What is a one-sentence summary of the following article?
Gastroesophageal Reflux Disorder, also known as GERD or acid reflux, is a disorder is which contents from your stomach and intestines enter your esophagus. The acid from the stomach migrates upwards past your lower esophagus, causing a burning pain and, at times, actual erosion of the tissue of the esophagus. Approximately 25 to 35% of Americans are affected acid reflux.  It is uncomfortable and quite painful in some cases.   The discomfort can be assessed on a spectrum from just mild burning to a severe burning chest pain, mimicking a heart attack. The pain of acid reflux is brought on by the gastric fluid, which has a very low acidic pH. It migrates up the esophagus and finds its way into an environment where it doesn’t belong and is not intended to be, such as your esophagus. The migration of gastric fluid that causes acid reflux can be caused by a loose lower esophageal sphincter (LES). It can also be due to gravity, which can take effect if you lie down right after a meal. Acid reflux can also be caused by overeating and applying too much pressure to the LES, forcing the stomach contents back past the sphincter. Other situations that may cause acid reflux are smoking, obesity, high intake of sodium, low intake of dietary fiber, limited physical exercise, and taking certain medications. There are multiple underlying conditions that can cause or be caused by acid reflux. Other conditions that can lead to acid reflux are pregnancy and a hiatal hernia, which is where a hole in the diaphragm allows the upper portion of the stomach to enter the chest cavity.  Acid reflux can cause other conditions, such as a condition called Barrett’s Esophagus. Ask your doctor if you think your acid reflux has an underlying conditional cause or if you think it is causing more serious problems.

Summary:
Understand acid reflux. Recognize the causes. Be aware of underlying conditions.