- A new study suggests yawning may play a crucial role in regulating cerebrospinal fluid flow in the brain, challenging previous theories about oxygen regulation or signalling tiredness.
- Using MRI scans on 22 healthy participants, researchers found that yawning reorganises the outflow of CSF, which is vital for removing waste, transporting chemicals, and maintaining brain health.
- The study observed that yawning significantly increased CSF flow compared to normal or deep breathing, indicating that it had a “functional physiological purpose” and wasn’t just a social cue to indicate tiredness.
- Researchers noted that yawning involves consistent, involuntary muscle movements controlled by the brainstem, and even stifled yawns maintain nearly the same duration as uninhibited ones, meaning that stifling did not affect the underlying process.
- These findings imply that yawning may also influence solute transport and brain cooling, potentially offering new insights into conditions like migraine, which are linked to impaired CSF flow.
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