Chronic sleep deprivation and sleep disorders are associated with many health problems including cardiovascular diseases, diabetes, obesity, anxiety, and depression . A study published this month in Neurology adds Alzheimer's disease to that list .
The study investigated the relationship between sleep quality and Alzheimer's by measuring markers of the disease in spinal fluid. The participants—101 "cognitively normal" people with an average age of 63 and either a family history or genetic risk factor for Alzheimer's—completed a survey on sleep quality and provided spinal fluid samples. Researchers discovered that worse sleep quality, more sleep problems, and daytime sleepiness were associated with altered levels of markers for beta-amyloid?, tau?, and inflammation in the spinal fluid, all of which are involved in Alzheimer's. These associations persisted even after controlling for factors such as race, BMI, education, symptoms of depression, or use of sleep medications.
It is possible that sleep problems promote the development of Alzheimer's, or that the changes Alzheimer's produces in the brain reduces sleep quality, or both, which may create a vicious cycle. For example, a previous study in older adults has shown that beta-amyloid proteins in the brain (which make up Alzheimer's plaques) may interfere with sleep quality and memory formation . And preclinical studies suggest that sleep disturbance can promote the formation of beta-amyloid plaques and reduce the removal of beta-amyloid from the brain. Toxic proteins including beta-amyloid and tau that can eventually form plaques and tangles are "flushed out" of the brain during sleep, so it makes sense that poor sleep would result in higher levels . A recent study in middle-aged adults reported that disrupting just one night of sleep during the deep non-REM phase is enough to cause a change in spinal fluid levels of beta-amyloid .
Though we still have unanswered questions about the role of poor sleep in the development of Alzheimer's, there is already a clinical trial testing the potential of sleep aids to treat Alzheimer's disease .
If you don't get enough sleep or have poor quality sleep, addressing these issues may help lower your risk for Alzheimer's disease. Establish a bedtime routine and maintain a regular sleep schedule. If you suspect you have insomnia or sleep apnea, talk to your healthcare provider about treatment options. (Not all medications improve deep non-REM sleep, and some carry brain health risks.) The Centers for Disease Control and Prevention recommends at least seven hours of sleep per night for adults .
Yuko Hara, PhD, is Acting Director of Aging and Alzheimer's Prevention at the Alzheimer's Drug Discovery Foundation. Dr. Hara was previously an Assistant Professor in Neuroscience at the Icahn School of Medicine at Mount Sinai, where she remains an adjunct faculty member. Her research focused on brain aging, specifically how estrogens and reproductive aging influence the aging brain's synapses and mitochondria. She earned a doctorate in neurology and neuroscience at Weill Graduate School of Medical Sciences of Cornell University and a bachelor's degree in biology from Cornell University, with additional study at Keio University in Japan. Dr. Hara has authored numerous peer-reviewed publications, including articles in PNAS and Journal of Neuroscience.
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