Intermittent Hypoxic Training: Fact and Fancy

Abstract

LTITUD E TRAINING has been used frequently by endurance athletes to enhance performance. However, not all athletes or teams have the resources to travel to high altitude environments on a regular basis. Moreover, issues such as availability of adequate training facilities have limited the use of mountain-based altitude training. In the last few years, there has been a remarkable increase in the number of techniques designed to "bring the mountain to the athlete." Nitrogen houses, hypoxia tents, and special breathing apparatuses to provide inspired hypoxia at rest and during exercise, all have been developed and promoted to simulate what are perceived as the critical elements of altitude training.Intermittent hypoxic training (IHT) refers to the discontinuous use of normobaric or hypobaric hypoxia, in an attempt to reproduce some of these key features of altitude acclimatization, with the ultimate goal to improve sea-level athletic performance. In general, IHT can be divided into two different strategies: (1) providing hypoxia at rest with High Alt Med Biol. 3:177-193, 2002.-Intermittent hypoxic training (IHT) refers to the discontinuous use of normobaric or hypobaric hypoxia, in an attempt to reproduce some of the key features of altitude acclimatization, with the ultimate goal to improve sea-level athletic performance. In general, IHT can be divided into two different strategies: (1) providing hypoxia at rest with the primary goal being to stimulate altitude acclimatization or (2) providing hypoxia during exercise, with the primary goal being to enhance the training stimulus. Each approach has many different possible application strategies, with the essential variable among them being the "dose" of hypoxia necessary to achieve the desired effect. One approach, called living high-training low, has been shown to improve sea-level endurance performance. This strategy combines altitude acclimatization (2500 m) with low altitude training to ensure high-quality training. The opposite strategy, living low-training high, has also been proposed by some investigators. The primacy of the altitude acclimatization effect in IHT is demonstrated by the following facts: (1) living high-training low clearly improves performance in athletes of all abilities, (2) the mechanism of this improvement is primarily an increase in erythropoietin, leading to increased red cell mass, V O 2max , and running performance, and (3) rather than intensifying the training stimulus, training at altitude or under hypoxia leads to the opposite effect-reduced speeds, reduced power output, reduced oxygen flux-and therefore is not likely to provide any advantage for a well-trained athlete.

Changes in heart rate recovery index after a programme of strength/endurance training in hypoxia

“…9,10 Interest in this topic was aroused because of the excellent results in endurance events (with predominant aerobic metabolism) achieved by African athletes residing at moderate altitudes. 11 It was the incursion of these athletes at the 1968 Mexico Olympics, and their subsequent overwhelming dominance in these events that spurred studies into finding explanations for these quantitative differences in physical performance.…”

Effects of the ‘live high–train low’ method on prooxidant/antioxidant balance on elite athletes

“…Nevertheless, scientific studies showed conflicting results probably due to the complex adaptation of training load in hypoxia (Levine, 2002). The 'living high-training low' (LHTL) model purposed by Levine et al (1991) reduces the deleterious effects of altitude exposure during training caused by reduced exercise intensity.…”

Acute Normobaric Hypoxia Stimulates Erythropoietin Release

“…Erythropoietin (EPO) is largely produced by the cells of the kidney and is responsible for the regulation of red blood cell production (see review: Wang and Semenza, 1996). The drop in tissue partial pressure of O 2 (P O 2 ), resulting from both environmental hypoxia and altitude, has the ability to encourage EPO release (see reviews : Wilber, 2001;Levine, 2002). Despite the depth of research supporting hypoxic-induced increases in EPO, there is still evidence contradicting such findings (Table 1).…”