engleski

Adolescent sleepiness on a double-shift school system: MSLT, subjective sleepiness and performance on morning and afternoon school week

Double-shift school system facilitates irregularities of sleep pattern and sleep duration in adolescents, which is inconsistent with sleep hygiene recommendations stating that adolescents should avoid large delay of bedtime and wake time, and large extension of sleep. Our previous studies indicated that the adolescents used the extension of main sleep on afternoon schedule to pay off the sleep debt accumulated during morning shift days. In this study we wanted to examine whether the levels of their sleepiness differed at the end of the school weeks with morning and afternoon schedule. Twenty-two secondary school students (12 females, modal age 16 yrs) participated in the study. They kept sleep-wake diaries, and wore wrist Actiwatch Score devices for two consecutive weeks. Half of the participants started the study on the morning shift week, and the other half on the afternoon shift week. They were also giving sleepiness ratings seven times a day on a five point Lykert type scale using the actigraph score option. On Fridays of both school weeks they came to laboratory for MSLT and performance measurements, which were taken four times at two-hour intervals. Performance measures used were speed and accuracy on the Search and Memory task with three levels of difficulty and on a 10-minute simple reaction time task. None of the sleepiness measures showed statistically significant difference between morning and afternoon schedule. Mean sleep latencies in both situations approximated 13 minutes, and subjective sleepiness ratings were very low, ranging from 1 to 3.5. Regardless of the school schedule, the sleep latencies showed an expected circadian effect, being shorter on the measurement points at 11:00h and 15:00h. The results of this study indicate that daytime sleepiness in adolescents attending school on a weekly rotating morning and afternoon shifts does not seem to differ between school weeks with different sleep opportunities.

adolescents; daytime sleepiness; double-shift schedule

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