Differences in gut microbiota between onset and recovery from acute mountain sickness

Fifteen low-altitude volunteers (3 women and 12 men) participated in this study. All participants were over 20 years old, had no gastrointestinal abnormalities or diseases, were not taking any medication, and had not undergone a colonoscopy in the past three months. The volunteers traveled by train from low to high altitude (approximately 3,500 meters) and stayed at high altitude for 11 days. They exhibited one or more symptoms related to acute mountain sickness (AMS) on the first or second day after arriving at high altitude. During these two days, a total of 25 fresh stool samples were collected, which were classified as the unacclimatized group. After 10 to 11 days at high altitude, all AMS-related symptoms had nearly disappeared, and we collected 24 fresh stool samples during these two days, categorizing them as the acclimatized group.