Effect of chronic sleep restriction on sleepiness and working memory in adolescents and young adults

Objectives: To test the feasibility of using a home-based sleep restriction protocol in adolescents and young adults; and to examine the different effects of chronic sleep restriction on a subjective sleepiness scale and working memory task in adolescents and young adults. Method: Twenty adolescents (ages 13-16 years) and 20 young adults (ages 18-20 years) underwent a 2-week home-based sleep manipulation protocol consisting of a week of 5 school days with 8 hr spent in bed per night and another week of 5 school days with 6 hr spent in bed per night. The protocol used a counterbalanced crossover experimental design. Subjective sleepiness was scored by the participant each morning, and working memory tests were administered during the weekend corresponding to each experimental week. Results: Adherence to the prescribed protocol was similar in the two groups, and both groups achieved the desired differences in total sleep duration across the two sleep conditions. Subjective sleepiness scores significantly increased in young adults after sleep restriction, but were not accompanied by significant changes in working memory. However, reaction times during simple verbal and arithmetic working memory tasks increased among adolescents after sleep restriction, without affecting accuracy on task, and without eliciting increases in subjective sleepiness scores. Conclusion: Mild sleep restriction for 5 days impairs reaction times during working memory tasks in adolescents in the absence of increased perception of sleepiness.