SLEEP AND NAPPING IN YOUNG SHIFTWORKERS - A 5-YEAR FOLLOW-UP

The present study examined sleep characteristics in young workers who entered rapidly rotating shiftwork for the first time and stayed on sh ifts for 5 years. Data were collected when the subjects had shiftwork experience of approximately 1.5, 3.5 and 5.5 years and a mean age of 2 2, 24 and 26 years. Data are presented showing significant differences in the main sleep durations between situations within the shift cycle and a small reduction in overall sleep over the observed period, prim arily due to a sleep reduction on afternoon shift days. Data on sleep quality did not show any change over this early period of shiftwork ex posure. In addition, napping strategies did not change, with the excep tion of a small increase in those taking naps on night-shift days betw een 1.5 years and 3.5 years of shiftwork exposure. At all the observed phases there were more young shiftworkers taking a nap on the morning shift days than on the night-shift days. The data suggested that redu ced sleeps on morning and night-shift days were not compensated by tak ing a nap, but rather with an increase in main sleep duration on after noon shift days and days off. A weak tendency for individuals to be re latively long or shore sleepers irrespective of sleep conditions could be seen.