Runner’s Stomach – What is it? Causes & Preventions – UPDATED 2022

Having runner’s stomach (commonly known as runner’s gut also) is something most runners dread. However, it is just as common as shin splints and cramps. Reports have found that more than 30% of runners have experienced runner’s stomach at least once in their running career.

So, what is runner’s stomach, and what causes it?

In this article, we look at:

– What causes runner’s stomach
– How to prevent it
– What the symptoms are
– How long it lasts
– What is the best cure

So, if you want to know more about what causes this stomach issue when running, continue reading.

What is Runners Stomach?

First, let us explain what runner’s stomach is.

Runner’s stomach is an issue during running that causes cramping, gas, diarrhea, and often results in the sudden urge to go to the bathroom. It is also called, runner’s gut and runner’s trots. However, they all related to GI distress during a run

So, what causes GI distress during a run?

Below are some of the most common contributing factors of runner’s stomach.

– Running Mechanics
– Stress
– Pre-run nutrition

The main causes of stomach problems related to reduced blood flow to the gut, diet choices, and general mechanics of running. Other things like hormones can play a big part in causing an upset stomach while running. However, it is not as common as the others.

So what does running mechanics have to do with stomach issues? Well, the longer and harder you run, the more blood flow is directed away from your digestive system. That means the blood flow is directed to the heart and working muscles more. This means the reduced blood flow and motility in the gut end up causing symptoms of runner’s stomach ( again also known as runner’s trots or runner’s gut).

The repetitive motion of running has also been known to cause GI distress in the stomach. However, this is not as uncommon as the above cause.

Acute (short-term) Stress
Running is hard on the body, no matter how far or hard you run. So it is not surprising the body perceives running as a form of stress. Since running increases heart rate and releases hormones ( cortisol, adrenaline, and noradrenaline), it’s common that the body diverts blood flow from the GI tract. Which can also cause intestinal microbiota composition problems. Leaving you will the feeling of an upset stomach.

Nutrition
The most common cause of stomach issues when running is nutrition and your diet. Around 60% of people that have stomach issues during a run are caused by eating the wrong food before running. That means stomach comfort (or discomfort) is largely influenced by what you eat prior to and during your run.

Eating the wrong type of food, or even eating too close to your run can cause a rath of problems in the stomach.

Cramping, nausea, and bathroom stops are all common with people that have upset stomachs from eating foods high in fiber, and high in fat. So, it is usually recommended that you stay away from foods high in fat and fiber.

Runner’s Stomach Symptoms – What Are They?

If you are experiencing symptoms of runner’s stomach, these are some of the most common discomforts you may have to deal with. These include:

– Stomach cramps
– Nausea
– Dehydration
– Emergency bathroom stops
– Vomiting
– Diarrhoea

However, Vomiting and nausea are usually fairly uncommon, but it still happens to a small percentage of runners. Stomach cramps, diarrhoea, and emergency bathroom stops are usually the most common symptoms. Just look at any big marathon event or Ironman triathlon. You will find hundreds of people along the course stopping to use one of the on-course toilets.

For most people, stomach issues aren’t a regular occurrence and typically happen out of nowhere, or when eating food they haven’t eaten before. This includes both before and during a run.

So, if you are experiencing regular toilet stops during a run, or an upset stomach often while running, speak to your local doctor and dietitian. They can check both your diet and health condition. That way you can see what is the root cause of your upset stomach.

How Long Does Runner’s Stomach Last?

Everyone experiences different symptoms of runner’s stomach. Often it will start in the middle of the run and continue on for some hours afterward. So, for most people, it will last for 3-4 hours after their run. However, some may experience issues up to 24 hours after their run. But this is rather uncommon.

If after 24 hours you are still experiencing any of the symptoms we have described in this article, you may need to seek medical advice, as it may be a sign of another medical condition.

Best runners Stomach Cure

Unfortunately, there isn’t a single way to cure an upset stomach during and after running. The best runner’s stomach cure is actually a combination of things. These include:

– Avoiding trigger foods (foods high in fat, and fiber)
– Taking probiotics regularly
– Staying hydrated
– Eating more than 1 hour before you run

If you combine these simple things together you are less likely to have a stomach issue during and after a run. However, since everyone is different, it is wise to trial different methods, as some of the above will have less effect.

If you have tried every possible cure and you are still having issues, the best way to cure stomach issues is to book an appointment with a dietitian. A dietitian can help look at your diet and pre-run nutrition and find the cause of your upset stomach.

Alternatively, if that has no effect, try looking to get a running gait analysis. This may find areas in your technique that could cause an upset stomach.