Abstract Introduction Adolescence is a critical developmental period characterized by biologically driven shifts in circadian rhythms and increasing academic and social demands, often resulting in later sleep timing, shorter sleep duration, and heightened stress related arousal. While inadequate sleep is linked to global cognitive functioning, the specific associations between sleep dimensions (duration, timing, pre sleep cognitive arousal) and cognitive domains fundamental to academic success and daily functioning remain unclear. Objective: To examine the differential associations between sleep duration, sleep timing, and pre sleep cognitive arousal with cognitive flexibility, processing speed, sustained attention, and attentional shifting in typically developing adolescents. Understanding these relationships is essential for developing targeted sleep based cognitive improvement interventions. Methods Forty nine adolescents (Mean age = 13.38 years, SD = 1.30 years) participated. Sleep duration and timing were measured over four consecutive school nights using wrist actigraphy and daily sleep logs. Pre sleep arousal was assessed with the Pre Sleep Arousal Scale. Cognitive performance was evaluated using a battery designed to assess complex and simple cognitive processes, including cognitive flexibility, processing speed, sustained attention, and attentional shifting. Results Findings revealed differential associations across sleep and cognitive dimensions. Later sleep timing and higher pre sleep cognitive arousal were associated with poorer fluid cognitive processes, including flexibility and attention, whereas adequate sleep duration was robustly associated with better general executive function and faster processing speed. Conclusion Sleep health relates to multiple cognitive domains in distinct ways. A key limitation of the present study is its cross sectional design, which precludes causal inference. Future experimental studies should independently manipulate sleep duration, timing, and pre sleep arousal (e.g., sleep extension; circadian phase advancement via earlier bed/wake times and morning light; and pre sleep cognitive strategies), use objective sleep measures, and assess domain specific outcomes. Implications for schools: Scheduling and programming that support earlier and consistent sleep timing, reduce pre sleep cognitive arousal, and support adequate sleep duration align with the observed associations between sleep health and cognitive flexibility, attention, and processing speed. Support (if any) NSERC Discovery Grant RGPIN-2021-03363;Canadian Institute of Health Research, Grant#166148 to Reut Gruber.
Gruber et al. (Fri,) studied this question.