Gastroesophageal (pronounced: gas-tro-ih-sah-fuh-jee-ul) reflux disease is a condition in which acid from the stomach regurgitates or refluxes into the esophagus. (The muscular tube that connects the mouth to the stomach is called the esophagus). Simply put, in this disorder, liquid from the stomach starts to flow backwards into the esophagus. This liquid contains acid and pepsin (pepsin is an enzyme that aids the digestion of protein within the stomach). It may also contain some bile.

The most harmful constituent among these is the acid. In rare cases it can even inflame the lining of the esophagus. The more common symptoms, however, are heartburn, strictures, difficulty in swallowing and chest pain. Patients may experience one or a combination of these symptoms.

GERD, once it happens, usually lasts a lifetime. If the esophagus is injured, then the condition is chronic. Symptoms do subside with regular treatment, and tend to disappear temporarily when the treatment is terminated. However, problems will resurface after a few months and treatment will have to be resumed.

It is normal for some amount of the stomach's liquids to reflux into the esophagus in all of us. In GERD patients however, the liquid contains a greater proportion of acid and takes longer to go back into the stomach. Therefore, while occasional instances of heartburn are considered normal, persons who experience it more than once a week are at greater risk of developing GERD. Chances of developing GERD are heightened if one already suffers from hiatal hernia.

The good news is that the body does have its own mechanisms to ease the symptoms. For instance, most reflux occurs during the day, when we are upright and therefore making gravity work for us. In an upright position, refluxed liquid flows back into the stomach at a faster rate. When awake, we swallow more often, each time forcing the reflux back into the stomach. Additionally, the saliva produced in the mouth contains bicarbonate, which neutralizes acid. With each swallow, as this saliva travels down the esophagus, it neutralizes the leftover acid after swallowing and gravity have done most of the work.

However, at night, when we are in a prostrate position and asleep, gravity does not work, and swallowing stops. Therefore, reflux at night is likely to act detrimentally on the esophagus because it stays there longer.