Study links physical movement with brain's cleansing process
Your brain has its own built-in cleaning system-and it works better when you move.
A study suggests that simple physical actions can set cerebrospinal fluid in motion. This clear liquid flows through the brain, helping wash away waste that could otherwise interfere with how you think and function.
But that's not all it does. Cerebrospinal fluid also acts like a shock absorber, protecting your brain and spinal cord, while delivering essential nutrients. As part of the glymphatic system, it plays a key role in keeping your brain fresh, clear, and running smoothly.
"Our research shows that even simple movement may play an important role in keeping the brain healthy," said Patrick Drew, a professor of engineering science and mechanics, neurosurgery, biology, and biomedical engineering at The Pennsylvania State University in the US.
He explained that in their study on mice, when abdominal muscles contract, they push blood from the abdomen toward the spinal cord-almost like a hydraulic system. This creates pressure that gently moves the brain, helping to circulate fluids inside it.
"Simulations show that this gentle brain movement will drive fluid flow in and around the brain. It is thought the movement of fluid in the brain is important for removing waste and preventing neurodegenerative disorders. Our research shows that a little bit of motion is good, and it could be another reason why exercise is good for our brain health," the corresponding author of the study published in the journal Nature Neuroscience said.
The researchers said even small actions, such as bracing your core before standing up or taking a step, can create the 'pumping' effect.
Movement matters
Research from October 2025, published in the journal 'Alzheimer's and Dementia: The Journal of the Alzheimer's Association', suggested that problems with the brain's waste clearance due to an impaired movement of the cerebrospinal fluid could contribute towards developing dementia, a neurodegenerative disorder.
The team observed moving mice and found that the brain shifted just before the animals moved, immediately after the abdominal muscles tightened to initiate motion.
Further, they applied a gentle, controlled pressure to the abdomens of lightly anaesthetised mice.
The level of pressure was lower than what a person experiences during a blood pressure test, yet it still caused the brain to move, the researchers said.
"Importantly, the brain began moving back to its baseline position immediately upon relief of the abdominal pressure. This suggests that abdominal pressure can rapidly and significantly alter the position of the brain within the skull," Drew said.
The 'sponge' experiment
To understand how the brain's movement influences the flow of the cerebrospinal fluid, the team created computer simulations of fluid motion. They also developed imaging techniques for conducting experiments with live mice.
The researchers treated the brain like a sponge and simulated how fluid travels through spaces of different sizes, similar to the folds of the brain or the pores of a sponge.
"Keeping with the idea of the brain as a sponge, we also thought of it as a dirty sponge - how do you clean a dirty sponge?" Francesco Costanzo, professor of engineering science and mechanics at The Pennsylvania State University, said.
"You run it under a tap and squeeze it out. In our simulations, we were able to get a sense of how the brain moving from an abdominal contraction can help induce fluid flow over the brain to help clear waste products," Costanzo said.
No more waste
Patrick Drew, a professor of engineering science and mechanics, neurosurgery, biology, and biomedical engineering at The Pennsylvania State University in the US, noted that more research is needed to determine how the study's findings apply to humans.
However, the results suggest that everyday movement may help circulate cerebrospinal fluid through the brain, aiding in the removal of waste and possibly lowering the risk of neurodegenerative diseases linked to waste buildup, Drew said.