Does sleep matter?
I know many people who struggle with insomnia, so I often feel uncomfortable talking about sleep and its risk for dementia.
And when you do struggle with sleep, getting enough can seem hopeless.
The research regarding sleep and brain health is advancing, and so is help for people with sleeplessness.
Sleep is Becoming a Pillar of Brain Health
Sleep has been treated as a nice-to-have, something you caught up on over the weekend if you were lucky. This is changing.
The latest research tells us that sleep is an active, nightly maintenance process for the brain, and what happens (or doesn't happen) while we sleep may be one of the most important levers we have for reducing dementia risk.
How sleep protects the brain
The clearest explanation came in 2013, when a University of Rochester lab published a study in Science describing what they called the glymphatic system: a network that flushes waste, including amyloid beta, the sticky protein associated with Alzheimer's disease, out of the brain.
During deep non-REM sleep, brain cells shrink and the space between them expands by roughly 60%, allowing cerebrospinal fluid to move through and carry away metabolic debris.
A 2019 follow-up study by MIT researchers found that during deep sleep, slow waves of brain activity coincide with pulses of cerebrospinal fluid flowing through the brain, helping to clear away waste roughly every 20 seconds.
Deep sleep then is when the brain runs its own cleaning cycle, and that cycle depends on getting enough of deep sleep, not just any sleep.
Why poor sleep is linked to dementia
A 2018 study out of the National Institutes of Health, published in PNAS, scanned 20 healthy adults using PET imaging and found that a single night of total sleep deprivation was enough to measurably increase amyloid beta accumulation in the hippocampus and thalamus, two regions closely tied to memory and to Alzheimer's disease.
A UK cohort study that followed nearly 8,000 civil servants for 25 years, published in Nature Communications in 2021, found that people who consistently slept six hours or less per night in their 50s and 60s had a 30% higher risk of developing dementia later in life, even after accounting for cardiovascular, mental health, and lifestyle factors.
Although an association, not proof of direct cause, the two studies make a compelling case that sleep deserves to sit alongside diet and exercise as a genuine pillar of brain health.
Why we're sleeping worse than we used to
Our sleep has gotten worse. Researchers estimate Americans were sleeping roughly two hours less a night by the end of the 20th century than they were at its start, and current National Sleep Foundation polling suggests more than a third of adults are still getting less than seven hours.
A lot of this comes down to light. Electric lighting, and now the blue-enriched light from our phones and screens, suppresses melatonin and delays the body's natural signal that it's time to wind down.
What we can actually do about it
A few changes tend to matter more than the rest:
Keep a consistent wake time, even on weekends. Although consistent bed times are important, your circadian rhythm responds far more to when you get up than to when you go to bed.
Dim screens and bright lights in the hour before bed. Evening light is the strongest disruptor of melatonin production of this list.
Keep the bedroom cool (18oC/65oF) and dark (darker the better). Temperature drop is part of what triggers the deep, slow-wave sleep the glymphatic system depends on. Wear a sleep mask if you cannot achieve a dark room.
If you snore heavily or wake up gasping (or with headaches), ask your doctor about sleep apnea and request a sleep study. Not only does sleep apnea directly interfere with the deep sleep stages tied to brain clearance, it can deprive your brain of oxygen.
An update from my practice: Aphasia
Cognitive stimulation therapy — physio for the brain.
For clients presenting with aphasia-type word-finding or sentence-formulation difficulty, one of the more encouraging patterns I observe as a client’s CST program progresses is a measurable increase in length and completeness of someone’s response to my questions.
I've used a metric called mean length of utterance (MLU) — the average number of words per spoken response — as a quantifiable marker of this improvement in speech. I'm now looking into speech-analysis tools to begin to track MLU more systematically, with the aim of piloting this in sessions soon.
These gains matter clinically because they reflect increased capacity for communication, self-expression, and most importantly, confidence.
As I continue refining how session outcomes are measured, I hope to eventually quantify these changes numerically, and present them to families after completion of their loved one’s program.
If you have a parent or spouse who could benefit from cognitive stimulation, we'd love to talk. Reply to this email to book a short call. Learn more about the program on our website www.forbetterminds.com
Paws for Thought
Although it’s possible for cats to experience insomnia, our Director of Relaxation appears to be able to sleep anywhere, at any time.
In our next issue, we’ll discover that even the most relaxed among us need something else to thrive: a little company.
