Laymon, A. S., Wilhite, D. P., Duke, J. W., Stickford, J. L., Stager, J. M., Mickleborough, T. D., & Chapman, R. F. (2012). Time-course of changes in cardiorespiratory measures post-altitude training: Implications for competitive endurance performance. Presentation 2158 at the 59th Annual Meeting of the American College of Sports Medicine, San Francisco, California; May 29-June 2, 2012.

This study described serial changes in cardiorespiratory measures related to performance in elite distance runners over three weeks at sea-level immediately following return from a “live high - train low” altitude camp. Elite male distance runners (N = 6) completed a 28-day altitude training intervention at 2,150 m, following a live high - train low training model. Isocapnic hypoxic ventilatory response, submaximal and maximal exercise ventilation, oxygen uptake, heart rate, and respiratory muscle VO2 were measured in the one week prior to and within 24 hours upon return (Day 1) from altitude. Additional sea-level measures of the isocapnic hypoxic ventilatory response and submaximal exercise ventilation, oxygen uptake, heart rate, and respiratory muscle VO2 were taken on Days 5-6, 12-13, and 20-21 post-altitude. Competitive performance was assessed via race times at sea-level over 26 days post-altitude. The isocapnic hypoxic ventilatory response was significantly elevated above pre-altitude levels on Day 1 post-altitude and declined back to pre-altitude levels over the ensuing three weeks. There were no significant differences between any cardiorespiratory measures during maximal exercise pre- to Day 1 post-altitude. During submaximal exercise, oxygen uptake tended to be lower at all speeds and on all days post-altitude when compared to pre-altitude. Heart rate was significantly lower on Days 1, 5, and 20 at all speeds compared to pre-altitude, but not at Day 12 Following a similar pattern, the respiratory muscle VO2 was less than pre-altitude measures on Day 1 post-altitude and rose to a peak at Day 12 before declining again at Day 20. Average race time in competition on Days 9-10 post-altitude was 0.4% slower than the athlete’s pre-altitude personal best; results from competition on Day 26 showed an average time of 0.6% faster than pre-altitude best.

Implication. The time course of changes in cardiorespiratory measures post-altitude training appears to follow a pattern that matches the anecdotally noted timing of best competitive performances. Competitive performances at sea-level after nine days were slower but improved at Day 26. It is not possible to determine if the eventual improvement on Day 26 was due to altitude-adaptation effects or the effects of further training at sea-level.

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