Nausea After Running: 9 Common Causes and Solutions

Whether you’re an experienced runner, or just starting out, chances are you’ve experienced nausea after running or heard of someone who has.

If you’ve ever finished a long run and struggled to get yourself to eat that’s common and we’ve talked about how to help. But if you’re having regular issues with nausea after running, it’s time to check some potential issues and put a stop to it!

While running our body is diverting muscles from digestion to our muscles, which is part of what causes runners trots and other running stomach ailments.

But the urge to vomit is a different level of ick.

Let’s review what might be causing it and find out if we can improve both the run and your recovery!

9 Common Causes of Nausea After Running

As with all issues consider seeking medical advice if this is happening consistently and nothing seems to be helping.

It is NOT an issue you should have all the time.

Remember that while you are running blood is diverted away from your digestive system to your muscles. That means anything that aggravates your stomach could be worse because the body isn’t dealing with it.

1. Digestive System Issues

During running, oxygen-rich blood is redirected from the stomach and other non-essential organs to the lungs, heart, and other working muscles that require it more during high-intensity efforts.

Since your stomach lacks the regular resources to digest nutrients as efficiently as usual, you may end up feeling nauseous and possibly vomiting, especially if you ingest too much fuel while running or too soon after finishing.

Drinking water frequently and early will aid in improved digestion and prevent nausea after exercise because dehydration slows down the digestive process even more.

It’s important to stay hydrated to keep your GI system in good shape and prevent nausea after workouts, but you also need to strike a balance between staying hydrated enough to prevent nausea and without drinking too much.

sick to stomach after running

2. Increased Pressure on Your Stomach

When you run at a high intensity, the intra-abdominal pressure rises, putting pressure on your stomach.

This happens because when you run, you activate your core more and take deeper breaths. When this occurs, the stomach’s contents may be forced back up into the esophagus, and even back to the mouth leading to nausea and vomiting.

This is more likely to happen if you had a lot of food or liquid in your stomach before you went for a run. However, this amount is highly individual, so it’s important to know what your body can handle before a race or run.

Having more food in your stomach during an intense race or workout increases the likelihood of vomiting.

Plus, some runners may suffer from a disorder similar to acid reflux known as gastroesophageal reflux disease (GERD) and are at a higher risk of experiencing this kind of situation. This is because the muscles between the esophagus and the stomach, called the lower esophageal sphincter, are weak and may relax when they shouldn’t.

GERD can be handled with medications or by changing the diet to avoid foods that can irritate the lining of the esophagus, such as acidic foods, tomato products, fatty foods, alcohol, and coffee.

3. Vitamins Before the Run

This will vary by person and by what the supplement is, but specifically taking iron before a run has been shown to cause intestinal issues. The good news is that you actually want to take it within 30 minutes of finishing a workout for maximum absorption…so we’re just switching up the timing!

Other runners have reported that taking any of their vitamins pre-run, almost always leads to stomach pain after.

do not take iron before a run
if having issues move all vitamins to post run

Some vitamins are water soluble, while others are fat soluble.

That means they need sufficient amounts of those in the body to be absorbed and used. Perhaps by sitting in the gut when things are not being digested as normal, they irritate the stomach.

4. Having the Wrong Foods Before Running

Acidic Foods

Before your run, avoid consuming meals and beverages that are very acidic, such as citrus fruits like oranges, berries, and grapefruits, processed cheeses, and liquids such as soda or orange juice.

Acidic foods and drinks make the stomach more acidic. This not only slows down the process of emptying stomach contents into the small intestine but also makes it more likely that someone will throw up.

High Fat or High Protein Foods

Meals and snacks that are high in fat or protein should also be avoided before a workout because they slow down the process of gastric emptying.

In other words, the food remains in your stomach for a longer period of time and may even be present while you are running, giving you the sense of having a brick in your stomach that is difficult to keep down and makes you feel nauseous.

To prevent exercise-induced nausea, avoid eating during the two-hour window before a hard run or race. If you do feel the need to eat, keep it simple and small in size such as toast with peanut butter or a banana.

If diet changes do not prevent nausea and vomiting, take antacids or Pepto-Bismol approximately an hour before running and consult with your doctor to rule out any other condition.

