Why Do I Feel Nauseous After Running?

Updated:

Nothing ruins a good run like feeling nauseous after you’ve finished! This uncomfortable experience is more common than you may think. If this has affected you, you’re not alone.

You can treat it as it happens, but figuring out the reason behind your nausea is the key to stopping it.

Read this article to find out the many potential causes for post-run nausea and learn how to get rid of it.

Is It Normal to Feel Nauseous After a Run?

Feeling nauseous after exercise is not uncommon. It happens more often in long-distance and endurance athletes but can happen to any runner anytime.

What Causes Nausea After Running?

Many different things can cause post-run nausea. Here are the most common reasons you might be experiencing this.

You Ate Less Than an Hour Before Your Run

If you head out for a run less than an hour after your last meal, the running motion may cause the food to move around in your stomach before it begins to digest. This can lead to intense and sudden nausea and possibly vomiting.

If you must eat within an hour of your run, go for something light that takes longer to digest. A banana or a slice of toast with peanut butter are good options. Any meal larger than that should be eaten at least 90 minutes to 2 hours before you run.

Not Eating Enough Food

If you head out to run but haven’t eaten enough, you may also be at risk of nausea. In this case, your body won’t have the fuel it needs to perform properly, which can lead to several different symptoms, including nausea.

Eating Too Much

On the opposite end of the spectrum, if you eat too much, you may feel too full when you set out for a run. This can lead to discomfort and you might feel your pace and run are affected.

Eating the Wrong Foods

Even if you do eat the right amount, choosing the wrong foods can wreak havoc on your stomach. You’ll want to choose foods that are more bland and avoid things like:

  • Acidic foods, which can irritate the stomach lining.
  • Dairy can begin to ferment in the stomach, causing gas and pain.
  • Fatty or oily foods, which are rich and can aggravate the stomach.

Dehydration

Being dehydrated can also cause nausea. You should drink around 4 to 6 ounces every 20 minutes. It’s also important not to gulp it down, or it can slosh around your stomach and make you feel worse.

Electrolyte imbalance could also come into play here. If your run is longer than an hour, you’ll need to consume an electrolyte tablet to replenish any electrolytes you lose in your sweat.

Intense or Prolonged Exercise

Overexerting yourself can cause the muscles in the abdomen to spasm as the pressure in the abdomen increases, leading to nausea. This is more common during high-intensity workouts.

Pushing yourself too hard can have negative effects beyond nausea, so always taking it slow when increasing your workload is important.

Gastrointestinal Issues

Once you start exercising, the body sends blood to the extremities and the muscles for performance, drawing it away from the digestive system. This can slow down the digestive system, leading to the feeling of fullness and possibly cramping and nausea.

Other unpleasant gastrointestinal issues may include bloating, excessive gassiness, acid reflux or heartburn, and gastroparesis—a condition in which the stomach doesn’t empty properly.

Running in Heat and Humidity

When it’s hot, you’re more likely to dehydrate quickly. However, you may lose fluid faster in humid weather, even if it’s not hot.

In hot or humid weather, it’s a good idea to reduce your workout intensity and duration so you don’t end up feeling nauseous due to dehydration or potentially overdoing it.

Your Running Fuel Options

If you’ve been experimenting with new fuel options, they could cause nausea during and after a run.

In some cases, the sugar content of a sports drink or energy chew may cause your stomach to react badly. In other cases, the texture of an energy gel could be to blame.

Drinking Coffee or Taking a Caffeine Supplement

Coffee can increase the production of stomach acid, which is an unpleasant effect when your body is diverting blood away from the digestive system. If you drink coffee before your run or take a caffeine supplement, you might have an adverse effect.

Medication

Some types of medication may increase your chance of becoming nauseous. This might be increased when you pair them with something like an energy gel that could exacerbate the feeling.

How to Prevent Nausea Before Running

If you’re feeling nauseous before your run, taking a break for that day might be a good idea. But if you’re feeling good, you can head out on the run—just take steps to prevent nausea during your run.

Stay Hydrated

Staying properly hydrated will prevent the symptoms of dehydration. This is fundamental and should be done regardless of whether you struggle with nausea or not!

Find an easy way to carry your water, or create your route to go past a water fountain. You should drink 4 to 6 ounces every 20 minutes or so, with an electrolyte tablet for every hour you run.

Optimize Your Pre-Run Nutrition

Get your foot choices and food timing right. Choosing healthy, light, nutrient-filled foods will fuel you for the run, and eating them 90 minutes to 2 hours before you run will reduce the potential issue of having food in your stomach while you’re running.

Avoid Eating High-Fat and High-Fiber Foods

Foods that are high in fat and fiber can upset the stomach. Avoid them if possible. It’s also a good idea to take in minimal amounts of protein, as it digests slowly and can remain in the stomach for a long time. You should also avoid acidic foods and drinks.

Manage Stress and Anxiety

Stress and anxiety can cause the stomach to feel like it’s in knots! If this could be your issue, it’s in your best interest to reduce stressors in your outside-of-running life. These things can affect your performance while you’re running.

Warm Up Properly

Warming up will get the muscles ready for action. It helps the blood to get flowing, bringing oxygen and nutrients to organs and muscles throughout the body.

What to Do if You Get Nauseous While Running?

What happens if you experience nausea during your run? These tips will help you manage it while running.

Stop Running

This makes sense. Don’t continue to run and jostle your food around if you’re feeling like you might throw up. Slow down and walk for a while, focusing on your breathing as you allow your body to relax.

Take Deep Breaths and Relax

Deep breathing can help to settle your stomach. While you’re walking, work on taking deep, even breaths. Inhale through your nose and exhale through your mouth.

Try to breathe right down to your belly, allowing it to expand as you inhale. This may take some practice, but it’s worth practicing. Focusing on your breathing can also help your body to relax, like a form of meditation.

Sip on Water

Whatever you do, don’t gulp down water! Sip lightly on water as you walk and breathe deeply. Taking in too much will worsen the problem, but sipping lightly can alleviate symptoms of dehydration and give you something else to focus on as well.

Suck on a Peppermint or Ginger Sweet

Both mint and ginger are said to soothe upset stomachs. If you’re already wearing a running belt, stick a few ginger sweets or peppermints into it with your energy chews.

When you start to feel nauseous, slow down to a walk and chew or suck on a sweet. It’s a good idea not to do this while you’re running—walking is a safer option until your stomach has settled.

Give Your Stomach Some Time to Settle

Don’t expect your stomach to settle immediately. Give it a few minutes to come back to its normal self, and wait it out until it’s eased. Trying to push through nausea and discomfort can make it worse, and may put you at risk of vomiting.

Photo of author

AUTHOR

Ben is an avid road and trail runner, and has completed multiple marathons and ultras. A former running store owner, he now shares his knowledge and experience writing these articles.