ABSTRACT
Little attention has been paid to the role of the gastrointestinal (GI) tract, and especially the stomach, in space sickness. The stomach may serve both as a target organ and a potential etiological factor for the space adaptation syndrome. Many of the symptoms associated with motion sickness on earth are also seen with space sickness, including GI disturbances such as anorexia, gas or belching, and epigastric discomfort or awareness, with a sudden relief from symptoms after vomiting. The stomach influences gastric motility through its interaction with two distinct motor regions. The proximal stomach receives and stores boluses of food from the esophagus. In the intact stomach, gravity ordinarily exerts only a small influence on the rate of gastric emptying of both liquids and solids. The effects on the stomach depend upon the amount, duration, vector direction, individual variations, and other environmental factors.
