PARIS, France — Exercise has a variable impact on the onset of gastroesophageal reflux disease (GERD) symptoms. The mechanisms at play are complex and seldom studied. Frank Zerbib, MD, head of the department of gastroenterology at Bordeaux 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 Zerbib. Meta-analyses provide answers to some questions, but not all: the situation is much less clear when it comes to nonsports-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 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, etc) 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 BMI. “This last point is important,” 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 nonsports-related exercise and the onset of Barrett’s esophagus, reported no association (odds ratio, 1.19; 95% CI, 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 Zerbib.
Several Confounding Factors
It’s difficult to issue an opinion under these conditions. There are several confounding factors that studies rarely address. Although the studies always included factors such as age, sex, or BMI, other parameters related to a healthy lifestyle, whether directly or indirectly connected to exercise, were never mentioned. Indeed, diet (such as high calorie or high fat) is known to lead to an increased incidence of GERD. The same goes for alcohol use. Occupation also likely plays a role, but the studies do not mention this.
“So, it’s easy to imagine that a patient who regularly exercises likely eats healthier than a sedentary patient, which comes with the likelihood of a lower risk of developing GERD symptoms,” said Zerbib. “Overall, evaluating the impact of exercise on GERD is no small feat. It can be said with relative certainty that exercise contributes to GERD through a proven pathophysiology. In the general population, however, exercise likely reduces the risk of GERD but not of its complications. Other than the impact on weight and abdominal obesity, the reality is that a lack of exercise is associated with a less healthy lifestyle and, therefore, behaviors that contribute to GERD.”
Zerbib reported no conflicts of interest connected to this presentation.
This article was translated from the Medscape French Edition.
* From a pathophysiological standpoint, the evidence is clear that a high BMI increases the gastroesophageal pressure gradient and dissociation between the LES and the diaphragm, whether temporarily or permanently, as in the case of a hiatal hernia. Abdominal obesity increases constraints on the gastroesophageal junction and results in a two- to threefold increase in the risk of GERD and its complications.
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