Hi Reader
Dad Joke:
The brain and the gut are connected!! Yes…I agree...cool…tell me something else from the 1990’s. The vagus, the microbiome, immune signalling, visceral sensation and autonomic regulation all contribute to a bidirectional connection between the gut and the brain…but we know that already.
It’s so mainstream that even the Rome V, rather than treating persistent gut symptoms as simply “functional” now recognises that symptoms may emerge from changes across motility, visceral sensitivity, the intestinal environment and the way signals are processed by the brain. Welcome to the Disorders of Gut–Brain Interaction framework! (who is stuck in the 90’s now!)
BUT…
What if it the link isn’t just neural and chemical…what if it is also mechanical?
Leave your bucket hats and high waisted mom jeans in the nostalgia bay and take a look at this 2026 study in Nature Neuroscience that suggests that abdominal pressure may influence movement of the brain and possibly the movement of fluid within and around it.
You read that right!
But before we go too overboard…the research was conducted in mice. It doesn’t prove that core exercise clears the brain or treats neurological or gastrointestinal conditions. But it does identify a biologically plausible mechanical pathway worth exploring.
Come join me down the rabbit hole…we have carrots!
The brain moves slightly within the skull (again…not news to us). In anaesthetised animals and supine humans, this has been linked to breathing and cardiac pulsation. But in awake mice, the researchers found something different.
Using high-speed microscopy, they noticed that the brain moved forwards and laterally during locomotion. This movement was closely associated with running, but not with breathing or the cardiac cycle. Importantly, the brain often began moving before the animal started to run. (if you have done Paeds in Motion Seminars you will know all about anticipatory postural control)
The abdominal muscles appeared to provide the link.
Abdominal muscle activity consistently preceded brain movement. As the core activated in preparation for movement, the brain shifted. When the abdominal muscles relaxed, it returned towards its starting position…pretty wild stuff huh!
This fits with anticipatory postural control. Before movement begins, the trunk prepares. Abdominal contraction raises intra-abdominal pressure and creates a stable platform from which the limbs can move.
Core stabilisation is therefore not simply about holding the body still. It is a dynamic pressure-management strategy and that pressure may influence more than the trunk.
The pathway involves the vertebral venous plexus, a network of largely valveless veins connecting the abdominal circulation with vessels inside the spinal canal. When the abdominal muscles contract, intra-abdominal pressure rises. This may shift blood into the vertebral venous system, increasing pressure around the dural sac. Cerebrospinal fluid may then be displaced upwards, increasing intracranial pressure and moving the brain slightly within the skull. Say that 10 times fast.
For those (like me) who need to write it down on the back of a napkin:
The abdominal wall contracts. Pressure enters the spinal system. Fluid shifts cranially. The brain moves.
The researchers used computer modelling to explore what this movement might do to fluid. The model suggested that compression of the spinal compartment and movement of the brain could help shift interstitial fluid outwards towards the subarachnoid space.
So…
Sleep may support fluid movement into and through brain tissue. Movement may contribute to a different phase of the cycle by helping move fluid outwards.
That’s the hypothesis from the modelling, not a confirmed human mechanism.
But…it raises the possibility that fluid dynamics around the brain may depend not only on sleep, respiration and arterial pulsation and primary rhythms, but also on body movement and trunk-generated pressure.
Clinically, this gives us another reason to stop thinking of “the core” as a just six-pack.
Abs are important…But a nourished and cleansed out brain is importanter
Chat soon
Mike
Link to paper: https://www.nature.com/articles/s41593-026-02279-z
