Why REM Sleep is Just as Important as Deep Sleep

Why ignoring your sleep tracker could cost you your brain health.

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My Longevity Experiment
November 19, 2024

The Most Important Stage of Sleep for Brain Health

A groundbreaking study from the University of Oslo, recently published in Nature Communications, is challenging traditional beliefs about which stage of sleep is most critical for clearing waste products from the brain. This discovery sheds new light on how the brain maintains its health during sleep.

The Vital Process of "Brainwashing"

The term "brainwashing" often carries negative connotations, but in this context, it refers to the essential biological process of clearing harmful waste products from the brain. According to researchers, this natural cleaning mechanism is crucial for maintaining brain health and may hold the key to preventing neurodegenerative diseases.

The study reveals that the blood vessels in the brain constrict and dilate in specific patterns during sleep. These movements play a pivotal role in driving the clearance of harmful proteins and other waste materials from the brain.

Potential Implications for Alzheimer's and Drug Delivery

Rune Enger, Associate Professor at the Letten Centre at the University of Oslo and the study’s senior author, explained the significance of these findings. "Our discoveries can help us find new ways to treat or even prevent Alzheimer's disease and other neurodegenerative diseases. These findings can also help to create strategies to deliver drugs to the brain more efficiently."

The "Brainwashing" Process in Action

Throughout the day, the brain generates waste products, including proteins such as beta-amyloid and tau. If these substances accumulate, they increase the risk of Alzheimer’s disease and other neurodegenerative conditions. Sleep provides an optimal environment for the brain to clear these harmful materials.

"The 'brainwashing' process is far more efficient when you are asleep than when you are awake, but the reason for this is not yet clear," Enger added.

Blood Vessel Dynamics During Sleep

Researchers observed that the brain's blood vessels, especially arteries, dilate and constrict in specific patterns during sleep. These movements influence the specialized channels surrounding the blood vessels, which facilitate the transport of waste and fluids out of the brain.

Using advanced laser microscopy, the researchers examined the brains of sleeping mice. They discovered that these vascular movements occur not only during deep sleep but also in REM sleep and even during brief awakenings.

All Stages of Sleep Play a Role

The findings challenge the long-held belief that deep sleep is the sole stage responsible for waste clearance. The study demonstrated that the brain’s cleaning process occurs throughout the sleep cycle, including REM sleep and short wakeful moments during the night.

During deep sleep, arteries dilate and constrict slowly. In REM sleep, arteries stay dilated before constricting quickly at the end of the cycle. Even during brief awakenings, similar constriction patterns occur.

Fluid Flow and Brain Health

These sleep-dependent vascular movements affect the size of the channels surrounding the blood vessels, which are critical for fluid transport. By widening and narrowing in sync with the blood vessels, these channels regulate the flow of fluids and molecules in the brain.

To further understand the process, the team used biomechanical computer modeling. Kent-Andre Mardal, a Professor in Mechanics at the University of Oslo, who led the modeling work, stated, "To sum up, we found that the artery dilations and constrictions, and the simultaneous changes in the channels around them had a big part to play in both the flow of fluids and the transport of substances in the brain."

Implications for Neurodegenerative Diseases

This research highlights the potential of targeting blood vessel dynamics during sleep to enhance brain waste clearance. Such strategies could improve drug delivery to the brain and reduce the risk of neurodegenerative diseases.

What This Means for Sleep Tracking

Traditionally, deep sleep was considered the most critical stage for brain waste removal. However, this study indicates that both deep sleep and REM sleep contribute significantly to this process. Maximizing time spent in these stages is essential for optimal brain health.

Using a fitness tracker to monitor sleep stages could help individuals identify deficiencies in deep and REM sleep, allowing them to take steps to improve their sleep quality. With sleep playing such a vital role in brain health, this research offers yet another compelling reason to prioritize restorative sleep.

My Deep Sleep Video: https://bit.ly/41TQemy

Study Links:

https://bit.ly/3n4tnWo

https://bit.ly/3n50Wb1