Deep Sleep Cleans The Brain And Protects Against Neurological Disorders, New Studies Reveal

Recent studies suggest that deep sleep plays a critical role in protecting the brain from serious health issues. One study reveals that deep sleep helps clear waste from the brain, similar to how a dishwasher cleans dirty dishes. This finding could explain how sleep impacts cognitive function and why sleeping pills may interfere with this process.

Professor Maiken Nedergaard from the University of Rochester and the University of Copenhagen, who led the research, explains that norepinephrine, a neurotransmitter and hormone, triggers blood vessels to contract, creating rhythmic pulses that help flush out waste from the brain. “It’s like turning on the dishwasher before you go to bed and waking up with a clean brain,” she said.

The brain has a built-in waste removal system known as the glymphatic system. This system circulates fluid through the brain and spinal cord to clear out harmful proteins that form sticky plaques. These plaques are linked to neurological conditions like Alzheimer’s disease.

Until now, scientists didn’t fully understand what drives this waste removal process. To explore this, Nedergaard and her team studied mice during deep sleep, focusing on the connection between norepinephrine and blood flow in the brain. They found that norepinephrine waves are connected to changes in blood volume, which in turn trigger the flow of brain fluid to clear out waste.

The study’s lead author, Natalie Hauglund of the University of Copenhagen and the University of Oxford, likened norepinephrine to the conductor of an orchestra. She explained, “There’s a harmony in the constriction and dilation of the arteries, which drives the cerebrospinal fluid through the brain to remove waste products.”

In a separate part of the study, the researchers tested zolpidem, a common sleep aid, on mice. They found that the norepinephrine waves during deep sleep were 50% lower in the zolpidem-treated mice than in the naturally sleeping mice. Although the zolpidem-treated mice fell asleep faster, the fluid transport in their brains dropped by more than 30%. This suggests that sleep aids may disrupt the brain’s natural waste-clearing process.

The researchers published their findings in the journal Cell, highlighting the importance of understanding how sleep medications affect brain health. Hauglund noted, “It’s crucial for people to know if they are getting the full benefits of sleep. If not, they should be aware of it to make informed decisions.”

While these findings apply to mice, they are likely relevant to humans as well, since we have a similar glymphatic system. Further testing is needed to confirm these results in humans.

Additionally, lack of sleep may lead to more than just grogginess. Another recent study published in Proceedings of the National Academy of Sciences found that sleep deprivation weakens the brain’s ability to suppress unwanted memories. The study suggests that insufficient sleep impairs the brain’s defense mechanisms, allowing intrusive thoughts to flood the mind. This research underscores the importance of sleep in maintaining both mental and cognitive health.