Intermittent Hypoxia and Balance Control

During the intermittent hypoxia session, participants will be sitting during the entire breathing protocol. Hypoxic air will be inhaled through a mask connected to a two-way non-rebreathing valve, which will itself be connected to a 5-liter non-diffusing gas bag (Hans Rudolph, Inc, USA). The rebreathing bag will be connected to a certified medical grade gas tank containing 11% oxygen and a balance of nitrogen. The intermittent hypoxia protocol will consist of eight 4-min cycles of breathing hypoxic air interspersed with normoxic cycles breathing room air. After four min of hypoxia, participants will be switched back to breathing room air until resaturation, which takes approximately one minute. Once arterial oxygen saturation reaches baseline levels, participants will be switched back to breathing hypoxic air, beginning the next hypoxic cycle.

During the sham condition, compressed air (21% oxygen) from a gas tank will be delivered throughout the protocol instead of 11% oxygen. Participants will not receive information about which condition (Intermittent hypoxia or sham) they are experiencing during the trials.