Altitude Training Relevance and Limits

SPORTS SCIENCE IMPROVING ENDURANCE PERFORMANCE WITH ‘LIVE HIGH - TRAIN LOW’ ALTITUDE TRAINING RELEVANCE AND LIMITS – Written by Paul Robach, France and Carsten Lundby, Switzerland Historically, altitude training has been aerobic performance in humans. This failure sport federations to build a substantial defined as the practice adopted by athletes prompted athletes and coaches to implement number of hypoxic facilities worldwide. who train for several weeks in an oxygen- altitude training camps with the objective After several decades and the involvement deprived environment (altitude training to acclimatise to competition at altitude. It of a large number of elite athletes who camp) in order to improve their endurance soon became apparent, however, that alti- sometimes set new world records after performance. By extension, altitude training tude training also could improve endurance returning from altitude, the key question refers to the use of natural or simulated performance upon return to sea level. The arises: does it really work? Unfortunately, altitude conditions during the course of rationale was that on the one hand, total red to date the majority of well-controlled the training process, at rest and/or during blood cell volume is a key factor for endurance scientific studies fail to demonstrate a exercise. Whatever the altitude training performance, as highlighted by experiments systematic positive effect of altitude training strategy, athletes exposed to altitude are incorporating blood manipulations. The on endurance performance in athletes. facing low-oxygen pressure (hypoxia), larger number of red blood cells an athlete Nonetheless, a common observation resulting in a lower blood and tissue has, the faster he will probably be able to is that some athletes do benefit from this oxygenation (hypoxemia). run a marathon. On the other hand, altitude method, while others do not (reports of a Altitude training became popular at the exposure triggers the secretion of the renal reduction in exercise capacity also exist). time of the 1968 Olympic Games in Mexico hormone erythropoietin (EPO), which in So, the next question is: why does altitude (located at 2,400 m), where endurance turn stimulates red blood cell synthesis i.e. training fail to induce a consistent positive athletes not only failed to set new records provided that the ‘altitude dose’ is sufficient. effect on performance? (as opposed to sprinters) but also decreased So, the original concept was that combining Firstly, scientific literature indicates that their performance (e.g. 3000 m steeplechase, training and altitude would boost total red the individual variation in the adaptive 10,000 m and marathon disciplines). The blood cell volume and therefore endurance responses to altitude is very large in humans, main reason for this was obviously altitude performance. The fact is that over the years, and the determinants of altitude tolerance hypoxia, a condition known to decrease this attractive hypothesis has led numerous exposure are poorly understood. 10 capacity) are thought to enhance exercise performance after ‘live low-train high’. The present article focuses on performance improvements and haematologic adaptations induced by the ‘live high - train low’ altitude training intervention. ‘LIVE HIGH - TRAIN LOW’ ALTITUDE TRAINING Often considered as a variation of classic altitude training, the principle of ‘live high - train low’ is the following: living/sleeping at altitude for several weeks enables total red blood cell volume to increase (similarly to classic altitude training), while training at or near sea level allows the athletes to maintain their training intensities within normal levels (contrary to classic altitude training, where absolute training intensities are generally reduced). By doing so, training- related problems are overcome and one may therefore expect more consistent adaptations than with classical altitude training. The approach was allegedly first tested on an empirical basis by some athletes in the Italian Alps in the 1980s, but was first shown to be beneficial for enhancing aerobic performance by American scientists in the late 1990s1. Since then, several other studies have confirmed that ‘live high - train low’ might confer some physiological advantages, such as an increase in total Secondly, at a practical level, exercising natural altitude for several weeks) remains red blood cell volume and ultimately, an in hypoxia poses a major problem, which a popular method. improvement in maximal oxygen transport. is the management of training intensities. Of note, there is no definitive consensus Because maximal exercise capacity is NEW METHODS about the mechanism(s) underlying the reduced under hypoxic conditions, training The various