About this trial

This is a trial to test the effect of repeatedly breathing air with low oxygen content for brief periods, alternating with breathing room air with normal oxygen content (acute intermittent hypoxia: AIH) combined with training breathing muscles to determine if their combined effect on breathing function is better than that achieved with either intervention alone. If included in this trial, the participant will complete 4x5-day interventions of 1) AIH, 2) breathing muscle strength training, 3) AIH and breathing muscle strength training, and 4) inactive intervention (sham AIH breathing room air) - not intended to have a therapeutic effect - used in a controlled trial for comparison to the active intervention. The order in which the interventions will be administered will be randomly determined. The intervention periods will be followed by a 3-week period without any intervention, during which clinical tests will be performed at 1 day, 3 days, and 1 week after the intervention.