The phenomenon of stress shaking the stomach is clearly explained today by the concept of the gut-brain axis. Beyond simple communication, our brain and gut are closely connected like twins, exerting an enormous influence on each other's condition.
When under stress, the brain immediately recognizes an emergency and activates the hypothalamic-pituitary-adrenal axis. In this process, stress hormones such as cortisol and adrenaline pour out. These hormones switch our bodies into fight-or-flight mode, at which point digestive function is pushed down the priority list. Digestion cannot take priority when being chased by a lion. Consequently, blood flow volume to the stomach decreases, digestive enzyme secretion is suppressed, and malfunctions occur, such as gastrointestinal motility slowing down or becoming abnormally fast. This serves as a modern interpretation of how the stagnant qi mentioned in the Donguibogam affects the stomach.
Additionally, there are neurons in our stomach second in number only to the brain, which are known as the enteric nervous system. This enteric nervous system receives instructions from the brain, but it also functions independently to regulate the digestive process. The brain and the enteric nervous system constantly exchange information via the highway called the vagus nerve, and stress disrupts the balance of this vagus nerve. Excessive stress stimulates the sympathetic nerve and suppresses the parasympathetic nerve, which can induce excessive stomach contractions, hypomotility, and even gastric hyperacidity. Symptoms such as acid reflux, heartburn, and bloating easily appear at this time.
Chronic stress also increases intestinal permeability, inducing leaky gut syndrome. When the intestinal barrier becomes loose, harmful substances or microorganisms in the gut leak into the bloodstream, triggering a systemic inflammatory response, which creates a vicious cycle that further worsens gastrointestinal symptoms. Furthermore, it negatively affects the gut microbiota environment. When beneficial bacteria decrease and harmful bacteria increase, it can lead not only to indigestion, but also to decreased immunity and mood changes. The phlegm-fluid mentioned in the Donguibogam can be seen as a metaphorical expression of the overall state of this gut environment imbalance, inflammatory response, and the resulting accumulation of waste products.
Ultimately, stress-induced gastrointestinal disorders are the result of complex reactions from our body's integrated nervous system, endocrine system, and immune system. It is important not to ignore the emergency signals that the brain and stomach send to each other, and to make efforts to restore the balance of our body and mind, just as taught by the wisdom of the Donguibogam.
