Acid Reflux When Running? 4 Causes + Helpful Tips To Prevent It

Running can be associated with uncomfortable sensations such as feeling out of breath, like your legs are heavy or on fire, and potentially feeling nauseous or like you need to run to the bathroom.

Although less common, some runners also experience acid reflux when running or what may be described as heartburn when running.

But, what causes heartburn when working out? Is it normal to experience acid reflux when working out? What can you do to prevent acid reflux when running?

In this article, we will discuss the symptoms of exercise-induced heartburn, common causes of heartburn or acid reflux when running, and tips to prevent heartburn when running or exercising.

We will cover the following: 

  • What Is Exercise-Induced Heartburn?
  • What Causes Acid Reflux When Running or Working Out?
  • Why Do I Get Heartburn When Running?
  • How to Prevent Acid Reflux When You Run

Let’s dive in! 

A person with acid reflux.

What Is Exercise-Induced Heartburn?

Exercise-induced acid reflux, or exercise-induced heartburn, is acid reflux (commonly described as “heartburn“) that occurs when working out as a result of the physical activity itself.

Because the contents of the stomach are highly acidic, the gastric juices that escape up into the esophagus during exercise can cause a burning sensation in the chest, which is experienced as “heartburn.“

Other symptoms of acid reflux when running or exercising include nausea, burping, a feeling of fullness, bloating or belly distention, a sore throat, a lump in the throat, coughing, or general stomach burning or discomfort.

What Causes Acid Reflux When Running or Working Out?

There are several factors that can contribute to experiencing acid reflux when running or heartburn while working out.

In general, acid reflux typically occurs when contents of your stomach, which includes partially digested food, stomach acid, and digestive enzymes, travel in the “wrong direction,“ meaning that these fluid and semi-solids travel upward towards the esophagus rather than downward through the digestive tract into the small intestines.

A runner with acid reflux.

Under normal and healthy conditions, the digestive tract is a one-way or one-direction pathway from the mouth down through the anus. 

Once partially-digested foods have passed through a certain region, they should not reverse course and travel back the opposite way.

However, in the case of acid reflux, the lower esophageal sphincter, commonly referred to as the LES, permits food and liquid to flow back up into the esophagus rather than sealing off the juncture tightly between the esophagus and the stomach.

The LES is a muscular band that encircles the end of the esophagus and should function as a one-way valve that prevents the backflow of the stomach contents into the esophagus.

However, the LES can become weak, or when it is relaxed, excess acidic stomach contents can travel up into the esophagus, causing heartburn while running or working out.

There are various risk factors for exercise-induced acid reflux, or acid reflux in general, including obesity, pregnancy, and overeating.

A person holding their stomach in pain.

Particularly in the case of obesity or pregnancy, excess pressure or fullness in the abdominal cavity, either due to the presence of a growing fetus, excess visceral fat, or a stomach packed with contents after a large meal, can force the semi-solid contents of the stomach back up into the esophagus. 

Note that although this will not necessarily cause acid reflux while running, lying down too soon after eating can also cause acid reflux. 

Therefore, if you are experiencing heartburn while working out doing exercises like supine bench press, abdominal or core exercises lying down, or yoga in the lying down position, you may experience acid reflux when working out if you have recently eaten.

Certain dietary choices and lifestyle habits can also increase the risk of heartburn while working out.

For example, studies suggest that caffeine, carbonated beverages, citrus fruits, tomatoes, other acidic foods, and tobacco or cigarette smoking can also increase the risk of acid reflux when running or, in general, as can certain medications, such as antibiotics.

A person sitting on a bench outside in pain.

Why Do I Get Heartburn When Running?

So, now let’s look more specifically at the question: “Why do I have heartburn while running?“

First, it’s important to note that if you experience nausea and heartburn while running, you are not alone.

Studies suggest that up to 83% of marathon runners complain about various GI symptoms that are associated with their running, and this might include bloating, gas, burping, nausea, stomach distention, and heartburn when running.

