ABSTRACT
Introduction When a person swallows, the ingested food or fluid passes through the oesophagus (gullet) and on into the stomach because of a sequential wave of motility, coordinated by the medulla oblongata and vagal innervation. At the upper end of the oesophagus, a muscular sphincter is normally kept closed, to prevent the swallowing of air during breathing. At the lower end, a second sphincter is also normally closed, restricting the reflux of acid and bile from the stomach into the oesophagus. During swallowing, a wave of contraction (peristalsis) passes along the length of the oesophageal wall at a speed of about 2 m/s, propelling the fluid or food forward, and the lower oesophageal sphincter relaxes briefly as food reaches the entrance to the stomach.1 Disorders in this process lead to difficulties in swallowing (dysphagia) and chest pain as acid is regurgitated from the stomach and encounters the oesophageal wall.2 Physiology texts provide relatively little information as to how physical activity affects the behaviour of the oesophagus. Although many endurance athletes ingest nutritious fluids while they are actually competing, there are only a few studies concerning the effects of sport participation upon the mechanics of the healthy oesophagus.3-8 Indeed, the classical and comprehensive review of Ingelfinger1 made no reference to any changes in oesophageal function that might be brought about by exercise. In this chapter, we look at available information on oesophageal function during exercise, including a possible increase in the risk of gastro-oesophageal reflux during vigorous physical activity, and the clinical problems caused by such reflux are considered in some detail. We next discuss the possible value of moderate exercise in preventing reflux, and the risks of increased reflux associated with vigorous physical activity and athletic participation. Recommendations are made for the treatment of this condition, and note is taken of the potentially serious complications, including oesophageal ulceration and haemorrhage, a permanent narrowing (stricture) of the oesophagus, a squamous cell metaplasia of the oesophageal lining and the development of an oesophageal adenocarcinoma.
