Deep sleep can protect against neurodegeneration

Can prioritizing deep sleep be the key to protecting your brain? Scientists will reveal how sleep disorders accelerate neurodegeneration and why improving sleep can help slow cognitive decline.

review: Night Clock: Exploring how sleep protects against neurodegeneration. Image credit: Metamorworks/Shutterstock

Does better sleep help prevent or delay neurodegenerative diseases? Millions of people suffer from dementia around the world, but the relationship between sleep disorders and cognitive decline remains complicated.

A recent review published in the journal NeuronsUniversity of Washington scientists have investigated whether sleep disruption contributes to neurodegeneration and functions as an early symptom, or both. By understanding the protective mechanisms of sleep, they aimed to reveal ways to increase brain health and resilience.

Sleep and brain health

Sleep restores brain function, integrates memory and removes toxic waste. However, as people age, they sleep less, their sleep becomes fragmented, and deeper sleep decreases. This leads to a decline in cognitive function and an increased risk of neurodegenerative diseases.

Disruption of non-strength eye movement (NREM) sleep, particularly slow wave sleep (SWS), is associated with early amyloid beta (Aβ) plaque accumulation and tau protein entanglement, and features of Alzheimer's disease. Other neurodegenerative diseases, including Parkinson's disease, rewey intrabody dementia, and frontotemporal dementia, are often accompanied by sleep disorders several years before cognitive symptoms appear.

Despite these associations, whether sleep disruption promotes neurodegeneration reflects early pathology or both remain uncertain. Understanding the role of sleep in brain health can lead to early interventions to delay or reduce neurodegenerative diseases.

Current research

Researchers investigated how sleep disruption contributes to cognitive decline and analyzed molecular markers in both sleep patterns, brain activity, and both human and animal models.

They investigated changes in sleep, particularly in NREM and REM, and their effects on neurodegenerative pathways. They also investigated the role of sleep in the removal of metabolic wastes such as amyloid beta and tau, but noted contradictory evidence on whether sleep consistently increases clearance efficiency.

This study evaluated how prolonged awakening and fragmented sleep affect neural activity. Neuroinflammationand brain homeostasis. Findings from animal models suggested that lack of sleep promotes neurodegeneration by increasing protein deposition and disrupting neural function.

Furthermore, this study examined neurotransmitters such as orexin, dopamine, and acetylcholine in regulating the sleep-wake cycle and effects on disease progression. The researchers also investigated the genetic predisposition to sleep deprivation and analyzed variants such as APOE4, DEC2, ABCA7, and TREM2 to determine their role in cognitive decline.

Important insights

This study found that sleep destruction contributes to neurodegeneration and can also serve as an early symptom. Deprivation of sleep was associated with increased accumulation of neurotoxic proteins, impaired clearance, and increased neural activity, causing inflammation and oxidative stress.

In both human and animal models, reduced fragmented and reduced wave sleep correlated with changes in early neurodegeneration. People with genetic predispositions such as APOE4 carriers experienced more serious sleep disorders and a higher risk of dementia.

Different neurodegenerative disorders showed clear sleep patterns. Alzheimer's disease was associated with sleep fragmentation, whereas Parkinson's disease and frontotemporal dementia were often accompanied by excessive daytime drowsiness and REM sleep behavioral disorders.

Sleep improvements – behavioral changes, pharmacological interventions, or sleep therapy – allow neurodegenerative processes in models. Enhanced slow wave sleep reduced the burden of amyloid in animal studies and improved cognitive function.

However, researchers have focused on knowledge gaps, particularly when distinguishing causal relationships from correlations in human research. Sleep disorders are associated with neurodegeneration, but further research is needed to determine whether sleep interventions can delay the onset of a disease.

Conclusion

This study strengthens the important role of sleep in brain health, suggesting that sleep disorders may promote neurodegeneration rather than simply accompanying it. Sleep quality, especially improving deep sleep, can help protect against cognitive decline. Although further research is needed to validate sleep-centered treatments in humans, prioritizing sleep health may be essential to reduce the risk of neurodegenerative diseases.