By Betsy Hill and Roger Stark
There is growing concern about young people, especially high school students, not getting enough sleep. Many districts have responded by delaying school start times to give teenagers an extra hour of rest. While some cultures have historically downplayed the importance of sleep, the evidence is clear: children and adolescents need adequate sleep for learning, emotional regulation, and long-term brain health.
Sleep is not a passive state in which the brain simply switches off. Research shows the sleeping brain remains highly active, performing essential maintenance tasks and strengthening learning. During sleep, the brain clears metabolic waste and protein fragments that accumulate during the day, a process critical to maintaining a healthy brain. This cleansing is accomplished by cerebral spinal fluid flowing through spaces between neurons, removing byproducts that the waking brain does not have the energy to eliminate.
Sleep also plays a central role in memory consolidation. While awake, the brain continuously receives new sensory input and cannot effectively consolidate recently learned information. That consolidation largely occurs during sleep, when neural circuits revisit recent experiences and stabilize them. A small brain structure called the hippocampus is crucial early in this process: it activates recent memories and helps coordinate activity across the cortex so the synapses involved in learning are strengthened. Over time, these memories become less dependent on the hippocampus and are stored more permanently in cortical networks.
Different stages of sleep support different aspects of memory and brain plasticity. Non-REM sleep, especially deep or slow-wave sleep (SWS), appears to promote plasticity by allowing neurons to form new connections. REM sleep, on the other hand, supports stabilization: important connections are reinforced and less relevant connections are pruned, resulting in more efficient neural networks and stronger memories. Because a typical night includes several cycles that alternate between NREM and REM, both stages are essential for complete memory processing.
The distribution of sleep stages changes across the night. Deep slow-wave sleep tends to occur earlier in the night, while REM sleep periods lengthen toward morning. Shortening overall sleep duration or repeatedly interrupting sleep reduces time spent in both NREM and REM, impairing the full range of memory consolidation processes. So-called “all-nighters” are counterproductive: studying without sufficient subsequent sleep undermines the very memory processes required to retain what was learned.
Beyond memory, sleep deprivation harms many aspects of cognitive functioning. Lack of sleep degrades working memory, verbal learning, sustained and divided attention, inhibitory control, decision-making, and emotional regulation. These deficits translate into difficulty with problem solving, retaining verbal information, staying focused, and resisting impulsive or risky choices. Emotional memory formation also shifts when sleep-deprived, making it easier to form memories tied to negative emotions than positive ones.
Individual differences matter. People who have stronger inhibitory control and other executive functions when well-rested are better able to recruit those same brain systems under sleep loss than individuals with weaker baseline performance. This suggests that building strong cognitive skills in well-rested conditions provides a resilience advantage when sleep is limited.
For students and adults alike, the practical takeaway is straightforward: prioritize regular, sufficient sleep to support learning, memory consolidation, emotional balance, and overall cognitive health. Policies like later high school start times can help adolescents obtain the sleep they need, but individual habits—consistent bedtimes, limiting late-night screens, and avoiding all-night study sessions—also play a critical role.
Sleep is not optional for a healthy mind. It is a biologically necessary period for repair, consolidation, and preparation for wakeful learning and decision-making. A good night’s sleep supports better school performance, safer behavior, and a healthier brain over the long term. Here’s to making sleep a priority.
About the authors
Betsy Hill is President of BrainWare Learning Company, an organization that applies neuroscience to build learning capacity. An experienced educator, she has studied connections between neuroscience and education with leading experts. She has served as chair of the board of trustees at Chicago State University and teaches strategic thinking in the MBA program at Lake Forest Graduate School of Management. She holds a Master of Arts in Teaching and an MBA from Northwestern University.
Roger Stark is Co-founder and CEO of BrainWare Learning Company. For over a decade he has worked to make cognitive literacy skills training and assessment broadly accessible. He led development of BrainWare SAFARI, a comprehensive, integrated cognitive training tool delivered online and informed by decades of clinical collaboration and research. Stark’s work focuses on practical applications of cognitive science to improve learning outcomes.
This article was originally published by The Learning Counsel, a research institute and news media hub focused on providing context for the shift in education to digital curriculum.