 Although many studies have investigated the clinical importance of sleep apnea on rapid eye movement (REM) and non-REM (NREM) sleep, the relationship between behavioral performance and apneic events during different sleep phases remains unclear. In the present study, we sought to investigate the effect of sleep phase fragmentation due to sleep-disordered breathing (SDB) during REM and NREM on the vigilance and sustainability of attention based on psychomotor vigilance task (PVT) performance.