Feeling Stifled Whenever You Get Angry? Evidence That the Stomach, Not the Intestine, Is Worn Out by Mental Stress

Have you ever heard of the gut-brain axis? It literally means that the brain and gut are closely connected like a highway. Modern medicine clearly explains how stress directly torments our gastrointestinal system through this link. When we experience stress, the brain instantly activates the fight-or-flight response and secretes stress hormones such as cortisol and adrenaline. These hormones decrease blood flow to the digestive system and lower gastrointestinal motility. It is just like dispatching all resources to critical areas such as the brain, heart, and muscles during wartime, pushing non-urgent tasks like digestion to the back burner. It also influences gastric acid secretion, causing heartburn. In particular, the vagus nerve plays a pivotal role in this gut-brain axis. Directly connecting the brain and stomach, it regulates digestive secretion, gastrointestinal motility, and even appetite. When this vagus nerve is stimulated during states of anxiety and agitation, gastrointestinal activity may suddenly slow down, or conversely convulse excessively, leading to symptoms like abdominal pain, diarrhea, and constipation. The expression from Donguibogam that the stomach qi cannot descend can be interpreted in modern terms as an intestinal motility disorder caused by an imbalance in the vagus nerve. The gut contains so many nerve cells and neurotransmitters, such as serotonin and dopamine, that it is called the second brain. These neurotransmitters also play an essential role in regulating mood; when the intestinal environment deteriorates or communication along the gut-brain axis suffers due to stress, it can lead to feelings of depression or anxiety. Furthermore, chronic stress increases intestinal mucosal permeability to cause leaky gut syndrome, and increases pro-inflammatory cytokine secretion to trigger microscopic inflammatory responses throughout the gastrointestinal tract. A significant portion of functional dyspepsia, where the abdomen remains consistently uncomfortable without apparent gastritis or ulcer, is deeply related to these gut-brain axis issues. Ultimately, when peace of mind is shattered, the stomach cannot help but fall ill alongside it.