TRAINING, NOT HYPOXIC EXPOSURE, INFLUENCES PERFORMANCE
Austin, K. G., Haymes, E., Hansen, J., & Laird, M. (2006). The effect of intermittent hypoxic exposure on hematological markers and exercise performance. Medicine and Science in Sports and Exercise, 38(5), Supplement abstract 903.
This study examined the erythropoietic response to intermittent hypoxic exposure vs. intermittent hypoxic training, and to assess the effects of each on endurance performance. Ss (N = 9) completed two experimental normobaric hypoxic trials of the two conditions and a control period of 28 days. Normobaric hypoxic trials were completed at 14.4% O2 concentration (~3000m simulation) for two hours per day and consisted of: 1) a resting passive exposure, and 2) cycling exercise at ~60-70% of heart rate reserve. Assessments of erythropoietin, free testosterone, hemoglobin, hematocrit, reticulocytes, serum iron, transferring saturation, transferrin recptor, and ferritin were taken on days 0, 1, 5, 14, 28 and one day after each trial. Evaluations of VO2max, lactate threshold, submaximal exercise capacity, and time trial were conducted before and after each trial.
Measures of erythropoietin, hemoglobin, hematocrit, reticulocytes, serum iron, transferrin recptor, and ferritin did not demonstrate any significant trial by time interactions. Using performance measures as the dependent variable, there were no differences for VO2max, lactate threshold, and submaximal exercise capacity. Time trial performance was significantly faster following intermittent hypoxic training when compared to pre-exposure times, although post-experiment time trials both conditions were not significantly different.
Implication. Intermittent hypoxic training provides greater, but not significantly different to intermittent hypoxic exposure, gains in time trial performance. Intermittent hypoxic exposure does not alter factors related to enhancement of performance.
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