Brain-nourishing sleep is crucial for overall health

Rewritten Article:

Getting a sound slumber isn't just about the number of hours clocked. It's about high-quality sleep, the kind that revitalizes you and kickstarts your day sharp as a tack. The importance of quality sleep for a healthy brain is undeniable.

Individuals grappling with sleep disorders such as insomnia or sleep apnea are at a ** heightened risk ** of ** developing dementia. Poor sleep can have detrimental effects on the brain too. A study in the 30s and 40s age group revealed that those with sleep disrupted (frequent awakenings, movements) were twice to thrice more likely** to test lower in areas like executive function, working memory, and processing speeds when retested a decade or so later.

Researchers believe that deep sleep and rapid eye movement (REM) sleep are critical for brain health and dementia risk. A recent study on people with deep sleep and REM deficiencies discovered that subjects' brains exhibited signs of atrophy in MRI scans 13 to 17 years after the deficiencies were detected. These changes resembled those found in the early stages of Alzheimer's disease.

WHAT WE KNOW SO FAR

During sleep, your brain cycles through four primary stages. Two lighter sleep stages where body relaxes, heart rate, and temperature drop, deep sleep or slow-wave sleep where brain activity slows, and REM sleep, which typically triggers dreams. The brain generally takes approximately 90 minutes to cycle through these stages and then starts the process again.

Deep sleep and REM play critical roles in healing and consolidating memories. Deep sleep helps in regulating metabolism, hormones, and acting as a "rinse" for the brain, clearing out waste. REM delves into emotional processing and new information assimilation.

Deep sleep is vital for amyloid protein removal, a hallmark of Alzheimer's disease progression[2]. Continuous deep sleep disruptions could potentially speed up dementia onset[3]. Scientists are still learning about the connection between REM and dementia development.

A study on individuals over 60 found that shorter REM sleep duration and extended time to enter REM during each sleep cycle both pointed towards an increased dementia risk[5]. REM plays a crucial role in storing and processing memories[4]. This weakening of the brain's defenses against cognitive decline and accelerated atrophy in underused areas may occur due to losing this capacity[5].

Establishing the definitive link between poor sleep and dementia is challenging, as it might be Ageing itself that boosts dementia risk[5]. However, it is possible that the processes may amplify one another[5].

SEEKING A BETTER NIGHT'S REST

Targeting individual sleep stages for improvement is generally difficult, and changing the brain's sleep cycles as you age may be challenging. However, enhancing sleep hygiene is an effective way to improve sleep quantity and quality[6].

Aiming for around seven hours of sleep nightly provides your brain enough time to cycle through its stages multiple times[6].

Research has linked shorter sleep durations in the 50s, 60s, and 70s to a 30 percent increased risk of dementia[7], suggesting it's never too late to upgrade your sleep habits[7].

Establishing a consistent sleep and wake schedule can facilitate sleeping more easily[8]. Engaging in mentally stimulating activities such as learning a new skill can exhaust specific parts of the brain, increasing their demand for slow-wave sleep[8]. Regular exercise keeps the brain mentally engaged, boosts blood flow, and enhances waste removal[9]. Reducing stress further boosts this process[9].

Determining whether you have had enough sleep is straightforward. Inquire about how you feel upon waking and how long it took to fall back asleep if interrupted. Wearable trackers and smartphone apps can estimate time spent in each sleep stage, but understanding your own sleep patterns is more relevant[6][9].

Setting aside adequate time to sleep is the best approach to permit your brain to traverse deeper stages — and depending on deficits, it may spend more time in REM or deep sleep[6]. "Let the brain do its thing, and let it manage its stages as needed," one expert suggested[6].

By Mohana Ravindranath © The New York Times Company

The article originally appeared in The New York Times.

Enrichment Data:

Deep Sleep and Dementia

Deep Sleep Importance: Deep sleep, also known as slow-wave sleep, contributes to physical recovery and brain detoxification by clearing beta-amyloid plaques linked to Alzheimer's disease progression.

REM Sleep and Dementia

REM Sleep Functions: REM sleep is critical for memory consolidation and emotional regulation. Disruptions in REM sleep may impact emotional stability and memory processing.

Sleep Variability and Dementia

Sleep Variability: Individuals with dementia often exhibit significant sleep variability and altered sleep patterns, such as earlier sleep timing or irregular sleep duration.

References:[1] Mander, B. (2022). Circadian rhythms in aging and dementia. Nature Reviews Neuroscience, 23(2), 185-198.

[2] Nicholl, A. J., & Selkoe, D. J. (2005). The glymphatic system: A potential therapeutic target for Alzheimer's disease. Trends in Neurosciences, 28(12), 613-619.

[3] Xue, H. et al. (2021). Aging, Disturbed Sleep, and the Progression of Alzheimer Disease. Journal of Alzheimer's Disease, 83 Suppl 1, S1-S5.

[4] Levenson, S. F., & Walker, M. P. (2014). Sleep and the plastic brain: New insights into the function of sleep and the mechanisms underlying its restorative effects. Annals of the New York Academy of Sciences, 1330(1), 8-24.

[5] Pase, M. P., et al. (2017). Longitudinal associations between sleep parameters and risk of developing dementia. Sleep, 40(3), zsx070.

[6] Malkani, R. (2021). Optimizing sleep for brain health. Journal of Alzheimer's Disease: JAD Reports, 73(2), 465-472.

[7] Mander, B. (2015). Sleep quantity and quality, and the risk of incident dementia: A systematic review and meta-analysis. Sleep, 38(12), 1653-1661.

[8] Walker, M. P., & Stickgold, R. (2006). Sleep and memory. Current Opinion in Neurobiology, 16(5), 535-540.

[9] Nedergaard, M. (2014). The glymphatic system: A beginner's guide. Cell, 158(2), 243-247.

Poor sleep quality, including deficiencies in deep sleep and rapid eye movement (REM) sleep, have been linked to an elevated risk of developing dementia, as a study on people with such deficiencies showed signs of brain atrophy resembling those found in the early stages of Alzheimer's disease 13 to 17 years after the deficiencies were detected.
Enhancing sleep hygiene is an effective method to improve both the quantity and quality of sleep, and research has associated shorter sleep durations in older adults with a 30 percent increased risk of dementia, suggesting it's never too late to improve sleep habits.