In addition to the aforementioned causes of acid reflux during exercise, here are some of the additional factors that can cause acid reflux when running:

#1: Running Too Soon After Eating

Typically, the most common cause of heartburn while running is running too soon after eating. 

A bowl of oatmeal and fruit.

Essentially, if you go running or start your workout too soon after eating, you will still have a lot of undigested food and digestive enzymes in your stomach when you begin exercising.

Particularly when you work out at a high intensity, the digestive system essentially shuts down in order to properly fuel your working muscles with oxygen rich-blood and nutrients.

Circulation patterns change to divert blood away from the stomach and digestive tract so that there is more to circulate to the muscles, lungs, and heart.

Because the blood flow to the digestive organ is so minimal while exercising, your stomach and intestines do not have the resources they need to carry out the normal digestive function, so digestion essentially ceases.

Therefore, any remaining undigested food in your stomach will sit around in a holding pattern until you have stopped running or working out and circulation to the stomach has resumed.

If there is still a lot of food in your stomach because you have gone running too soon after eating, the stomach contents can work their way back up the esophagus. 

#2: Jostling of the Stomach

Vigorous, high-impact exercise such as running causes mechanical jostling to the entire digestive tract, including the stomach.

Because the lower esophageal sphincter relaxes somewhat during physical activity, the jostling from the up-and-down movement and impact pounding as you run can allow the acidic gastric contents to sneak up through the LES and cause acid reflux when running.

A person on the couch with stomach pain.

#3: Increased Intra-Abdominal Pressure

In addition to mechanical jostling, another cause of exercise-induced heartburn is that exercise increases intra-abdominal pressure in and of itself.

When you exercise, especially when you are running at a high intensity, there is an increase in intra-abdominal pressure in your abdominal cavity,

This means that there is more pressure on the contents of the stomach.

As intra-abdominal pressure increases, the stomach contents and acidic digestive juices can force their way up through the LES into the esophagus, leading to acid reflux when you run.

So, why does this happen?

When you run or exercise, you are engaging your core muscles and simultaneously breathing with greater depth and force.

This causes the diaphragm to press down further into the abdominal space.

At the same time, the core muscles, such as the rectus abdominis, internal and external obliques, and especially the transversus abdominis (which is a deep core muscle that encircles your entire torso like a corset), contract more forcefully and rapidly, further decreasing the open space or volume in the abdominal cavity. 

Essentially, high-intensity running compresses the abdominal cavity and squeezes the organs in the abdomen, including the stomach.

This pressure can force the contents back up into your esophagus, leading to heartburn during exercise.

An energy gel.

#4: Eating the Wrong Foods Before Running

As mentioned, acidic foods, such as citrus, processed cheeses, coffee, orange juice, and soda, can increase the likelihood of experiencing acid reflux when running because these foods are acidic and can irritate the lining of the stomach.

This can cause a burning sensation experienced as heartburn during a workout.

How to Prevent Acid Reflux When You Run

Ultimately, to prevent acid reflux when running, try to be mindful of what you eat before you run and how long you wait after eating to run

Be sure that when eating a small snack, leave about 60 minutes before a run, and for a larger meal, leave at least 2-3 hours, depending on the amount of food and the length and intensity of the run.

Avoid trigger foods that can exacerbate the condition, such as tomato products, citrus fruits, and other acidic foods such as vinegar, fatty foods, alcohol, and coffee, particularly before running, though at all times in your diet, if possible.

If you are experiencing acid reflux or gastroesophageal reflux disease (GERD) when running that extends throughout most of the day, you should speak with your healthcare provider about potential treatment options.

There are medications and lifestyle modifications that can be helpful in alleviating the symptoms of GERD.

If you are experiencing heartburn when working out and want a potential option to quell nausea during exercise, check out our guide to the benefits of ginger chews here.

A pile of ginger chews.
Photo of author
Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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