Acid reflux is stomach acid flowing backward into the esophagus, the muscular tube connecting your mouth to your stomach. It causes a burning sensation in your chest or upper stomach, and you may taste something sour at the back of your throat. Nearly everyone experiences it occasionally, but when it becomes frequent or causes damage, it crosses into a chronic condition called GERD. Globally, about 826 million people deal with GERD, making it one of the most common digestive problems in the world.
How Acid Reflux Works
At the bottom of your esophagus sits a ring of muscle called the lower esophageal sphincter (LES). It opens to let food into your stomach, then closes to keep stomach contents from coming back up. Acid reflux happens when this valve doesn’t close properly or relaxes at the wrong time, letting acidic digestive juices escape upward.
Two main patterns of valve dysfunction drive most reflux. The more common one involves the sphincter relaxing too often when it shouldn’t. The second is a sphincter that’s simply too weak to stay closed, though this appears to be less common than doctors once thought. In both cases, the root problem is usually faulty nerve signaling to the muscle rather than a damaged muscle itself. A hiatal hernia, where part of the stomach pushes up through the diaphragm, can worsen things by pulling the sphincter out of position.
What Acid Reflux Feels Like
The signature symptom is heartburn: a burning sensation behind your breastbone that often worsens after eating, lying down, or bending over. Some people feel it more like a burning stomach pain, similar to indigestion. Others experience chest pain that doesn’t feel like burning at all, which can be alarming because it mimics heart-related pain. You may also notice a sour or bitter taste as stomach contents wash up into the back of your throat.
Not all reflux announces itself so clearly. A form called laryngopharyngeal reflux, or “silent reflux,” sends acid all the way up into the throat without causing typical heartburn. Instead, you might notice chronic hoarseness, a persistent feeling of something stuck in your throat, frequent throat clearing, or a lingering cough. If you have chronic hoarseness, there’s roughly a 50% chance silent reflux is the cause. Over time, acid reaching the throat can inflame the voice box, and tiny acid particles can even slip into the airways during sleep, triggering bronchial inflammation or respiratory infections.
Occasional Reflux vs. GERD
A bout of heartburn after a heavy meal is normal. GERD is the diagnosis when reflux becomes a recurring pattern that either causes repeated symptoms or starts damaging tissue. There’s no single test that draws the line. Doctors typically start by reviewing your symptoms and medical history. If lifestyle changes and over-the-counter medications don’t help, they may order tests.
The most definitive test is esophageal pH monitoring, where a thin tube or a small wireless probe placed in your esophagus measures acid levels continuously for 24 to 96 hours. This captures exactly how often acid enters your esophagus and how long it stays there. An upper endoscopy, where a tiny camera examines the lining of your esophagus, can reveal inflammation, ulcers, or tissue changes caused by chronic exposure to acid.
What Chronic Reflux Does to Your Body
When acid repeatedly contacts the esophageal lining, it causes inflammation called esophagitis. This can feel like persistent heartburn, chest pain, or a sore throat, and it may make swallowing uncomfortable. Over time, the inflammation can lead to scarring that narrows the esophagus, making it physically harder for food to pass through. Open sores called peptic ulcers can also develop in the damaged tissue.
The more serious long-term risk is Barrett’s esophagus, a condition where the cells lining the lower esophagus change to resemble intestinal tissue in response to chronic acid exposure. Between 10% and 15% of people with GERD develop Barrett’s. It matters because these altered cells carry a small risk of progressing to esophageal cancer, roughly half a percent per year. That risk is low enough that most people with Barrett’s never develop cancer, but it’s high enough that doctors monitor the condition with periodic endoscopies.
Long-term vocal inflammation from silent reflux is a separate concern and a risk factor for laryngeal cancer, though this outcome is uncommon.
How Acid Reflux Is Treated
Treatment follows a ladder. The first rung is antacids, which neutralize acid already in the stomach and provide quick but short-lived relief. The next step up is a class of medications that block one of the chemical signals telling your stomach to produce acid. These work within about an hour, can be taken as needed, and are available over the counter. The catch is that your body adapts to them quickly, sometimes within three days, making them less effective for daily long-term use.
The strongest widely used medications are proton pump inhibitors (PPIs), which shut down the acid-producing pumps in the stomach lining. They’re more potent and longer-lasting, but they need to be taken daily for four to eight weeks to reach full effect. The general guidance is to use the lowest effective dose for the shortest time that controls your symptoms, then reassess.
Lifestyle Changes That Help
Medications work better when paired with physical and dietary adjustments. Eating smaller meals, avoiding food within two to three hours of bedtime, and limiting known triggers (fatty foods, alcohol, coffee, chocolate, citrus, and tomato-based foods are common ones) all reduce the amount of acid available to reflux.
Sleep position makes a measurable difference. Elevating your upper body with a wedge pillow keeps gravity working against the backflow. Research from Harvard Health found that sleeping on your left side clears acid from the esophagus significantly faster than sleeping on your back or right side. Combining left-side sleeping with upper-body elevation is one of the most effective non-medication strategies for nighttime reflux.
Weight loss also helps if you’re carrying extra weight around the midsection, because abdominal pressure pushes stomach contents upward. Tight clothing around the waist can do the same thing on a smaller scale. Quitting smoking matters too, since nicotine relaxes the lower esophageal sphincter.