The Power of The Exhale
Exhaling has its benefits. As does Breath holds.
Before you go further in this article …. take a deep breath in, hold briefly, and slowly exhale for a about 8 seconds.
That exhale was medicine for your body.
I will explain further.
In those 8 seconds you just released Vagusstoff. This a substance that Otto Loewi in 1921 described is released by the Vagus Nerve during exhalation . It was eventually determined that this substance was acetylcholine.
The release of acetylcholine has many effects:
One profound effect is the impact acetylcholine has on the cardio-regulatory systems and heart rate variability (HRV). Studies have shown that acetylcholine release by the Vagus Nerve enhances HRV by rebalancing autonomic activity, leading to improved baroreflex sensitivity and cardiac vagal control. (Sunagawa, 1998) Basically it helps regulate our heart beat and probably our blood pressure as well.
Also acetylcholine is highly involved in regulating our immune system:
Acetylcholine has been known to reduce proinflammatory signals (a.ka. cytokines) from immune cells (Casado-Bedmar, M. and Keita, Å. ,2020). This is this through the cholinergic anti-inflammatory pathway (CAP) is referred to as the neuroinflammatory reflex. (Ruzafa, L., Cedillo, J., & Hone, A. ,2021). It appears that the acetylcholine binds to α7 nicotinic acetylcholine receptor (α7nAChR) in resident tissue macrophages and reduces their inflammatory activity. (Matsumoto, N.,et.al, 2013)
So how does this work:
Vagal nerve stimulation (which can happen many ways) increases norepinephrine which triggers the release of acetylcholine from spleen and that spleen lymphocytes. (Rosas-Ballina, M, 2011). In rats it has been shown that upon activation of this cholinergic anti-inflammatory pathway (CAP) the nerve endings of the vagal nerve efferents release acetylcholine. (Seesing, M, 2023)
So what about exhaling?
It’s probably not so much about exhaling that has the effects but rather the breath holding that was done before exhaling.
Let me try to explain.
When the breath is held, carbon dioxide can't leave the body via the lungs. Instead, it builds up in the blood (a.k.a. hypercapnia). If exhalation follows a period of hypercapnia; there is reported to be an amplified cardio-inhibitory effect of exhalation via the vagus nerve (Singh, U. ,2017). So if I am holding my breath (in a breathing practice) or more practically when I am stressed then I am experiencing micro moments of hypercapnia; and an exhale following the breath-hold may have profound effects.
Hypercapnia is an epidemic in my experience. Just sit in a cafe and watch people type on their keyboard or look at their phone….its amazing we are still alive…no one is breathing!!! I exaggerate of course. But compared to what is normal rhythmic breathing most people are stuck in a breath hold for quite some time and doing shallow breathing.
It appears to me that vagal nerve stimulation creates more of dynamic response that you would expect from a positive stressor. It is not so much a direct “chill pill”, but likely a nudge in the bodies resilience pathways. Where a stress to the system causes the organism to adapt and then release effects that improve strength, resiliency, and homeostasis.
When my IBS was really bad 20 or so years ago and before I knew I had celiac disease; I would be taking a test in medical school and my stomach would make gas sounds that were a combination of of a tambourine and a base drum.
It was embarrassing at the time as I was somewhat less accepting of my body sounds and rhythm; I found that if I would focus on belly breathing and exhaling the gut would calm down. Now admittingly in the midst of a test that was not always easy to do; and I was insecure that my fellow colleagues thought I was test taking and farting simultaneously. While the Adam of today is much more accepting of body sounds; that version was quite insecure with it.
Thankfully after much work on my gut an discovery; I have much more balance in this arena. It’s amazing to look back that I was really providing acetylcholine for my gut and helping the inflammation calm down, and likely impacting blood flow to my intestines.
Dr. Geoff Lecovin in my upcoming podcast talks about how breathwork creates your own medicine. After understanding the vagal release of acetylcholine ,we can see how we can create our own medicine!
If you are interested in diving into vagal nerve things please check out my Sound Safe Protocol offerings
References:
Sunagawa, K., Kawada, T., & Nakahara, T. (1998). Dynamic nonlinear vago-sympathetic interaction in regulating heart rate. Heart and Vessels, 13(4), 157-174. https://doi.org/10.1007/bf01745040
Casado-Bedmar, M. and Keita, Å. (2020). Potential neuro-immune therapeutic targets in irritable bowel syndrome. Therapeutic Advances in Gastroenterology, 13, 175628482091063. https://doi.org/10.1177/1756284820910630
Ruzafa, L., Cedillo, J., & Hone, A. (2021). Nicotinic acetylcholine receptor involvement in inflammatory bowel disease and interactions with gut microbiota. International Journal of Environmental Research and Public Health, 18(3), 1189. https://doi.org/10.3390/ijerph18031189
Matsumoto, N., Imamura, Y., Muroya, T., Yamada, T., Nakagawa, J., Shimazaki, J., … & Shimazu, T. (2013). Electrical vagus nerve stimulation attenuates systemic inflammation and improves survival in a rat heatstroke model. Plos One, 8(2), e56728. https://doi.org/10.1371/journal.pone.0056728
Rosas-Ballina, M., Olofsson, P., Ochani, M., Valdés‐Ferrer, S., Levine, Y., Reardon, C., … & Tracey, K. (2011). Acetylcholine-synthesizing t cells relay neural signals in a vagus nerve circuit. Science, 334(6052), 98-101. https://doi.org/10.1126/science.1209985
Seesing, M., Janssen, H., Geraedts, T., Weijs, T., Ark, I., Leusink-Muis, T., … & Luyer, M. (2023). Exploring the modulatory effect of high-fat nutrition on lipopolysaccharide-induced acute lung injury in vagotomized rats and the role of the vagus nerve. Nutrients, 15(10), 2327. https://doi.org/10.3390/nu15102327
Singh, U. (2017). Evidence-based role of hypercapnia and exhalation phase in vagus nerve stimulation: insights into hypercapnic yoga breathing exercises. Journal of Yoga &Amp; Physical Therapy, 07(03). https://doi.org/10.4172/2157-7595.1000276