While You Were Sleeping: The Brain’s Secret Work

Sleep is one of the most important, yet least understood, biological processes. Even though we spend about a third of our lives doing it, the reason we sleep has remained a mystery. Modern science has helped us get closer to an answer, showing us that not only is sleep not mere rest, but it is a complex and dynamic process necessary for physical, emotional and cognitive health.

Fundamentally, sleep may have a replenishing purpose. Sleep also allows the brain to recover its levels of energy, suggesting that it may play a critical role during normal waking hours in the brain’s ecology of efficient uses of energy and resources ( (“Why Sleep?”).. It's not just about physical rest, but also biochemical re-balancing, and clearing metabolic waste from the brain. Throughout the stages of sleep, particularly during the slow-wave and REM phases, neurons are effectively reset, helping the brain to perform at its peak on waking.

The fact that sleep is universal across animal species suggests that it has deep evolutionary origins. As discussed in “Why We Sleep? A Manifesto in Defense of Sleep”, every species we know of sleeps in one form or another, and this commonality suggests that the advantages of sleep were highly preserved across the course of evolution. The article maintains that, not simply a passive or nonfunctional state, sleep actively supports survival by enhancing alertness, response time, and adaptation.

Research has also concentrated on the cognitive and developmental significance of sleep. In an article titled “The Functions of Sleep,” the book attempts several theories, such as memory consolidation & neural plasticity. Research also indicates that sleep is the time of day when the brain arranges and synthesizes information absorbed throughout the day, leading to better short-term and long-term memory. In addition, sleep facilitates brain restructuring which is necessary for learning new tasks and behaviors. Another article “The Developing Brain and the Importance of Sleep” emphasizes the significance of sleep during early development. It is also a good reminder that not all stages of sleep are created equal, and that they are related to neurological growth and developmental milestones in different ways, giving additional power to the idea that sleep is not only for rest, but for growth and transformation.

The punishment when we don’t sleep enough is fittingly grim. In “Sleep Deprivation and Neurological Disorders,” researchers detail how chronic sleep dislocation raises the risk of neurological issues like Alzheimer’s disease, depression, stroke and other problems. The article references how sleep assists in clearing toxic beta-amyloid and other such substances from the brain, whose buildup has been associated with neurodegenerative diseases. Partial or inadequate sleep impairs this clearance mechanism, which may accelerate neurologic decline.

The academic literature also supports the wider physiological and psychological aspects of sleep. The Oxford Handbook of Sleep and Sleep Disorders edited by Charles M. Morin et al. With this volume of The Oxford Handbook of Sleep and Sleep Disorders, the editors attempt to provide a comprehensive overview of the broad scope of the modern sleep field. They chart how sleep disruptions impact not only cognition but also immune function, metabolism and emotional regulation. Patrick McNamara’s The Neuroscience of Sleep and Dreams takes this riff further, explaining how various components of sleep (REM sleep, for example) are entwined with the processing of emotion, and even creativity. When we have concerns or problems that are bothering us, we often are able to work through them outside of our waking conscious awareness.” Ultimately, dreams can be psychologically beneficial, in that they may help people work through nagging thoughts and feelings, he says, building up their mental resilience.

In a culture that so frequently values getting things done over taking care of ourselves, the ramification of our neglect for sleep is huge. The combined evidence of neuroscience, developmental psychology and clinical medicine makes it unquestionable: Sleep is not a luxury. It’s a complex biological requirement that forms the foundation of all human health and performance. Now, in the face of a burgeoning mental health crisis, a learning crisis and a chronic disease crisis within the developed world, prioritizing sleep may be one of the most rational, science-based and value-creating changes we can make.

References:

1. Sleep Deprivation and Neurological Disorders.” Peer-Reviewed Article.

2. “The Functions of Sleep.” Peer-Reviewed Article.

3. “The Importance of Sleep for the Developing Brain.” Peer-Reviewed Article.

4. “Why Sleep?” Peer-Reviewed Article.

5. “Why We Sleep? A Manifesto in Defense of Sleep.” Peer-Reviewed Article.

6. McNamara, Patrick. The Neuroscience of Sleep and Dreams. Cambridge University Press.

7. The Oxford Handbook of Sleep and Sleep Disorders. Oxford University Press.