Exploring the gut-exercise link: A systematic review of gastrointestinal disorders in physical activity

Table 2 Summary of studies evaluating the effect of exercise on gastroesophageal reflux disease

Ref.	Type of article	Age of patients	Summary of study characteristics	Outcome
Djärv et al[96]	Population-based survey	40-79 years	Cross-sectional study assessing the association between PA and GERD in 4910 participants. PA frequency was categorized (low, intermediate, high), and analyses stratified by BMI. GERD was defined as heartburn or regurgitation at least once weekly	Intermediate PA decreased GERD risk among obese individuals (OR = 0.41, 95%CI: 0.22-0.77). No significant association found for non-obese individuals
Sodhi et al[97]	Clinical trial	Not specified	25 GERD patients confirmed by 24-hour pH monitoring performed a 30-minute bending exercise regimen. Esophageal reflux was assessed using 24-hour esophageal pH monitoring before and during exercise	Bending exercises significantly increased reflux time during exercise (P = 0.02). Reflux was more pronounced in combined refluxers than upright refluxers
Mendes-Filho et al[98]	Prospective clinical study	Not specified	39 GERD patients (29 with erosive GERD, 10 with non-erosive GERD) underwent ergometric stress testing with 24-hour pH monitoring. Lower esophageal sphincter pressure and BMI were assessed	High-intensity exercise exacerbated reflux in erosive GERD patients. Light or short sessions of PA had no impact on GERD, regardless of BMI
Yu et al[99]	Systematic review/meta-analysis		Meta-analysis of 33 studies with 242850 participants examining the association between PA and GERD risk. PA levels were stratified, and subgroup analyses (age, smoking status) were conducted	PA reduced GERD risk (RR = 0.80, 95%CI: 0.76-0.84). Older adults and smokers benefited the most. 150 minutes/week of PA reduced GERD risk by 72%
El-Serag et al[100]	Cross-sectional study	Mean age: 51.4 years	Examined the relationship between BMI, waist circumference, and GERD using 24-hour pH monitoring in 206 patients. Anthropometric measures and esophageal acid exposure were analyzed	BMI > 30 kg/m2 associated with increased esophageal acid exposure. Waist circumference partially mediated the effect of BMI on GERD risk
Karrfalt[102]	Case report	Not specified	This is a single patient case report describing a novel exercise for strengthening the lower esophageal sphincter. The exercise involves swallowing food while kneeling with the head lower than the stomach	After several months, the exercise eliminated GERD symptoms, with improvements sustained even after discontinuing the exercise regimen

GERD: Gastroesophageal reflux disease; BMI: Body mass index; OR: Odds ratio; CI: Confidence interval; PA: Physical activity; RR: Risk ratio.