About this trial

This is a clinical study enrolling individuals with chronic incomplete cervical (neck area) spinal cord injuries to test the effect of a breathing intervention called acute intermittent hypoxia (AIH). AIH provides air with low oxygen content for brief periods, alternating with room air with normal oxygen content. The study will compare the effect of AIH in individuals with and without obstructive sleep apnea (OSA, an abnormal breathing condition while sleeping). The purpose of this study is to learn about the effect of sleep apnea and low oxygen on muscle strength and lung function — e.g., does moderate to severe OSA decrease the breathing and motor strength response to AIH. All participants will do a 3-day AIH protocol (5 and 90 second hypoxic intervals alternating with 60-second room air intervals). One group will include participants with OSA; the other group includes participants that do not have sleep apnea. Outcomes will be assessed on breathing function (inspiration and expiration) as well as on grip strength. Blood will be collected to measure changes in markers for intermittent hypoxia.