Live high train low?
Oct 16, 2007 15: 31 EST
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/) Read on:
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:
1). 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.
2). The effects of artificial hypoxic environments used for training are safe, in
contrast to blood doping and many performance enhancing drugs.
3). 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.
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