Upper airway resistance syndrome (UARS) is a condition that was first identified and described at Stanford University. It is very similar to obstructive sleep apnea (OSA) in that the soft tissue of the throat relaxes, reduces the size of the airway, and results in disturbed sleep and consequent daytime impairment, including excessive daytime sleepiness.
Although the increase in upper airway resistance is not enough to meet criteria of the sleep disordered breathing that define obstructive sleep apnea, the resulting increase in breathing effort does cause a brief awakening from sleep that is often undetected by the affected individual. When this scenario repeats throughout the night, sleep is impaired, just like in obstructive sleep apnea.