SUBJECTIVE SLEEP NEED AND DAYTIME SLEEPINESS IN ADOLESCENTS

ABSTRACT Objective: To analyze the contribution of subjective sleep need for daytime sleepiness in adolescents, and to compare questions about sleep, age and body mass index between adolescents who considered to sleep enough and those who reported the need for more sleep. Methods: This is a descriptive, epidemiological and cross-sectional study. Data collection was performed in August 2016, with 773 adolescents aged 14-19 years old, from Paranaguá, Paraná, Southern Brazil. The analysis included the following variables: time in bed, half-sleep phase, sleep need, social jetlag, daytime sleepiness, body mass index and physical activity. Results: The prevalence of adolescents with subjective need for sleep was 73.0%, with an average need of 1.7 extra hours of sleep. These adolescents woke up earlier (p<0.001) and slept less on school days (p<0.001). The need for more sleep was associated with higher daytime sleepiness scores (rho=0.480; p<0.001) and with later half-sleep phase (rho=0.200; p<0.001). No correlation was identified between the sleep need and time in bed (rho=-0.044; p=0.225). The subjective sleep need was the variable with the greatest explanatory power for daytime sleepiness (24.8%; p<0.001). In addition, the less adolescents practiced physical activity, the higher their daytime sleepiness scores (rho=-0.117; p<0.001). Conclusions: The subjective sleep need has an important role in explaining daytime sleepiness among adolescents. Adolescents who needed to sleep more reported waking up early and experienced sleep deprivation during class days; they also woke up later on the weekends and experienced more daytime sleepiness, compared to those who believed they had enough sleep.

摘要 研究目的：分析青少年主观睡眠需求（subjective sleep need）对日间嗜睡（daytime sleepiness）的影响，并对比自认睡眠充足与报告存在额外睡眠需求的青少年在睡眠相关问题、年龄及身体质量指数（body mass index，BMI）方面的差异。
方法：本研究为描述性流行病学横断面研究。研究于2016年8月开展，共纳入巴西南部巴拉那州帕拉瓜纳市的773名14~19岁青少年作为研究对象。本次分析纳入的变量包括：就寝时间、睡眠半程点（half-sleep phase）、睡眠需求、社交时差（social jetlag）、日间嗜睡、身体质量指数以及体力活动水平。
结果：存在主观睡眠需求的青少年占比为73.0%，其平均额外睡眠需求为1.7小时。该类青少年起床更早（p<0.001）且上学日睡眠时间更短（p<0.001）。更高的睡眠需求与日间嗜睡评分升高（rho=0.480；p<0.001）以及睡眠半程点延后（rho=0.200；p<0.001）存在相关性。未发现睡眠需求与就寝时间存在相关性（rho=-0.044；p=0.225）。主观睡眠需求是解释日间嗜睡的最具影响力的变量（解释度为24.8%；p<0.001）。此外，青少年体力活动水平越低，其日间嗜睡评分越高（rho=-0.117；p<0.001）。
结论：主观睡眠需求在解释青少年日间嗜睡方面具有重要作用。与自认睡眠充足的青少年相比，存在额外睡眠需求的青少年报告称其起床更早且上学日存在睡眠剥夺；同时其周末起床时间更晚，日间嗜睡程度也更严重。