A new study from Penn State University reveals that physical movement triggers a hydraulic pump that flushes waste fluid from the brain.
Researchers discovered that abdominal muscle contractions push blood from the abdomen into the spinal cord, creating pressure that shifts the brain and clears cerebrospinal fluid.
"Just moving around might serve as an important physiological mechanism promoting brain health," says neuroscientist Patrick Drew.
In experiments with mice, scientists observed brain movement immediately after abdominal contractions. Applying light pressure to the abdomens of anesthetized mice confirmed the source.
The brain returned to baseline as soon as pressure was released, suggesting the mechanism is rapid and reversible.
Micro-CT scans revealed the network of veins connecting the abdominal cavity, spinal cord, and brain. Computer modeling showed that subtle brain movements from abdominal tensing are enough to push cerebrospinal fluid through the brain into the subarachnoid space.
This flow is critical for removing waste products linked to neurodegeneration. The finding may explain why cerebrospinal fluid flows differently during sleep versus waking hours.
"This kind of motion is so small. It's generated when you walk or contract your abdominal muscles. It could make such a difference for your brain health," Drew says.