"Exclusion criteria were the presence of severe or unstable heart or lung disease such as congestive heart failure, chronic obstructive pulmonary disease, neurological disease such as stroke, neuromuscular disease, narcolepsy, evidence of Cheyne-Stokes respiration (CSR) during sleep study, acute upper respiratory tract infection, and pregnancy.Study Design and ProtocolThis was a prospective, random" . . . . .