Dementia Risk Factors and the Role of Sleep
Staying on top of the health and lifestyle factors associated with dementia is becoming a Sisyphean battle. In recent years, advances in research have allowed scientists to identify many different aspects of our lives associated with dementia risk. Some of those are relatively easy to modify, such as brain training, diet, and exercise. Others are a lot harder to control – and a lot harder to link to a simple behavioral change. Chronic stress, aging, cardiovascular disease, and depression have all individually been linked to a higher dementia risk. A new review of published studies suggests they may be connected by a shared thread.
Sleep as the Common Denominator
The common denominator of all these factors, it concludes, is sleep. More specifically, the role sleep may play in helping the brain clear the metabolic waste that accumulates during the waking hours. “Many disorders that increase dementia risk also disrupt the brain’s sleep rhythms,” says neuroscientist Maiken Nedergaard of the University of Rochester in the US. “Our work suggests these may not be separate phenomena. They may be connected through the brain’s ability to clear waste during sleep.”
The Glymphatic System Discovery
Sleep is one of the big mysteries of animal biology. When sleep is poor, insufficient, or disrupted, a whole host of things will start going wrong. Over a decade ago, in 2012, Nedergaard’s lab made a discovery that transformed neuroscience: the glymphatic system and its functions. First identified in mice, and later in humans, this paravascular network is thought to help circulate cerebrospinal fluid through the brain. It may play an important role in removing metabolic waste products. Some scientists have also proposed that the glymphatic system may help flush out proteins associated with Alzheimer’s and Parkinson’s diseases.
Sleep Quality and Brain Cleansing
Some studies suggest that the glymphatic system is more active during sleep, although one notable 2024 study in mice found the opposite to be true. Nedergaard’s review suggests that the picture may be more complicated, and that the quality of sleep is integral to glymphatic function. “Sleep is not a quiet or inactive state,” Nedergaard says. This perspective shifts the focus from simply getting enough sleep to ensuring that sleep is restorative and uninterrupted.
For individuals looking to reduce their dementia risk, prioritizing sleep hygiene may be a practical step. While the review does not offer specific recommendations, experts often advise maintaining a consistent sleep schedule, creating a dark and quiet bedroom environment, and avoiding stimulants before bedtime. As always, consult a healthcare professional before making significant changes to your sleep habits or addressing underlying conditions like depression or cardiovascular disease.
Frequently Asked Questions
What bodily function may link many dementia risk factors according to a new review?
A new review suggests that sleep is the common denominator linking dementia risk factors such as chronic stress, aging, cardiovascular disease, and depression, specifically through the brain’s ability to clear waste during sleep.
What is the glymphatic system and how might it relate to dementia?
The glymphatic system is a paravascular network that circulates cerebrospinal fluid through the brain and helps remove metabolic waste, including proteins associated with Alzheimer’s and Parkinson’s diseases. It may be more active during sleep, and its function is integral to sleep quality.
What did Maiken Nedergaard’s lab discover in 2012 that transformed neuroscience?
In 2012, Nedergaard’s lab discovered the glymphatic system and its functions, first identified in mice and later in humans, which is thought to help clear metabolic waste from the brain during sleep.
