by Carrie Heeter, spring 2018
The system of yoga and meditation that I study and practice uses attention to breath and conscious breath control to change the state of the system and focus the mind. A high speed MRI study revealed one of the powerful ways breath affects the brain.
Cerebralspinal fluid (CSF) carries immune cells throughout the brain and removes waste and toxins.
When CSF flow is impeded, the brain can become suffused with inflammatory immune cells. This process may play a key role in traumatic brain injury, auto-immune diseases like multiple sclerosis and neurodegenerative illnesses such as Alzheimer’s disease and Parkinson’s disease.
CSF flow, long believed to be influenced by heart beat, has been shown to be much more heavily impacted by breath.
Specifically, CSF flow increases during inhale and slows during exhale.
For all subjects in this high-speed MRI study, “inspiration was the dominant influence of CSF flow.” Some individuals have a stronger heart rate influence on CSF flow than others. But for everyone, breath was the dominant influence on CSF flow.
The researchers examined three breath patterns: 1) “normal breathing”,” 2) “forced inhale” 2.5 second inhalation, 2.5 second exhalation and 3) “breath holding” 12 second breath holding (my guess is that breath was held after inhale).
They also conclude “breath holding entirely suppressed the respiratory-related component” of CSF flow. In the figure below, the top graph is person 1, the middle graph person 5 and the bottom graph person 9. The black bars indicate the 12 second period of breath holding. The graph shows CSF flow rate.
I am not a neuroscientists, but as a student of meditation and yoga i have worked with and studied breath (including inhalation, exhalation, holds after inhale, holds after exhale, and exquisite variations on breath ratios) for many years. When I read the study and look at the the data (such as the figure below), it seems there is much more to be explored if we combine these high speed MRI techniques, neuroscience expertise, and yoga expertise.
High speed MRI of CSF flow during 12 second breath hold
Dreha-Kulaczewski, S., Joseph, A. A., Merboldt, K.-D., Ludwig, H.-C., Gärtner, J., & Frahm, J. (2015). Inspiration Is the Major Regulator of Human CSF Flow. Journal of Neuroscience, 35(6), 2485–2491. https://doi.org/10.1523/