Gastroesophageal reflux disease (GERD) is a significant public health concern, impacting approximately one third of the population in the United States. GERD is characterized by the flow of acid from the stomach back into the esophagus, causing symptoms or potentially tissue damage after repeated or prolonged exposure. Most often, symptoms present as heartburn, a burning sensation behind the breastbone radiating to the neck or throat, or regurgitation, the sour or bitter taste of acidic fluid. Atypical symptoms such as cough, hoarseness, asthma, laryngitis, or chest pain may present, sometimes delaying diagnosis and proper treatment, and some may even present asymptomatic (Locke, 2019). If left untreated, GERD can lead to permanent tissue damage, Barrett’s esophagus, and cancer. Potential risk factors for GERD symptoms include smoking, pregnancy, heredity, obesity/overweight, hiatal hernia, and diet. For some, exercise may cause symptoms. The relationship between exercise and gastroesophageal reflux disease (GERD) is a double-edged sword in that for some it improves symptoms and for others it can exacerbate them.
In many cases, GERD results from relaxation or improper closing of the lower esophageal sphincter (LES). The esophagus is a long tube that is located behind the trachea and connects the pharynx, or throat, to the stomach. At the top, it has an upper esophageal sphincter (UES), which is a group of muscles that are used to control food when swallowing and to prevent food from going down the trachea. The LES is a group of muscles located at the bottom of the tube where the esophagus meets the stomach, functioning as a one-way valve to keep stomach acid contents from travelling in reverse.
Depending on the individual, exercise may improve GERD symptoms or it may precipitate them. Being overweight is a risk factor for having GERD due to pressure buildup on the stomach from adipose tissue. For those who are overweight, a 10% reduction in weight has been shown to reduce GERD symptoms (Colorito, 2018). One 2016 study of participants with general or abdominal obesity showed that a reduction in BMI of greater than 2 kg/m2 and a decreased abdominal circumference of greater than 5 cm resulted in improved GERD symptoms (Park et al., 2016). Still, GERD may occur in even the fittest of individuals. A 2016 study examining the possible mechanisms by which symptoms may occur in runners found that running caused transient LES relaxations that more often lead to GERD episodes than at rest, possibly due to increased abdominal pressure, decreased contractions of the esophagus, body movement, and changes in the shape of the area where the esophagus meets the stomach (Herregods et al., 2016).