Turner, L. A., Mikkleborough, T. D., Tecklenburg-Lund, S., Stager, J. M., & Chapman, R. F. (June 03, 2010). Inspiratory muscle training reduces the oxygen cost of breathing during exercise. Presentation 2097 at the 2010 Annual Meeting of the American College of Sports Medicine, Baltimore, Maryland; June 2-5.

This study determined if inspiratory muscle training can affect the oxygen cost of breathing during exercise. M cyclists (N = 16) completed six weeks of inspiratory muscle training using an inspiratory load of 50% (N = 8) or 15% [placebo control] (N = 8)of maximal inspiratory pressure. Before training, a maximal incremental cycle ergometer test was performed to determine VO2 and ventilation at multiple workloads. Pre- and post- training, Ss performed three separate four-minute bouts of voluntary hyperpnea (mimic), matching ventilation that occurred at 50%, 75%, and 100% of VO2max. During the mimic trials, target ventilation was maintained using visual feedback, matching the measured exercise tidal volume and breathing frequency.

Maximal inspiratory pressure significantly increased pre- to post-inspiratory muscle training in the training group and remained unchanged in the control group. Following inspiratory muscle training, the oxygen cost of breathing significantly decreased at all work levels. Heart rate during hyperpnea at 100%VO2max significantly decreased from pre- to post-training. No significant changes were shown in the control group.

Implication. Inspiratory muscle training significantly reduces the oxygen cost of exercise hyperpnea. A reduction in the oxygen requirement of the respiratory muscles during exercise may facilitate increased oxygen availability to the locomotor muscles.

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