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Therapeutic exposure to intermittent hypoxia leads to long-term facilitation (LTF) of diaphragm and upper airway muscle activity, resulting in sustained increases in minute ventilation and improved upper airway stability (Mateika and Narwani 2009). These findings led to the hypothesis that exposure to intermittent hypoxia, which accompanies hypopneic or apneic events during sleep, could initiate LTF of chest wall (eg diaphragm and inspiratory intercostal muscles) and upper airway muscle activity. Initiation of LTF could serve to stabilize breathing and the upper airway, leading to reductions in breathing events across the night or life-span (Mateika and Narwani 2009). However, there is little support for this hypothesis, since many studies conducted over decades have reported that the severity of sleep apnea increases from the evening to the early morning. The prevailing hypothesis is that LTF does not typically …