University of California – Davis researchers want to answer the question, “How much sleep do adolescents need?” The Enterprise reports.

Data from their most recent longitudinal sleep study is still being evaluated, Campbell said, but they have seen “a strong relation between prior sleep duration and daytime sleepiness evaluated with the multiple sleep latency test,” Campbell explained, meaning that “participants were more likely to fall asleep during (a) 20-minute nap opportunity, and they were more likely to do so more quickly.”