I'm sure we are all familiar with that sickening feeling that manifests in our gut when we feel stressed. That saying of feeling 'sick to the stomach' often prefaces a moment of intense stress.
A 2013 study evaluated the effect stress can have on the gut. It took 23 healthy volunteers and submitted them to several conditions believed to cause stress to the body. One of these included public speaking.
Subjects were asked to deliver a 30-45 minute oral presentation in front of an examination jury. They found that public speaking increased the intestinal permeability in healthy volunteers and increased the levels of salivary cortisol (our stress hormone) before and after the exam.
The ongoing production of stress hormones compromises the integrity of the gut cells, communicating to them that they need to shift further apart to allow more nutrients to get to the blood stream. Our bodies are geared for survival - in periods of stress, we require more nutrients to escape 'danger'. This shifting of the gut cells (or increased intestinal permeability) causes food fragments to pass into the blood stream that were never intended to be there. Often the body then mounts an immune response against these 'intruders' which paves the way for food intolerances and allergies.
When we sit down to eat a meal and are feeling stressed, what happens? We eat quickly. Shovel the mouthfuls in and are not present or thankful for the meal about to be consumed. Our bodies interpret this as danger and divert blood supply away from our digestion (parasympathetic nervous system) and sends it to our vital organs; the areas of our bodies vitally required to get us out of danger.
One of the best ways to activate our parasympathetic (rest and digest; feed and breed) nervous system is to breathe properly. Breathing is our connection to our autonomic nervous system. Breath leads, body follows.
Short, shallow, quick breaths tell the body, you are in danger. Blood is diverted away from digestion and the cascade of stress hormones are triggered. Prolonged, deep, slow breaths that move the tummy up and down tell the body it is safe. The parasympathetic (rest and digest) nervous system is activated and focus and energy returns to a state of rest and digestion.
Vanuytsel, T et al 2013, 'Psychological stress and corticotropin-releasing hormone increase intestinal permeability in humans by a mast cell dependent mechanism', Gut, vol. 0, p. 1-7
Weaver, L 2014, Dr Libby's The Calorie Fallacy: Stop Dieting, Start Nourishing, Little Green Frog Publishing Ltd.