Exercise, specifically running, induced changes in healthy individuals that are similar to those observed in patients with GERD, and that exercise-induced reflux episodes are caused almost entirely by transient lower esophageal sphincter relaxations, according to a recent study.
“Previous studies have shown that strenuous exercise can induce excessive reflux, both in patients with GERD and in asymptomatic healthy subjects, and that this mainly occurs during vigorous exercise, suggesting that strenuous physical activity can be a risk factor for GERD,” the researchers wrote. “Currently, the mechanisms underlying excess reflux during exercise are still poorly understood.”
Seeking to better understand the effect of exercise on severity of reflux and its underlying mechanisms, researchers from the department of gastroenterology and hepatology at Academic Medical Center in Amsterdam, recruited 10 healthy, physically active volunteers without GERD (4 women; age 21-41 years; BMI, 16.5-30.7).
All participants had a pH-impedance catheter and a solid-state high-resolution manometry catheter inserted transnasally, after which they consumed a meal and rested for 30 minutes. Then they ran on a treadmill for 30 minutes at 60% of their maximum heart rate, rested for 10 minutes, then ran for another 20 minutes at 85% of their maximum heart rate.
Exercise led to a significantly higher percentage of time with a pH less than 4 compared with resting (P = .018), and it also led to a significantly higher frequency and longer duration of reflux episodes.
With increasing intensity in exercise, contractility, duration of peristaltic contractions, and minimal lower esophageal sphincter resting pressure decreased, whereas average and maximum abdominal pressure both increased.
The percentage of transient lower esophageal sphincter relaxations (TLESRs) that resulted in reflux significantly increased during exercise (41.7% at 60% max heart rate and 50% at 85% max heart rate vs. 0% resting), and all but one reflux episode occurred during TLESRs. Finally, in 60% of participants, a hiatus hernia was detected during the exercise period but not during rest.
The researchers concluded that running increases total reflux time, that exercise appears to cause changes in healthy persons that are similar to the abnormalities observed in GERD, and that exercise-induced reflux episodes occur primarily during TLESRs. “These are not more frequent, but are more often associated with a reflux episode, possibly due to an increased abdominal pressure and due to body movement during exercise,” they wrote. “Moreover, we conclude that exercise induces a transient hiatus hernia in many healthy volunteers and thus a change in [esophagogastric junction] morphology induced by exercise could have a pivotal role. Furthermore, running results in an altered esophageal motility with a decreased contractility and duration that could lead to a decreased esophageal clearance.” – by Adam Leitenberger
Disclosure: One of the researchers reports receiving research funding from Endostim, Medical Measurement Systems, Danone and Given, and received speaker and/or consulting fees from MMS, Astellas, AstraZeneca and Almirall.