The symptoms of heartburn occur when the lining of the esophagus is irritated by stomach acids that have backed up into it. A band of muscle at the bottom of the esophagus is called the lower esophageal sphincter, or LES. The LES opens to allow food into the stomach, and then closes. If this muscle becomes weak, stomach acids can escape. This can cause a burning sensation in the chest or throat, trouble swallowing, a chronic sore throat, bad breath and many other symptoms. Various triggers set off heartburn symptoms; running can be one of them. Lifestyle changes may help control the symptoms.
Too Vigorous a Level
Exerting the body during intense levels of exercise may affect the ability of the lower esophageal sphincter to close properly. Activities such as weightlifting and bicycling may trigger acid reflux; however, more intense exercise such as running seems to be the worst offender, according to a June 1989 article in the "Journal of the American Medical Association."
Heartburn while running can occur in healthy individuals who do not experience heartburn at any other time. If this symptom occurs, it will be necessary to reduce the intensity of exercise to a symptom-free level. It may also help to learn to relax the abdominal muscles while running to decrease the pressure on the LES.
Certain foods can trigger heartburn no matter when it occurs. However, if heartburn only occurs while running, it may be necessary to be careful about the type of food consumed for about one hour before running.
Common foods that cause heartburn include fried or fatty foods, chocolate, peppermint, citrus fruits and drinks, vinegar and tomato products, according to the American Gastroenterological Association. It may also be necessary to avoid caffeine. Large meals may be an additional problem, as a full stomach can make heartburn symptoms worse. Since each case is different, a period of trial and error may be necessary to find personal trigger foods.
Wearing tight-fitting clothing while running can also trigger heartburn symptoms. Clothes that are too snug around the waist place pressure on the abdominal muscles and can hinder the ability of the LES to close properly.