How Can You Best Manage Runner's Trots?

Imagine you're in the middle of a long-distance run and nature calls without a bathroom in sight. Doesn't sound fun, right? You may be familiar with the uncomfortable feeling of runner's trots. Runner's trots refers to digestive problems that occur during or after a run. Also known as runner's diarrhea or runner’s stomach, it's characterized by frequent, loose bowel movements. Other common symptoms may include stomach cramps, nausea, and an urgent need to go to the bathroom.

While it's usually not serious, runner's trots can cause severe symptoms that require medical attention. Read on to learn more about runner's trots and what you need to do if you experience this condition.

What causes runner’s trots?

Many people experience exercise-related digestive problems that affect their performance. But researchers are still unsure what causes runner's trots. Several factors may cause exercise-induced gastrointestinal (GI) issues, including: 

• Physiological or bodily changes 

• Mechanical or physical changes 

• Exercise duration, intensity, and environment  

• Diet and nutrition 

Physiological changes 

Running and other high-intensity exercises reduce blood flow to your gut. This change allows more blood to flow to your heart, lungs, and working muscles. But it may also irritate intestinal cells involved in the digestive process. Your intestines may not be able to absorb water and nutrients as well, which could contribute to loose stools. Reduced blood flow may also disturb the bacteria in your gut and produce toxins that cause GI stress. 

Finally, having an underlying GI disorder, such as irritable bowel syndrome, may also contribute to an increased risk of runner's diarrhea. 

Mechanical changes 

The mechanics of running, or the way your body moves during a run, can affect your speed and risk of injury. The up-and-down movement of running can also increase pressure on your stomach. This added pressure may lead to digestive problems. 

Exercise intensity and duration 

Doing high-intensity exercise for long periods of time increases your risk of stomach problems. It may be because vigorous workouts like running can reduce gastric emptying time (how long it takes to digest food). 

High-intensity exercise releases stress hormones like adrenaline and cortisol. You might notice signs of these hormonal shifts –– like increased heart rate, sweating, and nervousness –– before a race. And recent evidence shows that anxiety and stress can contribute to runner's diarrhea. 

Exercise environment 

Exercising in hot weather puts you at risk of hyperthermia. Hyperthermia refers to illnesses that cause an unusually high body temperature. It happens when your body is exposed to heat and can't cool itself properly. 

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Extreme heat may also affect gastrointestinal function. Heat increases blood flow to the skin to help regulate your body temperature. But more blood to the skin means less blood and oxygen to the gut. This can cause intestinal changes that lead to leaky gut syndrome or diarrhea. 

Dehydration 

Dehydration occurs when your body doesn't have enough water to sustain normal functions. Higher body temperatures while exercising and fluid lost through sweating play a role in dehydration. And researchers believe that dehydration is also a risk factor for runner's trots.

Diet

Your diet can cause or contribute to runner's diarrhea. Certain ingredients may trigger stomach problems. Research is ongoing, but you may want to consider avoiding the following to help prevent runner’s diarrhea:

• Fiber: High-fiber foods like whole grains, fruit, and vegetables are good for you. But too much fiber has been linked to GI issues such as diarrhea and constipation. A study of triathletes found that consuming high-fiber foods before exercise caused more stomach cramps than other foods. 

• Fat: Fatty foods, such as butter and cheese, may be harder to digest. They can cause inflammation in the digestive tract and issues like diarrhea or constipation. 

• FODMAPs: FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. These are all types of sugars that your small intestine may not absorb well, contributing to GI distress. Research on how FODMAPs affect runners is limited. But a low-FODMAP diet may help those with symptoms of irritable bowel syndrome. So it’s worth considering if you are experiencing runner’s trots. 

• Protein: While eating enough protein is important to maintain muscle mass and strength, too much protein can lead to GI upset. High amounts of protein can change the bacteria in the gut, causing stomach problems.

• Caffeine: Caffeine is a stimulant. So caffeinated beverages like coffee can stimulate the colon. This will get your bowels moving and could contribute to diarrhea.

Ongoing research suggests that eating foods with multiple transportable carbohydrates (MTC) may cause less gastrointestinal distress. MTCs are foods that have a combination of sugars.  Interestingly, some of these contain the same sugars in FODMAPs, but the combination seems to be key. Combinations may include glucose and fructose or maltodextrin and fructose. Some energy bars or drinks are formulated with MTCs. There may be other potential benefits of MTCs, such as enhanced performance. 

How do you treat or prevent runner’s stomach?

Over-the-counter antidiarrheal medications can help treat runner's stomach. And various prevention strategies may help you avoid it altogether. Consider these tips before your next run: 

• Change your pre-run diet. Many runners avoid high fiber, fat, and protein foods before a race. Experts recommend avoiding these and other ingredients like caffeine 24 hours before exercise. Doing so may reduce your risk of gastrointestinal problems like runner's trots.

• Stay hydrated. Dehydration can contribute to runner's diarrhea. Water regulates your body temperature and lubricates your joints, ensuring optimal performance. So proper hydration is essential before, during, and after a run. Check with your doctor or trainer if you are concerned about your fluid intake while running.

• Try not to run at the hottest time of day. Exercising in the heat can increase your risk of runner's diarrhea. So try to avoid running outside at midday, when the sun is usually the hottest. Or consider indoor treadmill runs on particularly hot days. 

• Avoid non-steroidal anti-inflammatory drugs (NSAIDs). The risk is low, but NSAIDs like ibuprofen can cause acute diarrhea. So you may want to avoid pain relievers before a run. 

• Make time for adequate training. Adequate training can improve your running form, speed, and endurance. Lack of training and experience are associated with runner's diarrhea. So these benefits may help you avoid unexpected bathroom trips during your next big race. 

• Keep stress levels low. There's a link between stress and diarrhea. So try to avoid stressful situations before a race. That's easier said than done. But mindfulness-based techniques, like yoga or tai chi, can help relieve stress. 

When should you see a doctor about digestive issues while running? 

Runner's diarrhea is usually benign (not harmful). But it can cause other problems like dehydration. Severe dehydration can lead to serious issues, such as kidney damage or failure. Some signs of dehydration include decreased urine output, dizziness or passing out, and low blood pressure.  

So if you have runner's diarrhea with symptoms of dehydration, it's important to see a doctor right away. You should also see a doctor if you notice blood in your stools. This may be a sign of ischemic colitis, which is essentially a severe form of runner's diarrhea. Conservative treatments usually work for ischemic colitis. But in rare cases, additional interventions, such as surgery, are required. 

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Written by:

Jennifer Clements, MD, MSEd, NBHWC

Jennifer Clements, MD, MSEd, NBHWC, is a board-certified physician and health coach who is passionate about achieving optimal health through healthy lifestyles. Clements is a diplomate of the American Board of Obesity Medicine and the American Board of Integrative Medicine.

Edited by:

Lauren Savage, MA

Lauren Savage, MA, is a health editor at GoodRx, where she focuses on movement, exercise, and healthy aging. She aims to provide readers with the information they need to live healthier, more active lifestyles.

Reviewed by:

Sanjai Sinha, MD

Sanjai Sinha, MD, is a board-certified physician with over 20 years of experience. He specializes in internal medicine.

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