Millions of individuals worldwide grapple with persistent sleep issues, with approximately 70 million people in the United States alone affected. These challenges pose significant health risks, including cognitive decline and dementia. Adults over 18 are advised to secure at least seven hours of quality sleep each night to mitigate these risks. Despite this recommendation, many adults continue to struggle with sleep disorders such as insomnia and sleep apnea. A recent study published in Nature Medicine highlights a concerning trend: the risk of dementia among Americans over 55 has more than doubled.
The brain's glymphatic system plays a crucial role in maintaining neurological health by removing "waste" associated with neurodegenerative diseases during sleep. This system operates efficiently due to synchronized oscillations occurring during sleep, as demonstrated in a recent mouse model study.
“Sleep allows the brain to go offline, shut down processing of the external world and focus on maintenance tasks, such as immune surveillance and removal of waste,” – Natalie Hauglund, PhD
During non-REM sleep, norepinephrine, a key neuromodulator, is released in slow cycles approximately every 50 seconds. This process is vital for powering the glymphatic system and ensuring the brain is ready for the new day. However, sleep aids can potentially obstruct these neuromodulators, disrupting this essential waste removal system.
“Sleep is crucial as it gives the brain time to perform homeostatic housekeeping tasks such as waste removal. On the contrary, sleep aids block the neuromodulators that drive the waste removal system and prevent the brain [from] properly preparing for a new day.” – (no attribution)
Despite ongoing research, no universally accepted explanation for the necessity of sleep exists as of 2025. Researchers continue to debate various theories, though consensus remains elusive.
“In the year 2025, there remains no accepted response on why we sleep. Different researchers make different claims and sometimes these are the same and sometimes they are different. We know healthy sleep makes us healthy and poor sleep makes us unhealthy.” – Segil
The study also suggests that alterations in the balance of the glymphatic system could have potential cellular and clinical consequences. It is important to note that these findings are based on animal studies, and experts urge caution when extrapolating these results to humans.
“This study suggests that alterations in this tight balance have potential cellular and perhaps clinical consequences. While fascinating, we must remind ourselves that this is an animal study and, as is often the case, extrapolation of animal data to humans must be done cautiously. Nonetheless, it does give clinicians a phenomenon that is deserving of some discussion.” – Peter G. Polos, MD, PhD, FCCP, FAASM
As sleep physicians continue to explore the relationship between the brain, sleep, and overall health, some experts express skepticism about linking sleep aids directly to dementia risk.
“For clinical neurologists like me, it is challenging to agree that a sleeping medication will cause dementia, and I would reassure my patients the benefits or a good night's sleep outweigh any claimed potential risk these can cause memory loss as you age or dementia,” – Segil
“Clinical neurologists like me are not concerned [that] using zolpidem appropriately in elderly patients who can’t sleep will cause dementia.” – Segil
There is a call for more comprehensive research to evaluate the impact of sleep aids on human glymphatic flow.
“If more work were to be done in this area, we certainly would like to see if studies could assess the impact of sleep aids on human glymphatic flow,” – Peter G. Polos, MD, PhD, FCCP, FAASM
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