Mind Over Matter: How the glymphatic system brain detox protects brain health

Obstructive sleep apnea (OSA) is a sleep disorder characterized by frequent interruptions in breathing during sleep, depriving the brain of oxygen. This disruption often results in loud snoring, chronic daytime fatigue, brain fog, morning headaches, memory issues, and difficulty concentrating. OSA is one of several sleep disorders that can impact brain health.

An estimated 30 million adults in the U.S. are affected by OSA, yet only 6 million have been diagnosed—leaving 80% undiagnosed [6]. Why does this matter? Untreated OSA not only increases the risk of heart attack and stroke but has also been linked to impaired glymphatic function [7, 8]. OSA and other sleep disorders are linked to a variety of health conditions, including cardiovascular and neurodegenerative diseases. OSA is also strongly associated with a heightened risk of developing dementia [9]. A meta-analysis found that individuals with OSA were 26% more likely to experience significant cognitive decline or dementia within 3 to 15 years [10].

Interestingly, research suggests that the standard treatment for OSA—continuous positive airway pressure (CPAP)—can improve cerebrospinal fluid (CSF) flow and glymphatic function in both human and animal models [11, 12]. OSA leads to reduced glymphatic clearance, which contributes to the buildup of neurotoxic proteins such as amyloid-beta and tau. These findings underscore two key insights: first, CPAP therapy may enhance glymphatic function in individuals with OSA, potentially lowering their risk of developing dementia. Second, glymphatic function could play a far more significant role in safeguarding against cognitive decline than previously understood.

Research indicates that the glymphatic system’s ability to clear waste effectively declines with age, which contributes to the buildup of harmful toxins associated with an increased risk of Alzheimer’s disease [13, 14]. Amyloid beta accumulation, a hallmark of Alzheimer's disease, is one of the key toxic proteins that builds up when glymphatic clearance is impaired. Studies show that glymphatic clearance is significantly reduced in Alzheimer's patients compared to healthy controls, leading to greater amyloid beta accumulation and neurodegeneration. This impaired glymphatic function in aging brains negatively affects brain function and cognitive health, contributing to the progression of neurodegenerative diseases. This system plays a vital role in removing reactive oxygen species (ROS) and pro-inflammatory cytokines—compounds that can trigger chronic inflammation, also known as inflammaging, and lead to other age-related neurodegenerative diseases [15]. Supporting good sleep and healthy routines is essential for the well-being of older adults, as sleep quality directly impacts brain health.

Another concern is that as we age we also experience a decline in NREM sleep, which is critical for proper glymphatic function. Inadequate sleep during midlife has been linked to increased risk of cognitive decline and amyloid beta accumulation, further elevating the risk of dementia. Therefore, preserving or enhancing NREM sleep in older adults is critical for maintaining cognitive function. Age group-specific sleep recommendations are important, as sleep needs vary throughout life, and following these guidelines supports optimal brain health. Interestingly, studies of centenarians show that individuals aged 85–105 retain similar levels of NREM sleep as young adults aged 20–30. This preservation of deep sleep may be attributed to the adherence to strict, consistent sleep schedules [16]. Additional research underscores that maintaining a regular sleep routine is a stronger predictor of longevity than sleep duration alone [17].

Deep sleep is essential for metabolite clearance and solute clearance from the brain, as it activates the glymphatic system to remove waste products. The glymphatic system plays a crucial role in clearing harmful proteins and toxic proteins, such as amyloid beta and hyperphosphorylated tau, which are associated with Alzheimer’s disease. Effective waste removal depends on fluid movement, the exchange between cerebrospinal fluid (CSF) and interstitial fluid, and the expansion of the extracellular space during sleep. Amyloid beta and tau proteins tend to accumulate in the brain parenchyma, but the glymphatic system helps clear these aggregates to support brain health. The glymphatic system is analogous to the lymphatic system found elsewhere in the body, and cervical lymphatic vessels are important pathways for draining metabolic waste from the brain. The nervous system, including glial cells and brain cells, is integral to glymphatic function and brain detoxification.

Optimizing glymphatic function starts with supporting deep, restorative sleep, and these science-backed strategies can help you achieve both:

Gravity plays a role in the movement of CSF within the brain, which suggests that sleep position may influence the brain's ability to remove waste. While further research is needed, early studies indicate that glymphatic transport—responsible for clearing waste from the brain—is more effective when sleeping on your left side compared to sleeping on your back or stomach [18]. Notably, individuals with dementia have been observed to spend more time sleeping on their backs than those without the condition [19].

Poor sleep quality has been linked to impaired waste removal in the brain [20]. While many factors can disrupt sleep, one of the most common is screen time and light exposure before bed. Research reveals that 9 out of 10 Americans use a device before bedtime [21]. However, more interactive devices that emit blue light like smartphones and computers, when used within an hour of sleep, make it harder to fall asleep and leave individuals feeling less refreshed.

To improve normal sleep patterns, consider implementing these simple changes: create a completely dark sleeping environment—even minimal light can disrupt sleep quality [22]—and limit exposure to blue light-emitting screens at least one hour before bed. 

Research suggests that alcohol consumption affects glymphatic clearance in the brain, a process crucial for removing waste. In mice, medium to high doses of alcohol inhibited this clearance, while low doses showed a slight improvement in activity [23]. This finding may help explain why older adults who abstain entirely or consume alcohol heavily are at a higher risk of dementia compared to those who drink occasionally and in moderation [24]. While this is certainly not an endorsement to drink more, it does suggest that an occasional glass of wine with friends may not be all bad. 

L-theanine, a key ingredient in our sleep supplement, Restore, has been shown to increase NREM sleep by 20.6% (particularly when combined with GABA), which is necessary for optimal glymphatic function [25, 26]. L-theanine has been shown to reduce norepinephrine levels and may allow CSF to flow more freely to support enhanced waste removal in the brain [27].

Exercise not only enhances blood circulation but also supports healthy glymphatic function. Research indicates that aerobic activities, such as running, significantly improved glymphatic clearance, reduced amyloid beta buildup, and lowered neuroinflammation in mice [28].

Omega-3 fatty acids are well-known for their anti-inflammatory and neuroprotective properties [29], but recent research has uncovered another promising benefit: omega-3s may enhance glymphatic function, aiding in the clearance of amyloid beta from the brain in mice. This finding offers the potential for slowing or even preventing the onset of Alzheimer’s disease [30].