What Is Acid Reflux (GERD)?

It is past midnight, you ate late, and now a burning feeling is creeping up behind your breastbone, worse since you lay down. Most people call that heartburn — and a handful of stubborn myths tend to come with it. Sorting those myths from the facts is a good way to understand what's actually going on. The short video above, "Understanding Heartburn" (about a minute and a half), covers the basics of acid reflux, and the guide below builds on it.

Myth: heartburn means something is wrong with your heart

Fact: despite the name, heartburn has nothing to do with the heart. The burn comes from your oesophagus — the tube carrying food from your mouth to your stomach. At the bottom of that tube sits a ring of muscle that is meant to open for food and then close again. When it relaxes at the wrong time or doesn't close fully, stomach acid can splash upward into a tube that was never built to handle it, and that splash is what burns. Occasional reflux after a big, late meal is common and usually settles. When it happens regularly — typically, when troublesome symptoms keep coming back week after week — clinicians call it gastroesophageal reflux disease, or GERD. The difference matters: an occasional burn is a nuisance, while ongoing reflux deserves a proper look, because acid bathing the oesophagus over time can irritate and inflame its lining.

Myth: if it burns, you must be making too much acid

Fact: most people with reflux make a normal amount of acid — the problem is where the acid ends up, not how much of it there is. That is why everyday patterns matter so much. Lying flat removes gravity's help. A very full stomach puts pressure on that muscular ring. Large evening meals, lying down soon after eating, and carrying extra weight around the middle can all make reflux more likely, and many people notice particular foods or drinks set theirs off. Keeping a simple note of when the burning shows up — after which meals, at what time, in what position — often reveals a pattern your clinician can work with, and it is more useful than guessing.

Myth: nothing can be done except put up with it

Fact: reflux care usually starts with the unglamorous basics — smaller evening meals, staying upright for a while after eating, raising the head of the bed if nights are the worst time, and easing off your personal triggers. When symptoms persist, doctors can prescribe medicines that reduce how much acid the stomach makes, giving the oesophagus a chance to settle; these are taken under medical guidance rather than improvised indefinitely on your own. If symptoms keep returning, or if there are warning signs — difficulty swallowing, food sticking, unexplained weight loss, vomiting, or black stools — your doctor may suggest looking inside with a camera test, explained in our guide to what an endoscopy shows. For a smaller group of people whose reflux is driven by a weak valve and stays troublesome despite treatment, surgery to reinforce that valve is sometimes discussed; the site's video of a laparoscopic Nissen fundoplication (about two and a half minutes) shows the operation most often meant by that.

One caution sits above all the myths: chest discomfort should never be assumed to be heartburn. If chest pain is heavy, spreading, comes with breathlessness or sweating, or simply feels wrong, treat it as an emergency and seek help immediately — that call is never an overreaction.

MedicalVideos.com has published trusted medical videos since 2007. The site was founded by Dr. Mohamed Ibrahim, MD, PhD — physician and researcher.

Frequently Asked Questions

What is the difference between acid reflux, heartburn, and GERD?
Acid reflux is the event — stomach acid flowing back into the oesophagus. Heartburn is the burning feeling that event can cause. GERD is the longer-term condition in which reflux keeps happening and produces troublesome symptoms or irritation.

Why is my reflux worse at night?
Lying flat removes gravity's help in keeping stomach contents down, and a late, large meal leaves the stomach full at bedtime. Staying upright after eating and raising the head of the bed can help some people.

Can acid reflux damage the oesophagus?
It can. Repeated acid exposure can irritate and inflame the lining over time, which is one reason frequent, persistent reflux should be assessed rather than simply endured.

When should heartburn be checked urgently?
Chest pain that is heavy or spreading, or that comes with breathlessness, sweating, or pain in the arm or jaw, needs emergency help — do not assume it is heartburn. Difficulty swallowing, food sticking, vomiting, black stools, or unexplained weight loss should also be checked promptly.

Educational only — this article is general information about acid reflux and GERD, not medical advice and not a diagnosis. If you have frequent heartburn or any of the warning signs described above, discuss it with your own clinician.