The two Scientific American articles (see below) explain why sleep is essential for a healthy body, mind & soul. It’s quite rare to me that I compromise with my sleep. When I do, I will be forced to pay a price / penalty for the next few days.
In my past, I used my weekends – and also my vacation – to recover from sleep deprivation. Nowadays, I use one – or even several – power naps to recover from a sudden, eating or writing, fatigue.
My body needs a 7-8 hour sleep cycle because my mind is nearly always in overdrive. I cleanse my soul by praying, just before finding my sleep. It’s rare not finding my sleep. Late and difficult conversations are an obstacle though. I tend to avoid those. The airplane mode on my mobile phone helps a lot.
“The phrase [Mens sana in corpore sano] comes from Satire X (c. 2nd century AD) of the Roman poet Juvenal (10.356). It is the first in a list of what is desirable in life:”
“You should pray for a healthy mind in a healthy body.
Ask for a stout heart that has no fear of death,
and deems length of days the least of Nature’s gifts
that can endure any kind of toil,
that knows neither wrath nor desire and thinks
the woes and hard labors of Hercules better than
the loves and banquets and downy cushions of Sardanapalus.
What I commend to you, you can give to yourself;
For assuredly, the only road to a life of peace is virtue.”Note LO: translation from original Latin text
Cleanse My Soul (2013) by Maria Roe Vincent
artist, no lyrics, video, Wiki-artist
Take away these tears
I pray, please take away my fears
I long to see what you promised me
The assurance of your peace
Note: all markings (bold, italic, underlining) by LO unless in quotes or stated otherwise.
Scientific American, Mind & Brain: How Your Brain’s Nightly Cleanse Keeps It Healthy
SA subtitle: Washing waste from the brain is an essential function of sleep—and it could help ward off dementia
By: Allison Parshall, Associate Editor, Mind & Brain
Date: 20 August 2025
“Your brain generates tons of waste—if it builds up, it can become toxic. But as little as 15 years ago, scientists had no idea where all that waste went. The brain is protected by the blood-brain barrier, which is supposed to stop almost almost everything from passing through.
The answer is a whole new body system that scientists have only recently discovered. It’s called the “glymphatic” system, and it bathes the brain in cerebrospinal fluid to clear out toxic proteins and molecules.
What’s more, this might even be why we sleep. Researchers have found that the brain’s “wash cycle” is most active during deep sleep, when slow waves of electrical activity pulse across the brain. This helps explain why sleep deprivation can be so dangerous—and why it has been pegged as a risk factor for Alzheimer’s disease. It’s possible that poor functioning of the glymphatic system could explain why aging brains accumulate the tangled proteins and plaques that are associated with Alzheimer’s disease.
But there’s also reason for hope. If we can understand common ways that the glymphatic system goes wrong, we can target it with treatments. Glymphatic impairment could one day be like hypertension: a risk factor for doctors to monitor and treat.
This is just one example of an entire scientific field, which once treated the glymphatic system as “heresy,” changing its mind. These stories cut to the heart of what it means to do science—following observations and evidence rather than dogma.”
Scientific American, Today in Science: Brain Washing
By: Andrea Gawrylewski, Chief Newsletter Editor
Date: 20 August 2025
“While awake, the human brain generates waste—excess proteins and other molecules that can be toxic if not removed. Those include the proteins amyloid beta and tau, which are key drivers of Alzheimer’s disease. Scientists have found that electrical waves that sweep through the brain during sleep and store memories, seem to also propel cerebrospinal fluid (CSF) in and out of the brain, clearing away toxins.
What they found: Building on previous mouse studies, researchers injected a tracer into the cerebral spinal fluid of human participants. One group slept normally through the night; the other was kept awake for 24 hours. All participants underwent multiple MRI scans in the evening and again the next day. Participants who had not slept had dramatically more amounts of the tracer in their CSF, meaning it hadn’t been cleared from the brain.
How it works: Sleep occurs in four stages, each characterized by a distinct pattern of electrical activity. Each full cycle of a sleep stage lasts for about 90 minutes. During stage 2 and 3 sleep, large waves of electrical activity sweep across the brain, helping to integrate memories. These waves also pulse blood and CSF within the arterioles. The CSF enters astrocyte cells through channels in their end feet and exits these cells into the gray matter of the brain. After sweeping up debris, the CSF reenters a perivascular cavity (donut-shaped spaces surrounding blood vessels), this time one surrounding a venule, or small vein. The CSF and its waste travel alongside the venule to the periphery of the brain and, ultimately, leave it.
Note LO: see article for image re “Clearing the Brain”
Why this matters: If clearing out waste from the brain is an essential purpose of human sleep, then a dysfunction in this system probably relates to many neurological and psychiatric disorders, including Alzheimer’s. How well this brain-cleaning system functions may someday be like hypertension, something to be treated before it turns into a more serious condition.”
Sources:
- Scientific American, Mind & Brain, 20 August 2025, How sleep cleans your brain
- Scientific American, Today in Science, 20 August 2025, Sleep cleans the brain and keeps you healthy
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