Every year, millions of people visit "the most magical place on Earth," not knowing one of the biggest modern-day engineering marvels on the planet is right under their feet...
Beneath the crowded, bustling streets of Disney's Magic Kingdom lies a massive network of underground tubes. These pneumatic tubes are part of the park's automated vacuum collection ("AVAC") system. (A pneumatic system means it operates entirely on compressed air and powerful, high-speed vacuums.)
Park employees dump bags of trash in the nearly 20 collection points scattered throughout the Magic Kingdom. Every 15 minutes, that trash gets sucked away through the tubes to a central processing location, with speeds clocking in at 60 miles per hour. From there, it's sent to a landfill or a recycling facility.
The Swedish-built technology was the first of its kind in the U.S. but is common in Europe, namely in cities like Barcelona and Stockholm. And for more than 50 years, this system has been helping to keep the Magic Kingdom pristine.
And guess what? Your brain relies on a similar plumbing network, one that's fully automated and highly efficient...
How Your Brain's Sewage System Works
This under-the-skin waste-removal process is called the glymphatic system. Unlike Disney's trash chutes, which run throughout the day, your glymphatic system operates "when the park is closed" – when you're sound asleep.
You see, your brain performs incredible feats of processing every second that require a lot of metabolic processes. Those processes create metabolic byproducts... waste that can build up and harm the brain.
It's not just the metabolic waste from everyday brain processing... Acute trauma – like a stroke – produces a massive influx of inflammatory waste and damaged proteins. Your glymphatic system helps chute the junk away, preventing permanent damage.
In fact, a 2024 review of 67 studies published since 2012 found that when this "washing machine" feature breaks down, the ensuing backup of waste becomes a major driver of cognitive decline and complications from strokes, brain tumors, and traumatic brain injuries.
If you let this kind of garbage accumulate, it can even lead to one of the most feared diseases of old age: Alzheimer's.
An Alzheimer's diagnosis has three characteristics that distinguish it from less severe cases of dementia: memory impairment, plaque (beta-amyloid) buildup in brain tissue, and "tangles" of phosphorylated tau proteins.
But thanks to the glymphatic system, the toxic plaque and tangle proteins get washed away. As to how that "wash" cycle happens...
Rinse and Repeat
It happens largely while you're sound asleep...
Your brain shrinks down its cells to make room for the cerebrospinal fluid ("CSF"). According to a 2013 study, they shrink by about 60%.
CSF is a clear liquid that your brain makes out of your blood. It washes over and through your brain and spinal cord, cushioning them against injury and delivering nutrients.
That CSF mixes with the waste, and the "wastewater" gets whisked away from the brain, through the blood vessels and to the liver.
As for the "washing machine" analogy, it's pretty spot-on...
In a Boston University study that used MRI scans of sleeping participants' brains, researchers found that the CSF came in waves, washing over the brain on a repeated cycle – just like the slow rotation of a washing machine.
Interestingly, the brain sent an electrical signal just before each wave started. This signal pattern matches something we've already seen – the slow brain waves we produce during deep sleep.
Deep Cleaning During Deep Sleep
There are two main stages of sleep – non-REM "deep sleep" and REM "dream sleep." (REM stands for "rapid eye movement.")
Deep sleep happens during the first half of your sleep. This is when your body repairs itself, releasing growth hormones and repair proteins to regenerate muscles. It's also when you start to build memory, as your brain transfers memories from the short-term storage in your hippocampus to the long-term storage in your cortex.
Most important, deep sleep is the restorative cleaning cycle for your brain. And here's the kicker... Folks with Alzheimer's have reduced deep-sleep brain waves.
A 2026 study in Nature Communications shows just how crucial this wash cycle is... Researchers monitored 39 participants overnight, comparing what happens during normal sleep with sleep deprivation.
The team found that getting normal sleep significantly increased the glymphatic system's ability to clear out those Alzheimer's proteins I mentioned earlier. However, when participants were sleep deprived, that impaired their clearance process.
Human and animal studies show that just a single night of sleep deprivation creates problems clearing this waste fluid.
To ensure your brain's wash cycle runs every night, you need to get enough high-quality sleep. That means doing things like...
- Keeping your room cool: This will help ease your body into slumber and reach deep sleep. I recommend having the temperature at around 65 degrees.
- Sticking to the same sleep schedule: Training your body and brain to rest at a certain time will make it easier to fall asleep so you can reach those vital deep-sleep stages.
- Treating obstructive sleep apnea: If you have sleep apnea, you likely snore heavily or stop breathing during the night... both of which will stall that washing-machine action.
- Trying side-sleeping: Believe it or not, research has shown that glymphatic transport and CSF clearance work best when you're sleeping on your side. So give that a try, too.
What We're Reading...
- Something different: Is there a glymphatic connection between eye disease and dementia?
Here's to our health, wealth, and a great retirement,
Dr. David Eifrig and the Health & Wealth Bulletin Research Team
June 4, 2026