It's uncomfortable and irritating, but burping while running is uncommon. You may be swallowing too much air while running or choosing food -- or drink -- dietary factors that produce too much gas.
When you run, your stomach gets jarred and in some sensitive people, this can be enough to prompt slight reflux. Control what factors you can to reduce belching so you can feel more comfortable as you cover the miles.
Burping while you run is not a completely controllable phenomenon. Some natural changes take place in your body as you exercise that promote burping. Being aware of them can help set your mind at ease; if you do burp while exercising, you needn't worry that you're suffering from a preventable or serious medical condition.
Exercising draws blood flow away from the stomach, which can impede digestion. When this happens, key hormones increase production to move food through the intestinal tract faster than normal and help produce gas. Finally, the jarring of the stomach during exercise can also produce gas, which can cause burping.
Swallowing too much air during exercise is a major contributor to burping on your run. Swallowing air is so common it even has a scientific name: aerophagia.
Taking air into the esophagus while running is not unusual. Even more common, is swallowing air while drinking. For many people, the amount of water competes closely with the amount of air ingested into the stomach. Combining fluid intake while running creates a perfect storm for burping.
Take small sips of water, rather than large gulps, and focus on breathing through your nose, rather than your mouth, as you exert yourself. Don't skip liquids, however, as dehydration leads to a whole other list of problems.
Food is another likely cause of burping while running. For many people, especially the 20 percent of the population who are lactose intolerant, the lactose in milk products causes stomach gas that then gets burped up during strenuous activity.
High fiber food, beans, fructose and sucrose found in candy and soft drinks can also contribute to excessive burping while exercising.
If you think the cause is food-based, then make sure you eat your last meal or snack three or four hours before you run to ensure full digestion. Avoid high-fiber foods and dairy right before your run and stick to easily digested options, such as a banana or slice of toast.
Practicing relaxation techniques and deep breathing exercises can also help minimize the amount of air swallowed. If you want to really train yourself to not swallow air, wear a mouth guard as you run to limit your ability to open your mouth to swallow air.