It’s one of the best exercises you can do, but running can be a challenge if it upsets your stomach. A significant number of recreational runners report experience nausea and stomach upset when they hit the pavement for their daily workout. What causes nausea when running – and what can you do about it?
Exercise Nausea: What Causes Nausea When Running?
Nausea while running may be related to what or how much you eat before a workout. Running requires a great deal of leg work – which requires energy. To meet the energy demands of the hard-working leg muscles, the body directs more blood flow to them. Unfortunately, this decreases the amount of blood flow the intestines get. If you eat too much before running, your pre-exercise snack won’t be digested as quickly. If what you eat happens to contain fat, it’ll further delay intestinal emptying.
Sometimes nausea when running comes from not eating or drinking enough. If you haven’t eaten carbs in many hours and you try to run “the long one”, you may experience glycogen depletion or even a drop in blood sugar levels. This can cause fatigue, lightheadedness, and nausea. Dehydration from not drinking enough fluids can do the same thing.
Is there a way around this problem of exercise nausea? Eat a small snack that contains complex carbohydrates and protein, but little or no fat, about two hours before running. Drink plenty of water to stay well hydrated – and avoid caffeine. Take along a water bottle if you plan on running for more than an hour, or if it’s warm outside. Sip, but don’t guzzle water during your workout.
Other Causes of Nausea When Running
Another common cause of exercise nausea is GERD. GERD is a condition where the lower esophageal sphincter doesn’t close firmly, and food, liquids, and digestive juices move backwards into the esophagus. This leads to abdominal bloating, nausea, and burning in the chest.
Snacking too close to running, eating too much or eating the wrong foods, and drinking caffeinated beverages makes the symptoms worse. Again, the key is to eat a small snack two hours before a run – and stay away from caffeine. If you have frequent GERD that’s unrelated to running, see a doctor for treatment.
Another underappreciated cause of exercise nausea is aerophagia. Aerophagia simply means swallowed air. Some people swallow air subconsciously when they’re anxious, and others do it when they exercise or run. Aerophagia can lead to uncomfortable stomach bloating, burping, and nausea.
One way to prevent this aerophagia is to make a conscious effort to breathe through your nose rather than through your mouth. Some runners who have this problem may benefit from taking an over-the-counter chewable tablet that contains simethicone – such as Gas-X.
Nausea When Running: The Bottom Line?
If you continue to have symptoms despite making these changes, see your doctor. Some medical problems such as a peptic ulcer or gall bladder disease can cause nausea when running – and you don’t want these conditions to go undiagnosed.
Merck Manual. Eighteenth Edition. 2006.