What Causes Heartburn?

Instructor: Artem Cheprasov
This lesson will define heartburn and explain the various causes that may predispose a person to having heartburn. We will also consider the physiological reason that heartburn occurs.

Heartburn and the Heart

Have you heard of heartburn? Did you know that it has absolutely nothing to do with the heart? If you said 'yes' you are correct. But if you said 'no' you're also correct. Heartburn itself is not a problem with the heart. However, some of the symptoms of a heart attack can be mistaken for heartburn. So, heartburn and heart attack are somewhat related, depending on the particulars of a situation.

This lesson, however, doesn't address the heart attack part. Instead, we're going to discuss what heartburn is and what actually causes it.

What is Heartburn?

Heartburn is not a disease, disorder, syndrome, or condition. It's a symptom. A symptom is a subjective experience that only you can say for sure you're experiencing and to what extent. This is different from a sign, which is something that an independent observer can detect and objectively measure.

This symptom, heartburn, includes a burning sensation that is centered on your chest, but can also radiate outwards uncomfortably. This burning pain can be made worse if you bend over or lie down.

What Causes Heartburn?

So why do you get heartburn? It boils down to acid. Think about how acid burns through metal in a cartoon on TV. Well, acid burns your tissues too. This includes the tissues of the esophagus, the food tube. The esophagus is the long muscular tube that passes the food you swallow down into your stomach.

Note the location of the esophagus and stomach
Digestive tract

As food moves down the esophagus, it reaches the place where the esophagus meets the stomach. This strong and muscular connection point is called the lower esophageal sphincter (LES) . It's a band of strong muscles that clenches around the place where the esophagus and stomach meet up, much like a fist around a hose. When it clenches tight, nothing passes through this point.

Normally, when food passes from the esophagus into the stomach, the LES relaxes. Otherwise, food wouldn't get into the stomach! Once the food has dropped into the stomach, the LES closes again. However, various conditions such as obesity may cause the LES to abnormally relax or weaken. If this happens, stomach acid may reflux (go back up) into the esophagus.

Now, you know that acid burns. Well, stomach acid burns too! It doesn't burn the stomach because the stomach has a protective layer that coats its inner walls and renders it immune to the stomach acid. But the esophagus has no such thing! So, the acid chemically burns and irritates the esophagus. This is what causes all that pain in heartburn!

Various things, other than obesity, can predispose one to heartburn or worsen the degree of heartburn. These include:

  • Eating large meals, which can expand the stomach so much that the LES opens inappropriately.
  • Lying down soon after eating, which may cause the LES to open.
  • Drugs such as alcohol, morphine, and others may relax the LES.
  • Greasy foods can relax the LES

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