STUDIES ON NAP SLEEP IN YOUNG STUDENTS - RELATIONSHIPS BETWEEN POLYGRAPHIC DATA AND THE OCCURRENCE OF DREAMS IN REPLACING NAPS

Background: Afternoon nap sleep was studied in 32 young male medical s tudents who take customary naps to replace loss in nocturnal sleep, Me thods: From 16 subjects, a group called dreamers was formed, and the o ther 16 individuals were grouped as non-dreamers. Polygraphic recordin gs lasting 30 min were done at a fixed time in the afternoon, and the relationship between these data and the occurrence of dreams was inves tigated. Results: We found that this replacing of nap sleep can adopt different sequences and relative durations of its phases, and can also show individual variations that have a systematic relationship with t he occurrence of dreams. It was observed that dreaming was closely rel ated to the appearance, during the first 10 minutes of the nap, of Sta ge I with Slow Eye Movements, interrupted by Sleep Onset REM Periods(S OREMPs) and, to a lesser degree, to phases IV and III of slow sleep. C onclusions: According to these findings, the existence of dreamers and non-dreamers depends upon the relationship between an internal sleep- waking rhythm, and an external rhythm imposed by the daytime resting-a ctivity schedule on the habit of dreaming, and, to a certain extent, o n the mental phenomena occurring between the generation of dreams and the moment of awakening.