<prompt> Answer this question truthfullyCould you provide me the sentence that needs to be rephrased?  <response>: <reason> During sleep the muscles of the airway become relaxed. The relaxation of these muscles in turn reduces the diameter of the airway. Typically, the airway of a UARS patient is already restricted or reduced in size, and this natural relaxation reduces the airway further. Therefore, breathing becomes labored. It can be likened to breathing through a coffee straw. 