Looking at the concept of unacclimatization in the Donguibogam from the perspective of modern medicine reveals how scientifically insightful it was. The reasons our gut acts up during travel abroad are complex. While it is easy to assume it is simply due to unfamiliar food, our body reacts to environmental changes in far more delicate ways.
The first factor is infection. The most common cause of travelers' diarrhea is microorganisms such as bacteria, viruses, and parasites. Consuming contaminated water or food in regions with poor sanitary conditions exposes our gut to unfamiliar harmful bacteria. Typical examples include Escherichia coli, Salmonella, and norovirus. These pathogens irritate the intestinal mucosa and secrete toxins, triggering acute diarrhea.
Infection is not the only cause. Travel also places significant stress on the body. Altered sleep patterns from jet lag, tension from an unfamiliar setting, irregular meal times, and cramped seating with dry air during flights all act as stressors. The brain and gut communicate closely through the neural network known as the gut-brain axis. When the brain experiences stress, signals are sent directly to the digestive tract, altering peristalsis and digestive fluid secretion. The stress hormone cortisol can increase intestinal mucosal permeability, promoting inflammation and altering the gut microbiome.
In addition, our body relies on a 24-hour biological clock called the circadian rhythm. When jet lag disrupts this rhythm, intestinal motility inevitably becomes irregular. The gut experiences confusion, resting during the day when it should be active, or becoming active at night when it should rest. This disruption serves as a major trigger for both diarrhea and constipation.
Changes in the gut microbiome are equally important. Each person possesses a unique gut microbiota. When exposed to new water, food, and environments, the digestive tract meets countless unfamiliar microorganisms. This can disrupt the balance between beneficial gut bacteria and harmful bacteria, leading to dysbiosis, which presents as indigestion, diarrhea, or constipation.
Dietary shifts during travel also place a burden on the digestive tract. Low fiber intake, combined with unfamiliar spices or greasy foods, makes proper digestion difficult. Furthermore, dry cabin air and hectic schedules often lead to inadequate fluid intake, which is a primary contributor to worsening constipation.
Bowel trouble during travel is not caused by a single factor alone. It is a natural adaptive response resulting from a combination of infection, stress, circadian rhythm disruption, alterations in the gut microbiome, dietary changes, and dehydration. Modern medicine explains the ancient concept of unacclimatization through these multi-layered physiological mechanisms.
