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It's a fact of life: Our cells produce waste, which the body needs to remove to stay healthy.
This is especially important in the brain, which has a specialized plumbing system — called the glymphatic system — to flush out the metabolic garbage.
A cleaner brain may be a healthier brain. If the brain's plumbing doesn't work properly, research shows, cellular waste accumulates, including proteins implicated in neurodegenerative and psychiatric diseases.
The glymphatic system's function declines "exponentially" with age, said Maiken Nedergaard, a professor at the University of Copenhagen and the University of Rochester, who discovered the system in 2012. And it can get gummed up by low — grade inflammation and stymied by poor cardiovascular health, which contributes to poor brain health.
But there are steps you can take to better care for your brain's plumbing.
Here's what to know about the glymphatic system, plus three science-backed ways you can improve its function and your overall brain health.
The brain's plumbing system
The lymphatic system clears out waste from your body's tissues, using muscles to help pump fluid around your body. But when it comes to the brain, things work a bit differently.
The glymphatic system is a vast network of tiny spaces around the brain's blood vessels. As your heart pumps, the blood vessels expand and contract, which moves the surrounding cerebrospinal fluid through those spaces. This fluid mixes with other fluid that is between brain cells. Then it drains out, carrying waste.
There's still a lot we don't understand about the system. But mounting evidence shows it may play a role in many brain diseases and could be a viable target for new treatments. Studies show that patients with neurological disorders, including Alzheimer's, Parkinson's disease and stroke, may have reduced glymphatic function.
In mouse models, disrupting the glymphatic system resulted in more garbage accumulation and aggravated progression of Alzheimer's and Parkinson's. This can create a vicious cycle of waste accumulation, triggering inflammation that aggravates glymphatic dysfunction.
Sleep
Sleep is when the brain does most of its cleaning.
In an influential 2013 paper published in Science, Nedergaard and her colleagues found that sleep increased the removal of metabolic waste and amyloid beta protein, which forms sticky plaques in those with Alzheimer's disease, from the brain. Subsequent research has replicated this finding.
On the other hand, sleep deprivation slows down the flow of fluid and accelerates the buildup of cellular garbage.
Cleaning is strongest during non — rapid eye movement (non — REM) sleep, when there are very slow oscillations of brain, blood and neurochemical activity. The brain's blood vessels ebb and flow every 10 to 50 seconds, dramatically increasing the volume of the arteries by 10 percent, which in turn moves fluid through the glymphatic system.
There is some early research on how REM sleep affects glymphatic function, suggesting that "non — REM would fill the toilet up and REM sleep would flush it," said Lauren Hablitz, an assistant professor of neurology at the University of Rochester Medical Center who worked with Nedergaard.
Good sleep hygiene helps keep our brain clean. These steps can help:
• Keep your sleep schedule consistent. "A lot of times the shift between a weekend and a workweek is really hard on the body," Hablitz said.
• The bed is for sleep. If you can't sleep, instead of scrolling on your phone, get up for a bit and return when your body is ready to sleep.
• Try to get sleep the natural way, if you can. "Taking sleep medication is not good because that inhibits these oscillations," Nedergaard said.
• Don't overstress about sleep. Most neurodegenerative diseases have been linked to poor sleep, but "it is a very long — term process, so one shouldn't worry about one bad night of sleep," Nedergaard said.
Exercise
When you're exercising, your glymphatic system actually slows down. But there is emerging evidence that long — term exercise can improve glymphatic function.
A 2025 study of 37 healthy adults found evidence that 12 weeks of moderate — intensity exercise increased the flow of fluid through the glymphatic system compared with one exercise session.
Because the brain's plumbing system relies on the heart, cardiovascular health is vitally important to glymphatic function, said James Broatch, a senior research fellow at Victoria University's Institute for Health and Sport, who wrote a recent review in Trends in Neurosciences about how exercise affects the glymphatic system. The boost to heart health may be one of the main ways exercise improves glymphatic flow, he said.
In the long term, exercise also decreases inflammation, which in turn can increase glymphatic function. Exercise also promotes better sleep.
• The most important tip about exercise is just doing it. "Any exercise is better than no exercise," Broatch said.
• Be consistent. "The best exercise you can do is something you're going to stick to," Broatch said. Find something social and something you enjoy doing to help reinforce the habit.
• Incorporate exercise into daily life. Park your car farther away or take the stairs instead of the elevator, Broatch said.
• Even a few minutes counts. Research shows getting up and moving even a little bit can have profound health benefits.
Mindful breathing
Breathing exercises can calm the mind, research shows, and many people find mindfulness and breathing practices to be mentally cleansing. There is some early evidence that this may be literally true.
A 2022 study of 18 adults found that different forms of deep and slow breathing could cause large changes in brain fluid movement compared with normal breathing. Deep abdominal breathing had the largest effects.
Breathing regulation techniques can bring about "big changes in how your diaphragm is working" and can pull fluid from your brain, said Hablitz, who was not involved in the breathing studies.
Meditating and yoga help control our autonomic system — whether we are in more of a high — octane "fight — or — flight" or relaxed "rest — and — digest" mode — which probably promotes glymphatic flow, Nedergaard said.
To get started, try different breathing patterns — breathing slowly through your nose, letting your diaphragm fill and rise.
• Box breathing involves equal time spent inhaling, holding, exhaling and holding, with each step lasting three or four seconds.
• Four — seven — eight breathing extends the duration: Breathe in for four seconds, hold for seven and breathe out for eight.
• Cyclic sighing involves inhaling slowly and then inhaling again to fully fill the lungs before slowly exhaling.
• Practices such as yoga and meditation also can slow down the breath.
Richard Sima is a neuroscientist turned science journalist.
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