problems encountered with increase in performance. Some authors at altitude at the same absolute intensity classical altitude training have prompted suggest, on a rather robust evidence base, as at sea level represents a larger stimulus scientists and coaches to investigate that haematological adaptation is the that could eventually lead to overtraining. alternative methods, whereby the athletes main factor. Others have rather proposed Conversely, conserving the same relative are discontinuously exposed to hypoxia at that skeletal muscle function (but not red intensity at sea level (i.e. decreasing running rest and/or during exercise sessions. The blood cell number) is improved after ‘live speed) has the potential to alter running first of these methods is ‘live high - train high - train low’, so that muscle efficiency skills or even induce detraining. Therefore, low’ and consists of sleeping at altitude and therefore endurance performance are in such a challenging environment, it is to gain the haematologic adaptations maximised2. very difficult for the coaches to design the (increased erythrocyte volume) but training Beyond the concept’s attractiveness or optimal training regimen adapted to each near sea level to maximise performance any scientific evidence, it is important to athlete. As a consequence, the likelihood (preservation of sea level training intensity acknowledge that simplicity is certainly of obtaining the expected positive effect and oxygen flux). Another method is the another reason behind the success of this on performance for all athletes is low. That ‘live low - train high’ method including approach. Breathing hypoxic air during said, numerous anecdotal reports showing intermittent hypoxic exposure during sleep is easy to implement everywhere on that elite endurance athletes have produced training sessions. However, given the Earth and is by far much less expensive or word-class records after a prolonged sojourn relatively short duration of hypoxic complicated than organising a long training at altitude certainly explain why classical exposure, muscular adaptations (and not camp in the mountains, even if the use altitude training (i.e. living and training at necessarily an improved oxygen carrying of natural altitude (hypobaric hypoxia) 11 SPORTS SCIENCE 11 10 R = 0.86 P < 0.01 9 8 Brugniaux et al 2006 Figure 1: Significant in- verse relationship exist- 7 Clark et al 2009 ing between the initial mass level of total haemoglobin 6 Garvican et al 2011 mass (Hb , body-weight Levine & Stray-Gundersen 1997 mass 5 adjusted) measured prior Robach et al 2006 to ‘live high - train low’ 4 altitude training and the Increase in Hb Robertson et al 2010 relative increase in Hb 3 mass induced by ‘live high - train after ‘Live high - train low’ (%) Saunders et al 2010 2 low’. The relationship is Siebenmann et al 2011 based on nine previously 1 published studies on ‘live Wehrlin et al 2006 high - train low’6. 0 9 10 11 12 13 14 15 -1 Initial Hbmass (g.kg %) was proved efficient1. Indeed, building challenged by a study conducted on highly- highly dependent on technical and tactical hypoxic rooms or even sleeping in hypoxic trained cyclists, for the first time in a double skills usually possess a total haemoglobin tents is technologically affordable, since blind manner, showing no change in mass of 11 g.kg-1 within or slightly above atmospheric pressure is not modified; only endurance performance5. In these athletes, the normal range (10 to 11 g.kg-1). For those the fraction of oxygen has to be reduced neither total red blood cell volume nor athletes it is reasonable to expect that ‘live (with oxygen extraction or nitrogen skeletal muscle function improved after high - train low’ may substantially increase enriching) in order to simulate altitude. ‘live high - train low’ intervention. Such their red blood cell synthesis, therefore After 20 years of research on ‘live high findings clearly raise the question of the reinforcing their aerobic potential. Whether - train low’, the general consensus is that actual ergogenic effects of ‘live high - train this translates into an elevated exercise this method may help some, but not all, low’ in elite endurance athlete populations performance is questionable, as one would athletes in improving their performance. i.e. those already possessing very high assume the organisms of elite athletes In this context, natural altitude seems to be levels of total red blood cell volume and already to be fully optimised, i.e. if a high more efficient than artificial hypoxia, while maximal oxygen uptake, therefore having haemoglobin mass and aerobic capacity sub-elite athletes might benefit more from very little room for further improvement. would be a requirement in order to

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