Longer Sleep Duration Enhances Cognitive Performance in Adolescents

Recent research from the UK and China indicates that adolescents who acquire more sleep, particularly from an earlier bedtime, tend to demonstrate improved brain function and excel in cognitive assessments. The study analyzed data from the extensive Adolescent Brain Cognitive Development (ABCD) Study, involving over 3,200 US teenagers aged 11-12, equipped with fitness trackers like Fitbits to objectively monitor sleep patterns. Results revealed that adolescents could be categorized into three groups based on their sleep habits:

• Group One: Approximately 39% of participants averaged about 7 hours and 10 minutes of sleep, going to bed and falling asleep latest, and waking earliest.
• Group Two: About 24% slept roughly 7 hours and 21 minutes with moderate sleep characteristics.
• Group Three: Around 37% slept an average of 7 hours and 25 minutes, generally sleeping earlier with lower heart rates during sleep.

Although school achievement scores did not vary significantly across groups, cognitive tests assessing vocabulary, reading, problem-solving, and focus showed that Group Three outperformed Group Two, which outperformed Group One. Additionally, brain imaging revealed that Group Three had greater brain volume and better brain function, whereas Group One had the smallest volume and poorest function.

Lower heart rates observed in the groups with longer sleep further indicated better health and sleep quality. Longitudinal data confirmed that these differences in sleep, brain development, and cognition appeared two years prior to and persisted two years after the initial assessment.

Professor Barbara Sahakian from the University of Cambridge emphasized the importance of sufficient sleep during adolescence, a critical period of brain development, noting that despite recommendations of 8-10 hours of sleep per night, many teens do not meet this target. The study highlights the impact of sleep habits on neurological and cognitive health, prompting further exploration into factors influencing sleep timing, such as digital device use and circadian rhythms.

The findings underscore that even modest differences in sleep duration can significantly influence brain structure and cognitive performance in adolescents, advocating for strategies to support healthier sleep habits during this vital developmental stage.