High Fiber Foods

You’ve often heard people mention going a bit lower in fiber the days before a race to prevent runners trots, but for many runners, you need to look at fiber pre-run all the time.

DO NOT cut all fiber from your diet as this will result in a lot of health issues and slow down the good gut function that we want.
Evening runners may need to eat fewer cruciferous veggies at lunch (think broccoli), instead of eating them post-run.
Morning runners may choose to eat oatmeal post-run instead of pre-run.

Keep a log of what you eat before runs to see if a specific food might be causing the issue.

Additionally, make sure you check out how long to wait after eating to exercise >>

3 of the most common nutrition mistakes runners make and how to fix them

5. Drinking Coffee

Don’t throw things at me! I know many of you NEED your pre-run coffee.

But if you’re constantly feeling nausea after running then this is another one that you need to test.

Coffee can increase stomach acid
Again your body is not dealing with digestion while running
This leads to the stomach feeling irritated

6. Overexertion

The most commonly accepted reason for nausea after running is simply running too hard. It’s why we have that urge to vomit at the end of an all out mile race or 5K.

But it can also happen with long runs.

I read one article that said vomiting after running is common for new runners. I BEG TO DIFFER. You should not be throwing up, that’s a clear sign you are not running easy enough, which is necessary to increase your endurance.

Dehydration is the main culprit with most races or long runs. Sweating heavily and not taking in enough electrolytes can lead to an imbalance that creates that sick feeling.
Build of up metabolic waste that the body cannot deal with because all your energy is going to your muscles.
While intensity is needed as a stimulus, you shouldn’t be going to this level all the time.

7. Stopping Too Quickly

If you suddenly slow down after your last interval or after you cross the finish line, your stomach may not be able to handle the rapid change in intensity and you may become ill. This can become much more severe if you put in a significant amount of effort over the last stretch of the race.

Stay on your feet and keep moving to give your body a chance to readjust and prevent cramping in your stomach. Also, don’t drink too much sports drink or eat too fast.

Instead, slowly sip on some water, continue walking, and allow your body to return to its normal state.

8. Excessive Dehydration

If you tend to sweat a lot, you are at a higher risk of exercise-induced nausea. This is because if you lose more than 4% of your body weight while running, your gut stops properly absorbing liquids, which results in nausea.

If you’re already dehydrated before you start working out or running, you’re going to feel even worse.

And any runner who thinks that spilling your guts or vomiting profusely is a sign of a well-run race is wrong. When you throw up like that, you can hurt the lining of your stomach, which can make digestion even harder.

9. Heat and Humidity

Last but not least is the heat.

We already know that running in heat and humidity increases our heart rate. But you may not also translate that to mean that you may have stomach issues. As a way to cool the body down, blood flow is diverted to the skin, which has an impact on digestion.

This means that the body is working harder with every mile to cool itself, maintain an electrolyte balance, and keep pumping oxygen to all of your muscles.

That also means that the big overexertion issues listed above are going to pop up again even at easier levels of training.

To prevent this, practice fueling during training runs to determine how much fuel your stomach can tolerate during a race or long run. Also, if you take energy gels, have them with water to help digestion. Even when you’re not running, simple sugar is difficult to digest, so consuming too much sports drink or gels at once could be risky.

If you start hitting that vomit point while running in the heat, STOP. That’s a sign you are trending towards a bigger issue.

What To Do If You Get Nauseous After Running?

If you finish a run and are feeling ready to toss your cookies, there are a few things that can help. How quickly they work can often depend on how depleted you are or how intensely you went.

Slow down. You may not want to simply sit down, but instead try a very slow walk.
Try taking slow and deep breaths. If still feeling bad after the walk, lay down with legs up the wall.
Start sipping electrolytes. Don’t guzzle them, that could lead to different gut issues. But the sipping will help get you hydrated and help get the body back in balance.
Sucking on a peppermint or ginger chew is another way to start sending some soothing signals.
Work on calming your nerves. This is one that impacts more runners on race day than they realize. Start implementing some tools to deal with race day nerves or worries about specific workouts.

As noted keep a journal to help you better identify what might be causing your issues. And then start adjusting your fueling plan or your workouts to lessen those yuck feelings.

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Nausea after running