Short-term arrival strategies for endurance exercise performance at moderate altitude
For sea level-based endurance athletes who compete at moderate and high altitudes, many are not logistically able to arrive at altitude weeks prior to the event to fully acclimatize. For those who can only arrive at altitude the night before competition, we asked if there is a physiological and performance advantage in reducing altitude exposure time to two hours prior to competition. On three separate visits, ten cyclists completed overnight laboratory exposures of: 1) a 14-hour exposure to normobaric hypoxia (16.2% O2, simulating 2500m; 14H), 2) a 12-hour exposure to normoxia, then a 2-hour hypoxic exposure (2H), and 3) a 14-hour exposure to normoxia (CON). Immediately following each exposure, subjects completed a 20-km cycle ergometry time trial in normoxia (CON) or 16.2% O2 (14H and 2H). Measures of plasma volume changes, sleep quality, ventilatory acclimatization, perceived exertion, oxygen uptake, and 20-km time were collected. No significant differences were observed in performance measures or perceived exertion between hypoxic trials. Plasma volume loss was significantly greater during 14H than 2H and CON. No differences in ventilatory acclimatization or sleep quality were observed between trials. Although some divergent 20-km performance responses were observed between 14H and 2H, they were not explained by the physiological measures completed. The data suggest that endurance athletes who are logistically restricted from arriving at altitude more than the evening prior to competition would not gain an advantage by delaying their arrival until a few hours before the competition, although unique individual responses may ultimately influence optimal arrival strategy.
Autor / Fonte:Joshua L Foss, Keren Constantini, Timothy D Mickleborough, Robert F Chapman Journal of Applied Physiology 2017 August 17, : jap.00314.2017