PARIS – Frank Zerbib, MD, head of the department of gastroenterology at Bordeaux (France) University Hospital, broke them down during a session dedicated to exercise, which was the common theme of the JFHOD 2023, a French-speaking hepato-gastroenterology and digestive oncology conference held this year in Paris.
A contributing factor
Several factors can affect how exercise causes gastroesophageal reflux.
“Vigorous,” or mainly sports-related, exercise has a detrimental effect on GERD. Approximately 60% of athletes are said to report GERD symptoms connected to an increase in abdominal pressure. This is not because of obesity, but because of the abdominal contraction that occurs during exercise.
Other pathophysiological factors at the root of exercise-induced GERD can be involved in this phenomenon, namely a decrease in lower esophageal sphincter (LES) pressure and esophageal motility, in addition to phases of dissociation between the LES and the diaphragm, which is when most GERD episodes occur.
In such contexts, “it would appear that sports-related exercise has a relatively detrimental effect on the gastroesophageal junction and anti-GERD mechanisms,” said Dr. Zerbib. Meta-analyses provide answers to some questions, but not all; the situation is much less clear when it comes to non–sports-related exercise.”
Not so simple
“Taking into account only patients whose GERD has been confirmed through esophageal pH monitoring, exercise does not appear to significantly impact GERD symptoms or the characteristics seen on pH monitoring,” said Dr. Zerbib.
These results come from a study of 100 patients whose exercise level was assessed using the International Physical Activity Questionnaire and expressed using the standard metric of metabolic rate by minutes of performance during a week (METs-minute/week).
This questionnaire is used for most studies that assess exercise and separates patients into three groups (low, moderate, or high) based on their level of exercise. In essence, it considers the duration of exercise but not the type (that is, professional, recreational, and so on) or intensity, resulting in a key methodological issue to consider during the analysis, for example, of the results of a large meta-analysis on the topic.
The meta-analysis in question included 78,000 patients, of whom 10,000 had GERD symptoms.
Based on the results, exercise decreases the risk of GERD by about one-third, after adjustment for body mass index (BMI). “This last point is important,” Dr. Zerbib noted, “since adjusting for BMI without providing the nonadjusted data fails to identify whether exercise decreases the risk of GERD because of the effect on the BMI.* What’s more, when it comes to complications of GERD, like Barrett’s esophagus or adenocarcinoma, the data are far fewer and less robust, with negative case-control studies for the most part.”
One of these two studies, which concerned non–sports-related exercise and the onset of Barrett’s esophagus, reported no association (odds ratio, 1.19; 95% confidence interval, 0.82-1.73).
“Exercise considered vigorous (sports-related) contributes to GERD by altering the antireflux barrier (LES/diaphragm dissociation) and increasing constraints on the esophageal junction (abdominal pressure). In the general population, regular exercise likely decreases the risk of pathological GERD. When it comes to complications of GERD, the data are not very robust, mostly because the studies omitted several exercise-related (healthy lifestyle) factors,” said Dr. Zerbib.