Noakes, T. D. (2000). Physiological models to understand exercise fatigue and the adaptations that predict or enhance athletic performance. Scandinavian Journal of Medicine and Science in Sports, 10, 123-145.

The presence of a "governor" preventing the development of anaerobiosis in either heart or skeletal muscle during exercise at altitude has interesting implications for theories of the value of exercise training at altitude. For its presence means that any beneficial effect of altitude training cannot result from repeated exposure of either the heart or exercising muscle to greater levels of [fictional] "anaerobiosis" than can be achieved during maximal exercise at sea level. This might explain why there remains considerable controversy about the proven value of high intensity training at altitude. (p. 129).

Adaptation at altitude is accompanied by the following phenomena that are paradoxical to improving performance capabilities.

• A reduced skeletal muscle mitochondrial volume and enzyme content.
• Skeletal muscle morphology of altitude residents (e.g., Nepalese Sherpas) is no different from that of acclimatized Caucasians.
• The volume density of skeletal muscle mitochondria is significantly smaller in altitude residents than in sea level untrained subjects. [Exercise performance at altitude is better explained as being determined by factors producing superior oxygenation of the heart, rather than skeletal muscles.]

Implication. There is no physiological model that supports the contention that altitude training improves performance.

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