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.

"Coaches have anecdotally noted that best performances following altitude training occur either: a) very early after return from an altitude training camp, or b) after a period of 10-25 days of post-altitude sea-level training. However, there is little scientific evidence to support these “ideal” times for post-altitude competition."

This study described serial changes in cardiorespiratory measures related to performance in elite distance runners (males; N = 6) over three weeks at sea-level, immediately following return from a 28-day “live high - train low” (LHTL; 2,150 m) altitude camp. Isocapnic hypoxic ventilatory response (HVR), 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 (D1) from altitude. Additional sea-level measures were taken on days 5-6 (D5), 12-13 (D12), and 20-21 (D20) post-altitude. Competitive performance was assessed via race times at sea-level 26 days post-altitude.

Isocapnic hypoxic ventilatory response was significantly elevated above pre-altitude levels at D1 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-altitude to D1. During submaximal exercise, VO2 tended to be lower at all speeds on all days post-altitude when compared to pre-altitude values. Heart rate was significantly lower at D1, D5, and D20 at all speeds compared to pre-altitude, but not at D12. Following a similar pattern, the respiratory muscle VO2 was less than pre-altitude measures at D1 and rose to a peak at D12 before declining again at D20. 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 a competition on day 26 showed an average time of 0.6% faster than pre-altitude best time.

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. Whether post-altitude variations in competitive performance are explained by physiological de-acclimatization effects or post-altitude training effects has yet to be determined.

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