevalent in sport. Indeed, it was following a major scandal at the Tour de France of 1998 that the modern World Anti-Doping Agency (WADA) was born. At present, in order for a substance or method to be considered for placement on WADA's Prohibited List, it must meet two of three criteria: 1). Scientific evidence or experience demonstrates that the method or substance has the potential to enhance, or enhances sport performance; 2). Medical evidence or experience suggests the that the use of the substance or method represents an actual or potential health risk to the athlete; 3). The use of the substance or method violates the spirit of sport.
One method that has recently attracted the attention of WADA is the use of "artificial" hypoxic or high altitude environments to simulate high altitude training. Athletes sleeping in a hypoxic tent, with the intent at least in part to increase endogenous production of erythropoietin, present an image that makes some in the sporting
community uncomfortable. Therefore last summer WADA turned its attention to these devices to determine if they meet the criteria for placing this method on the Prohibited List for 2007. In doing so, they convened a panel to help clarify the meaning of the "spirit of sport" which argued that the "passive" use of the high altitude simulation that constitutes the most egregious violation of the spirit of sport. In response to the ethics committee recommendations and WADA's consideration of artificial altitude environments as a method to be placed on the Prohibited List for 2007, a group of 76 physicians, bioethicists, and sports scientists from 24 countries experienced in the field of human performance and hypoxia, developed a comprehensive set of arguments which were presented to the WADA Executive Committee. This letter included the following key points:
- The benefits of artificially induced hypoxic conditions for sport performance have not been firmly established in the scientific literature, and in fact are controversial. This uncertainty, due in part to the individual variability of each athlete's genetic endowment and insightful application of this technology, is in distinct contrast to the clear understanding that exists regarding the mechanisms and physiological outcome of EPO and blood doping.
- The effects of artificial hypoxic environments used for training are safe, in contrast to blood doping and many performance enhancing drugs.
- The argument that artificial hypoxic environments are "passive" and that this passivity distinguishes acclimatization to hypoxia from other environmental exposures or aids to recovery is logically inconsistent and scientifically untenable. As only one example, tolerance to heat stress acquired by sitting in a sauna can produce more profound and consistent physiological benefits than acclimatization to simulated high altitude.