Reflux symptoms are common among athletes and can have a negative impact on athletic performance. At present, the mechanisms underlying excess reflux during exercise are still poorly understood. The aim of this study was to investigate the effect of exercise on reflux severity and examine the underlying reflux mechanisms.
Healthy sporty volunteers were studied using both high-resolution manometry and pH-impedance monitoring. After a meal and a rest period, subjects ran on a treadmill for 30 min at 60% of maximum heart rate, followed by a short rest period and another 20-min period of running at 85% of maximum heart rate.
Ten healthy volunteers were included. Exercise led to a significantly higher percentage of time with an esophageal pH<4 and a higher frequency and duration of reflux episodes. Moreover, exercise resulted in a decrease in contractility and duration of peristaltic contractions. The minimal lower esophageal sphincter resting pressure decreased during exercise, whereas the average and maximum abdominal pressure both increased. Importantly, the percentage of transient lower esophageal sphincter relaxations (TLESRs) that resulted in reflux significantly increased during exercise and all but one reflux episode occurred during TLESRs. In six subjects a hiatus hernia was detected during the exercise period but not during rest.
Running induces gastroesophageal reflux almost exclusively through TLESRs. These are not more frequent during exercise but are more often associated with a reflux episode, possibly due to increased abdominal pressure, body movement, a change in esophagogastric junction morphology, and a decreased esophageal clearance during exercise.