Digestive system functioning during simulation of microravity effects on humans by means of immersion

The functioning of the digestive system was investigated in ten volunteers after a seven-day dry immersion (DI). The experimental conditions were found to raise the secretory activities of the stomach, pancreas, and liver and to increase the spectral indices of the gastrointestinal tract’s (GIT) electrical activity against the background of an increased insular secretion and decreased gastrin secretion. The elevated GIT electrical activities and changes in their relationships were determined by an increased gastric secretion and elevated intestine tone in fasting subjects and displayed a close similarity to changes induced by caffeine stimulation and those arising during long-term head-down tilt bed rest (HDTBR) or spaceflight.