Exercise-induced reflux is a real and fairly common pattern, and it happens through a few different mechanisms depending on the type of activity.
Why certain movements trigger it
High-impact activities like running can jostle stomach contents, while exercises that involve bending forward or inverting the body (certain yoga poses, some core exercises) put direct pressure on the stomach and LES. Even without those specific movements, general increased abdominal pressure during intense exercise can push against a already-weak LES.
Timing relative to meals matters most
Exercising on a full stomach is one of the most reliable triggers — waiting two to three hours after a meal before a workout reduces symptoms significantly for a lot of people. A small, easily digestible snack (rather than a large meal) closer to workout time is usually better tolerated than exercising right after eating or on a completely empty stomach if that itself causes discomfort.
Adjustments worth trying
Swapping high-impact cardio for lower-impact options on days symptoms are already active, avoiding forward-bending exercises immediately after eating, and staying well hydrated (dehydration can worsen reflux) are all practical adjustments that let most people keep exercising without triggering symptoms.
