Effect of esophageal acid and prophylactic rabeprazole on performance in runners

Acid reflux occurs during exercise. The effects of esophageal acid and prophylactic antisecretory treatment on exercise performance are unknown.

To determine 1) the effect of esophageal acid perfusion during exercise on pulmonary function and exercise performance, and 2) whether acid suppression with rabeprazole (RAB) 20 mg x d(-1) increases exercise performance during esophageal acid infusion.

This was a two-phase study. Twenty-four conditioned runners (11 with heartburn, 13 without) completed phase 1. Sixteen runners with heartburn completed phase 2 (RAB). For phase 1, esophageal evaluation, baseline maximum exertion test, and a standard Bruce protocol maximal stress test were performed. Runners were randomized to sham esophageal infusion (NG tube placed in the distal esophagus, no fluid) or esophageal acid perfusion (0.1 N HCl perfused) during exercise. Subjects were crossed over to the alternate perfusion. For phase 2, runners underwent three sessions with both acid and sham perfusion during running; the sessions were randomly conducted on different days at baseline and 8 and 12 wk of RAB 20 mg.

For phase 1, esophageal function and sensitivity were normal. There was no difference in airway resistance or work capacity between groups. The acid-perfusion group significantly decreased time to exhaustion in the no-heartburn group (23.13 to 20.66 min) with a decrease in energy expenditure. For phase 2, time to exhaustion was significantly decreased with acid perfusion at all time points (P < 0.05). Total energy expenditure during exercise was less in each acid-perfusion test. No difference in pulmonary function was present at week 12 versus baseline.

Esophageal acid perfusion decreased performance. In runners with heartburn, suppression of endogenous acid secretion did not improve exercise performance. Changes in cardiopulmonary function do not explain the decreased exercise performance during acid perfusion.