For people with chronic heartburn, too much running and jumping can induce acid reflux. However, the right type of exercise may actually improve the condition.
Short bouts of fairly moderate exercise at least a couple of times a week can cut the risk of gastroesophageal reflux disease, or GERD, in part because it reduces body mass index.
The New York Times reports:
"... [T]he specific exercise is crucial. Scientists found that aerobic exercises with the highest 'agitation of the body,' like vigorous running, consistently induced acid reflux, even in people who did not have chronic heartburn ...
Another factor is body position. Bench presses, leg curls or any other exercise that involves lying flat sharply raise the risk of acid reflux."