Mild Intermittent Hypoxia and Its Multipronged Effect on Sleep Apnea
Trial Parameters
Brief Summary
Mild intermittent hypoxia (IH) initiates sustained increases in chest wall and upper airway muscle activity in humans. This sustained increase is a form of respiratory plasticity known as long-term facilitation (LTF). Repeated daily exposure to mild IH that leads to the initiation of LTF of upper airway muscle activity could lead to increased stability of the upper airway. In line with PI's laboratory's mandate to develop innovative therapies to treat sleep apnea, this increased stability could ultimately reduce the continuous positive airway pressure (CPAP) required to treat obstructive sleep apnea (OSA) and improve compliance with this gold standard treatment. Improved compliance could ultimately serve to mitigate those comorbidities linked to sleep apnea. Moreover, in addition to improving CPAP compliance numerous studies indicate that mild IH has many direct beneficial effects on cardiovascular, neurocognitive and metabolic function. Thus, mild IH could serve as a multipronged therapeutic approach to treat sleep apnea. In accordance with this postulation, our proposal will determine if repeated daily exposure to mild IH serves as an adjunct therapy coupled with CPAP to mitigate associated co-morbidities via its direct effects on a variety of cardiovascular, metabolic and neurocognitive measures and indirectly by improving CPAP compliance. Modifications in autonomic (i.e. sympathetic nervous system activity) and cardiovascular (i.e. blood pressure) function will be the primary outcome measures coupled to secondary measures of metabolic and neurocognitive outcomes.
Eligibility Criteria
Inclusion Criteria: * Body mass index \< 40 kg/m\^2. * 18 to 60 years old. * Newly diagnosed sleep apnea (i.e. apnea/hypopnea index \< 100 events per hour - average nocturnal oxygen saturation \> 85 %) that has not been treated. * Diagnosed with prehypertension or Stage 1 hypertension as categorized by the American Heart Association * Not pregnant. * Normal lung function. * Minimal alcohol consumption (i.e. no more than the equivalent of a glass of wine/day) * A typical sleep/wake schedule (i.e. participants will not be night shift workers or have recently travelled across time zones). * For spinal cord injured participants (Aim-2): incomplete spinal cord lesions at C3 or below and above T12 (greater than 36 mos. post-SCI) without joint contractures but with signs of voluntary ankle, knee and hip movements and the ability to ambulate at least one step without human assistance. Exclusion Criteria: * Any disease other than high blood pressure and sleep apnea. * Medications for high blood