HOT TOPICS: Autonomic Dysreflexia and Orthostatic Hypotension: Can We Improve Both with Mild Intermittent Hypoxia? 1937

Mild intermittent hypoxia (MIH) is a relatively new intervention used to study many physiological systems and adaptations from the pathophysiology of sleep apnea, to ventilatory plasticity, to blood pressure (BP) regulation, and to motor function for those living with spinal cord injury (SCI). In humans, the neural plasticity following MIH has shown to increase breathing and BP with acute exposure, but also increase upper airway function in those with sleep apnea following repeated daily exposure. Considering improvements in breathing may improve autonomic function in those with SCI, reduce hypertension and improve upper airway function in those without SCI, we hypothesized that 8 days of MIH could improve autonomic dysreflexia (AD), orthostatic hypotension (OH) and sleep quality in individuals living with SCI. Additionally, we are exploring the potential impact of MIH on mitochondrial and microvascular function as these may impact autonomic control over BP. Finally, we wanted to explore if ventilatory plasticity (i.e., long-term facilitation and progressive augmentation of minute ventilation) on day 1 and day 8 of MIH was related to changes in sleep and upper airway function. Thus, the purpose of this project is to investigate the effects of MIH on AD, OH, mitochondrial capacity, sleep apnea severity (apnea hypopnea index [AHI]), ventilatory plasticity and upper airway collapsibility in individuals with motor incomplete SCI. This symposium is to present preliminary data from our ongoing trial.