Adolescent sleep patterns significantly impact brain development and cognitive ability
In a pioneering study examining the relationship between sleep patterns and adolescent brain development, researchers have revealed that young people who sleep longer and go to bed earlier show improved brain structure, neural connectivity, and cognitive performance compared to their peers with later bedtimes and shorter sleep duration – though even the best sleepers fall short of recommended sleep guidelines for their age group.
One of the largest studies to use device-based sleep measurements
A comprehensive new study examining objective sleep data from over 3,200 adolescents has found significant associations between sleep habits and brain development. The research, published 22 April 2025 in Cell Reports, represents one of the largest studies to use device-based sleep measurements rather than self-reported data, providing unprecedented insight into how sleep impacts adolescent cognitive development.
The international research team, led by scientists at Fudan University, Shanghai, and the University of Cambridge, analysed data from the Adolescent Brain Cognitive Development (ABCD) Study, the largest long-term study of brain development and child health in the United States.
“Regularly getting a good night’s sleep is important in helping us function properly, but while we know a lot about sleep in adulthood and later life, we know surprisingly little about sleep in adolescence, even though this is a crucial time in our development,” said Professor Barbara Sahakian from the Department of Psychiatry at the University of Cambridge, a co-author of the study.
Objective sleep measurement reveals three distinct patterns
Unlike previous research that relied on self-reported sleep data, this study used FitBit wristbands to collect objective measurements over a three-week period, tracking total sleep duration, sleep stages, heart rate during sleep, bedtime, and wake-up times.
Through sophisticated machine learning analysis, the researchers identified three distinct sleep patterns among the adolescents:
Group One (39% of participants) averaged 7 hours 10 minutes of sleep, with the latest bedtimes and earliest wake times.
Group Two (24% of participants) averaged 7 hours 21 minutes, with intermediate sleep characteristics.
Group Three (37% of participants) averaged 7 hours 25 minutes, with the earliest bedtimes and lowest heart rates during sleep.
“Even though the differences in the amount of sleep that each group got was relatively small, at just over a quarter-of-an-hour between the best and worst sleepers, we could still see differences in brain structure and activity and in how well they did at tasks,” Professor Sahakian emphasised. “This drives home to us just how important it is to have a good night’s sleep at this important time in life.”
Sleep quality directly impacts cognitive performance
When tested on cognitive tasks measuring aspects such as vocabulary, reading, problem-solving and focus, Group Three consistently outperformed Group Two, which in turn performed better than Group One.
Neuroimaging revealed corresponding differences in brain structure and function. Group Three showed the largest brain volumes and best brain connectivity, particularly in regions associated with memory and cognitive processing, while Group One had the smallest volumes and least optimal connectivity patterns.
First author Dr Qing Ma from Fudan University noted: “Although our study can’t answer conclusively whether young people have better brain function and perform better at tests because they sleep better, there are a number of studies that would support this idea. For example, research has shown the benefits of sleep on memory, especially on memory consolidation, which is important for learning.”
Sleep-brain connection persisted over time
Importantly, the researchers tracked these differences longitudinally, finding that the sleep-related brain differences and cognitive performance patterns remained consistent over a four-year period from ages 9-10 to ages 13-14.
In the study discussion, the authors noted: “Our findings support the close relationship between sleep, brain, and cognition, suggesting the potential to improve adolescent cognitive abilities by adjusting sleep patterns, possibly by falling asleep earlier and getting more sleep, which holds important practical and societal implications.”
The team also found that the group with better sleep profiles had lower heart rates during sleep, typically a sign of better health. The authors suggest this “heart-brain connection” warrants further investigation, as it may represent an important pathway connecting sleep quality to brain health.
Implications for adolescent health
While this research clearly demonstrates the benefits of better sleep habits, it also raises concerns that even the best-sleeping group averaged just 7 hours 25 minutes of sleep – well below the American Academy of Sleep Medicine’s recommendation of 8-10 hours for adolescents.
Senior author Dr Wei Cheng from Fudan University raised an important question for future research: “Given the importance of sleep, we now need to look at why some children go to bed later and sleep less than others. Is it because of playing videogames or smartphones, for example, or is just that their body clocks do not tell them it’s time to sleep until later?”
The research was supported by the National Key R&D Program of China, National Natural Science Foundation of China, National Postdoctoral Foundation of China and Shanghai Postdoctoral Excellence Program.
Reference
Ma, Q., Sahakian, B. J., Zhang, B., Li, Z., Yu, J.-T., Li, F., Feng, J., & Cheng, W. (2025). Neural correlates of device-based sleep characteristics in adolescents. Cell Reports, 22 Apr 2025. https://doi.org/10.1016/j.celrep.2025.115565
