A new study reveals that simple body movements may help clean the brain.
Scientists have found that the brain is more physically linked to the body than once believed. Reporting in Nature Neuroscience, a research team used mice and computer models to uncover a possible explanation for why physical activity benefits brain health.
Their findings suggest that when abdominal muscles tighten, they squeeze blood vessels connected to the spinal cord and brain. This pressure causes the brain to shift slightly inside the skull. That small motion appears to help cerebrospinal fluid move across the brain, which may carry away waste that can interfere with normal brain function.
How Abdominal Contractions Influence Brain Motion
Patrick Drew, professor of engineering science and mechanics, of neurosurgery, of biology and of biomedical engineering at Penn State, said the study builds on earlier research showing that sleep and neuron loss can affect how cerebrospinal fluid moves through the brain.
“Our research explains how just moving around might serve as an important physiological mechanism promoting brain health,” said Drew, corresponding author on the paper. “In this study, we found that when the abdominal muscles contract, they push blood from the abdomen into the spinal cord, just like in a hydraulic system, applying pressure to the brain and making it move. 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.”
Drew, who also serves as associate director of the Huck Institutes of the Life Sciences, compared the process to a hydraulic system in which pressure drives fluid movement. In this case, the “pump” is the abdominal contraction. Even mild tightening, such as bracing before standing up or taking a step, can create this effect. The pressure is transmitted through the vertebral venous plexus, a network of veins connecting the abdominal and spinal cavities, which results in subtle brain movement.
Imaging Shows Brain Shifts During Movement
To observe this process, the team studied mice in motion using two advanced imaging methods. Two-photon microscopy provided detailed views of living tissue, while microcomputed tomography enabled high-resolution 3D imaging of entire organs.
The researchers saw the brain shift just before the animals moved, immediately after the abdominal muscles tightened to initiate motion.
To confirm that abdominal contractions were responsible, the team applied controlled pressure to the abdomens of lightly anesthetized mice. No other movement was involved. The level of pressure was lower than what a person experiences during a blood pressure measurement, yet it still caused the brain to move.
“Importantly, the brain began moving back to its baseline position immediately upon relief of the abdominal pressure,” Drew said. “This suggests that abdominal pressure can rapidly and significantly alter the position of the brain within the skull.”
Simulations Reveal Fluid Flow Through the Brain
After establishing the link between abdominal contractions and brain motion, the researchers investigated how this movement affects fluid flow. At the time, no imaging methods could fully capture the fast and complex behavior of cerebrospinal fluid.
“Luckily, our interdisciplinary team at Penn State was able to develop these techniques, including conducting the imaging experiments of living mice and creating computer simulations of fluid motion,” Drew said. “That combination of expertise is so important for understanding these types of complicated systems and how they impact health.”
Francesco Costanzo, professor of engineering science and mechanics, of biomedical engineering, of mechanical engineering and of mathematics, led the modeling work.
“Modeling fluid flow in and around the brain offers unique challenges because there are simultaneous, independent movements, as well as time-dependent, coupled movements. Accounting for all of them requires accounting for the special physics that happens every time a fluid particle crosses one of the many membranes in the brain,” Costanzo said. “So, we simplified it. The brain has a structure similar to a sponge, in the sense that you have a soft skeleton and fluid can move through it.”
By treating the brain like a sponge, the researchers could simulate how fluid travels through spaces of different sizes, similar to folds in the brain or pores in 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?” Costanzo asked. “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.”
What This Means for Brain Health
Drew noted that more research is needed to understand how these findings apply to humans. However, the results suggest that ordinary movement may help circulate cerebrospinal fluid through the brain, removing waste and potentially reducing the risk of neurodegenerative disorders linked to waste buildup.
“This kind of motion is so small. It’s what’s generated when you walk or just contract your abdominal muscles, which you do when you engage in any physical behavior. It could make such a difference for your brain health,” Drew said.
Reference: “Brain motion is driven by mechanical coupling with the abdomen” by C. Spencer Garborg, Beatrice Ghitti, Qingguang Zhang, Joseph M. Ricotta, Noah Frank, Sara J. Mueller, Denver I. Greenawalt, Kevin L. Turner, Ravi T. Kedarasetti, Marceline Mostafa, Hyunseok Lee, Francesco Costanzo and Patrick J. Drew, 27 April 2026, Nature Neuroscience.
DOI: 10.1038/s41593-026-02279-z
Co-authors include C. Spencer Garborg, postdoctoral researcher in Drew’s lab; Beatrice Ghitti, who was a postdoctoral researcher supervised by both Costanzo and Drew at the time of the research and is now a research fellow at the University of Auckland; Qingguang Zhang, who was an assistant research professor in Drew’s lab and is now an assistant professor of physiology at Michigan State University; Joseph M. Ricotta, who was a postdoctoral researcher in Drew’s lab; Noah Frank, who earned his bachelor’s degree in mechanical engineering from Penn State; Sara J. Mueller, who led the Penn State Center for Quantitative Imaging at the time of the research and is now executive director of the Wildlife Leadership Academy; Denver L. Greenawalt and Hyunseok Lee, graduate students at Penn State; Kevin L. Turner and Ravi T. Kedarasetti, who earned their doctorates from Penn State under co-supervision by Drew and Costanzo; and Marceline Mostafa, an undergraduate student who earned a degree in biology. Microcomputed tomography imaging for this project was performed at the Penn State Center for Quantitative Imaging, an Institute of the Energy and the Environment core research facility.
The National Institutes of Health, the Pennsylvania Department of Health and the American Heart Association supported this research.
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