Fitness / Running

Why Do I Have to Go to the Bathroom During a Run?

It's about time we talked about it.

Ever feel like you have to go to the bathroom during a run? You’re not alone. And when it comes to skipping over discussing this uncomfortable topic, you’re also not alone.

Most runners are well-acquainted with the “I need to go now” sensation that always seems to pop up mid-run—usually five miles into a trail run with nary a port-a-potty in sight.

We spoke to Dr. Niket Sonpal to get the scoop on three reasons why gastrointestinal (GI) issues occur for runners, and general tips to prevent needing the bathroom during a run.

Reason #1: You’re, well, running.

“The jostling motion of running sometimes irritates the intestines, along with stomach muscles squeezing our intestines—which causes the classical sensation of wanting to poop,” explains Dr. Sonpal.

In addition to that, blood moves away from the GI tract to assist the major working muscle groups. “When you shut down that blood flow, it causes high physiologic stress, such as cramping.”

In other words, the very act of running itself will create an urge to go. So, if you love running, be prepared to figure out how best to handle it for your own body. And don’t be embarrassed.

In a study of ultra marathoners, 96% experienced gastrointestinal symptoms while running. Meaning, it happens to everyone, whether you’re training for your first race, lacing up for treadmill speedwork, or hitting the pavement outdoors.

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Reason #2: You’re dehydrated.

Some runners will actually avoid drinking a lot of water before, during, or after a run, simply to skip the urge to go to the bathroom. It makes sense, but can lead to dehydration.

So be mindful about water intake on a regular basis, and then be sure to drink plenty of fluids a couple hours before you head out for a run. Also, Dr. Sonpal recommends avoiding carbonated water as a source of hydration; it may expand your stomach and make you feel full, but it won’t actually let you take in as much water as you need.

Reason #3: You literally just ate—and you chose the wrong foods.

Two of the main culprits for GI distress? When you eat and what you eat. “A common precaution many runners take is to avoid high-fiber foods that pass through the system quickly, and cause the need to defecate,” says Dr. Sonpal. “Stay away from gas-producing foods before a run, such as wheat, corn, and potatoes. And avoid vegetables like broccoli, cabbage, lentils, and cauliflower.”

While a fiber-rich diet is great for healthy digestion as a whole, it can cause diarrhea and cramping during a run. This makes your stomach and intestines work harder than necessary. You may also want to pay attention to artificial sweeteners, often found in gum and snacks, which can cause problems.

Finally, even though caffeine can lead to better workout performance, research shows compounds in coffee can speed up how fast your gut moves, so you’ll want to again give yourself at least an hour after drinking a cup of jo. Because many race-friendly fuel sources include caffeine, like gels or chews, you may want to experiment with different brands and flavors to see what works best.

What to try instead:

Talk To Your Doctor

Even if you adore running as a form of fitness, the physical stress involved plus diet and nerves can lead to serious stomach problems.

“If you are experiencing digestive issues, particularly blood in the stool, heartburn with running, or pain in the abdomen—go see your doctor,” says Dr. Sonpal.

Additionally, if you regularly need to use the bathroom during a run or face consistent cramping, intense diarrhea, or have a history of Crohn’s Disease or Irritable Bowel Syndrome, check in with your healthcare provider to stay safe and healthy for every run.

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