Contemporary Periodization of Altitude Training for Elite Endurance Athletes: a Narrative Review
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Sports Medicine https://doi.org/10.1007/s40279-019-01165-y REVIEW ARTICLE Contemporary Periodization of Altitude Training for Elite Endurance Athletes: A Narrative Review Iñigo Mujika1,2 · Avish P. Sharma3,4 · Trent Stellingwerf5,6 © Springer Nature Switzerland AG 2019 Abstract Since the 1960s there has been an escalation in the purposeful utilization of altitude to enhance endurance athletic per- formance. This has been mirrored by a parallel intensifcation in research pursuits to elucidate hypoxia-induced adaptive mechanisms and substantiate optimal altitude protocols (e.g., hypoxic dose, duration, timing, and confounding factors such as training load periodization, health status, individual response, and nutritional considerations). The majority of the research and the feld-based rationale for altitude has focused on hematological outcomes, where hypoxia causes an increased erythropoietic response resulting in augmented hemoglobin mass. Hypoxia-induced non-hematological adaptations, such as mitochondrial gene expression and enhanced muscle bufering capacity may also impact athletic performance, but research in elite endurance athletes is limited. However, despite signifcant scientifc progress in our understanding of hypobaric hypoxia (natural altitude) and normobaric hypoxia (simulated altitude), elite endurance athletes and coaches still tend to be trailblazers at the coal face of cutting-edge altitude application to optimize individual performance, and they already implement novel altitude training interventions and progressive periodization and monitoring approaches. Published and feld-based data strongly suggest that altitude training in elite endurance athletes should follow a long- and short-term periodized approach, integrating exercise training and recovery manipulation, performance peaking, adaptation monitoring, nutritional approaches, and the use of normobaric hypoxia in conjunction with terrestrial altitude. Future research should focus on the long-term efects of accumulated altitude training through repeated exposures, the interactions between altitude and other components of a periodized approach to elite athletic preparation, and the time course of non-hematological hypoxic adaptation and de-adaptation, and the potential diferences in exercise-induced altitude adaptations between diferent modes of exercise. Key Points A long- and short-term periodized approach to alti- tude training seems to be necessary for elite endurance athletes to obtain maximal beneft from the hypoxic * Iñigo Mujika stimulus. [email protected] Detailed longitudinal monitoring of an athlete’s physical 1 Department of Physiology, Faculty of Medicine and perceptual responses to training is required before, and Odontology, University of the Basque Country, Leioa, during, and after an altitude sojourn to maximize the Basque Country, Spain 2 benefts of altitude training and minimize the risk of Exercise Science Laboratory, School of Kinesiology, Faculty maladaptation. of Medicine, Universidad Finis Terrae, Santiago, Chile 3 Grifth Sports Physiology and Performance, School of Allied Other confounding interventions may need strategic Health Sciences, Grifth University, Gold Coast, QLD, periodization in combination with altitude training, such Australia as nutrition, the combined use of terrestrial altitude and 4 Triathlon Australia, Burleigh Heads, QLD, Australia normobaric hypoxia, and/or heat adaptation. 5 Canadian Sport Institute-Pacifc, Victoria, BC, Canada 6 Department of Exercise Science, Physical and Health Education, University of Victoria, Victoria, BC, Canada Vol.:(0123456789) I. Mujika et al. 1 Introduction integrated periodization approach and including coaching aspects of training load and recovery manipulation, ath- Elite endurance athletes have been using low to mod- lete monitoring, and nutritional and other environmental erate altitude (i.e., between ~ 1400 and 2500 m, with stressor considerations. Whenever possible, evidence- 2000–2500 m appearing optimal [1]) training for dec- based recommendations are made, but in some instances ades in an attempt to enhance both their altitude and sea- the authors also draw upon their extensive practical expe- level performance [2–5]. Whether athletes choose to live riences over many years of working with elite endurance high–train high (LHTH) or live high–train low (LHTL), athletes at altitude. Finally, various gaps in the literature the physiological rationale for altitude training is that the are highlighted to stimulate future scientifc exploration. reduced barometric and partial pressure of oxygen results in lowered oxygen availability causing the signaling of hypoxia-inducible factor-1α (HIF-1α), which then causes 2 Planning and Periodization of Altitude an increased erythropoietic response [6] and increased Training in Elite Endurance Athletes hemoglobin mass (Hbmass) [7–9]. However, there are also hypoxia-induced non-hematological changes, such Periodizing training programs for elite endurance athletes to as mitochondrial gene expression and enhanced muscle fulfl maximal performance potential at the right time is a bufering capacity [10]. Combined hematological and non- complex challenge [36]. Long-term career paths are ideally hematological responses can result in increased maximal planned to peak at the end of a quadrennial period culminat- V̇ O oxygen uptake ( 2max ) and/or competition performance ing with the Olympic or Paralympic Games. In the short- at sea level [11], although conficting views still remain, term, peak performances are usually attained by a periodized particularly with regards to LHTL [12, 13]. Several factors approach that skillfully intertwines lengthy phases of inten- impact upon altitude adaptation, such as the duration and sive training and shorter phases of reduced training [29]. It is degree of hypoxic exposure, absolute and relative intensity the authors’ contention that a long- to short-term periodized of training and its distribution, iron availability, injury/ approach that integrates exercise training and other lifestyle, illness status, and inter-individual variability [14–21]. nutritional, and environmental stressors should also apply to Both female and male elite athletes often show progres- altitude training for elite endurance athletes. sive increments in Hbmass at increasing altitudes from 1360 to 2100 and 2320 m [22–24]. Conversely, illness and/or 2.1 Long‑Term Planning of Altitude Training: The injury could inhibit altitude adaptations [22, 25–27] and Value of Repeated Exposures the stress of altitude training may increase the risk of ill- ness [28]. Therefore, poorly planned training programs Multi-year planning of annual altitude exposures over an may sometimes result in deleterious outcomes, such as athlete’s career may be a sound strategy to maximize the underperformance, excessive fatigue, overtraining, illness, benefts of altitude training (Table 1). Indeed, repeated inter- and/or injury [21, 29]. mittent exposures to high-altitudes (3–4 days at 3500 m fol- Thus, it is essential to meticulously plan and periodize lowed by 3–4 days at sea level) in Chilean soldiers over altitude training camps by adequately designing and con- a 22-year period induced Hb mass values 11% higher than trolling training loads, and continuously monitoring an native lowlanders [37]. Moreover, elite Australian swim- individual athlete’s adaptation and health status [30]. For mers showed a linear increase of ~ 10% in Hb mass over a many athletes and coaches, periodization has traditionally 4-year period encompassing eight altitude training camps focused on just the exercise training aspect of an athlete’s [38]. Short-term (3 weeks) relative retention of acclima- preparation, while often neglecting the integration of other tized high-altitude (5260 m) exercise performance occurs elements. Recently Mujika et al. [29] reviewed the sci- in healthy lowlanders upon re-ascent after de-acclimatizing entifc bases underpinning integrated periodization at sea at low altitude [39]. Furthermore, plasma adenosine levels level, featuring multiple periodization facets beyond just are rapidly increased by initial ascent to high altitude, attain- training loads. However, despite many previous reviews ing even higher levels upon re-ascent, a feature that is posi- eloquently describing the physiological adaptations to tively associated with quicker acclimatization [40]. In other hypoxia/altitude [10, 15–17, 31–35], there has not been words, erythrocytes possess a ‘hypoxic memory’ that could a contemporary update on the various periodization and facilitate faster hypoxic acclimatization when participants monitoring aspects of altitude training in elite endurance have previous altitude exposures [40]. In addition, a short- athletes. Therefore, the aim of this article is to review duration sojourn at moderate natural altitude (2220 m) is a the available evidence underpinning the periodization of very efective pre-acclimatization strategy for subsequent altitude training for elite endurance athletes, adopting an higher-altitude exposure (4300 m) in comparison with a direct ascent [41–44]. Although some of these fndings were Periodized Altitude Training for Elite Endurance Athletes Table 1 Long-term planning of altitude training for an Olympic and World Champion female swimmer. Over an 8-year period, this athlete uti- lized altitude training over a total of 120 weeks (34 separate camps, with 18 of the camps 4 weeks in duration; ~ 29% of total training time) Season Weeks