NORMOBARIC HYPOXIA INDUCES ANAEROBIC CHANGES MORE THAN AEROBIC CHANGES
Meeuwsen, T., Hendrickson, I. J., & Holewijn, M. (2000). Training-induced increases in sea-level performance is enhanced by acute intermittent hypobaric hypoxia: A 2-year cross-over study. Medicine and Science in Sports and Exercise, 32(5), Supplement abstract 1222.
This study assessed to what extent intermittent exposure to altitude in a hypobaric chamber can induce physiological changes and improve performance at sea level. Elite male triathletes (N = 16) altered there training for a 10-day period during each of two years. Usual training was replaced by everyday training sessions on a cycle ergometer in a hypobaric chamber. Training lasted two hours each day at an intensity of 60-70% of heart rate reserve. Ss (N = 8) trained at a simulated altitude of 2,500 m, and the other eight Ss trained at sea level. In the second year, the training groups reversed their training experience. Measurements were taken before, during, and after the 10-day exposure. [No control groups were used in this study. Sequencing effects and program content, such as training intensity, were not controlled.]
Hypoxia did not increase VO2max, but it did improve mean maximal power output. Mean anaerobic power and capacity increased significantly, while hematocrit and hemoglobin levels did not change. At sea level, hematocrit increased significantly, but no other factors changed.
Intermittent normobaric hypoxia improved the anaerobic energy supply system. If Ss were already well adapted aerobically, but had lots of room for improvement in anaerobic capacity, the anaerobic development is easily understood.
Implication. Normobaric hypoxia stimulates anaerobic changes more than aerobic changes.
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