INCREASED VENTILATORY WORK INCREASES OXYGEN UPTAKE AFTER ALTITUDE ACCLIMATIZATION
Lundgren, E. A., Wilhite, D. P., Laymon, A. S., McKenzie, J. M., & Chapman, R. F. (2009). Running economy changes after altitude training: Role of ventilatory acclimatization. ACSM 56th Annual Meeting, Seattle, Washington. Presentation number 2359.
This study determined if potential running economy changes after altitude training can be explained by changes in ventilatory factors. Elite male distance runners (N = 6) completed a 28-day altitude training intervention in Flagstaff, Arizona (elevation 2,150 m) following a "live high - train low" training model. Running economy and expired ventilation were measured 2-9 days prior to departure to altitude and 1-2 days after return to sea level. Running economy was determined from VO2 measured in the final minute of 3-minute stages at three constant submaximal treadmill speeds of 291, 301, and 311 m/min. Respiratory muscle VO2 was estimated.
Post-altitude VO2 and expired ventilation were higher at each submaximal workload. Estimated respiratory muscle VO2 accounted for 12.3%, 11.0%, and 14.2% of the increase in whole body VO2 at each of the three submaximal workloads after altitude training. Submaximal VO2 increased after chronic altitude training. Although ventilation increased post-altitude, the estimated metabolic cost of ventilation explained 11.0 - 14.2% of the VO2 increase. The source of the remaining submaximal VO2 change after altitude training remains unknown.
Implication. A large proportion of increased oxygen uptake after altitude acclimatization demonstrated in submaximal running tasks is due to the increased work of ventilation.
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