Sleep apneic activity in a normal population.

One hundred subjects without any complaint of sleep disturbance were evaluated in the sleep laboratory for the presence of sleep apnea and sleep apneic activity (SAA). This sample, which had a representative proportion of women and men and a wide age distribution, included only subjects who were physically and mentally healthy and were not using any medication. None of the subjects had the clinical condition of sleep apnea, and only 12 percent of the subjects met the more liberal criterion for SAA. The prevalence of SAA was slightly higher in men than in women. SAA was positively and significantly correlated with increasing age. However, relative severity, as judged by the mean number of events and the duration of events, showed no consistent pattern in relation to age. Further, it was demonstrated that those subjects with SAA were significantly heavier than those without the activity. Neither smoking nor caffeine consumption was related to the presence of SAA. When the amount of each sleep stage was controlled for, SAA occurred significantly more often during REM sleep. A relatively small number of EEG arousals were related to SAA, with only about one-fifth of the events resulting in brief arousals.