Heartburn is a burning sensation in your chest caused by stomach acid flowing backward into your esophagus, the tube that connects your mouth to your stomach. It affects a large portion of the population, with studies estimating that 18 to 28% of adults in North America experience it regularly. Despite the name, heartburn has nothing to do with your heart.
What Happens Inside Your Body
At the bottom of your esophagus sits a ring of muscle that acts like a one-way valve. When you swallow, it opens to let food into your stomach, then closes to keep stomach acid where it belongs. Heartburn happens when this valve either relaxes at the wrong time or doesn’t close tightly enough, allowing acid to wash up into the esophagus.
Two main patterns cause this valve to malfunction: it relaxes too frequently on its own, or its resting pressure is too weak to hold acid back. The problem is primarily one of nerve signaling rather than muscle damage, though both can play a role. A hiatal hernia, where part of the stomach pushes up through the diaphragm, can also impair the valve’s ability to seal properly.
Your stomach lining is built to handle acid. Your esophagus is not. When acid repeatedly contacts the esophageal lining, it causes the irritation and burning you feel as heartburn.
What Heartburn Feels Like
The hallmark symptom is a burning sensation behind your breastbone that can extend up toward your throat. It typically shows up after eating, or when you lie down or bend over. You may notice a sour or bitter taste in your mouth, especially at night, sometimes with a small amount of stomach contents rising into the back of your throat. Heartburn can also wake you from sleep if you’ve eaten within a couple of hours of going to bed.
Antacids usually bring quick relief, which is one way to distinguish heartburn from something more serious. If the burning doesn’t respond to antacids, or if it’s accompanied by chest pressure, shortness of breath, jaw or arm pain, or sweating, those are signs of a potential cardiac event, not heartburn.
Common Triggers
Certain foods directly weaken that muscular valve at the base of your esophagus. Coffee, both regular and decaf, relaxes it. So do fatty, fried, and spicy foods, which also slow stomach emptying, meaning acid sits in your stomach longer with more opportunity to splash upward. Large meals create the same problem by stretching the stomach and putting pressure on the valve.
Timing matters as much as what you eat. Lying down within two to three hours of a meal is one of the most reliable heartburn triggers because gravity is no longer helping keep acid in your stomach. Tight clothing around the waist, excess body weight, and smoking can all increase abdominal pressure or weaken the valve further.
Heartburn vs. GERD
Everyone gets heartburn occasionally. It becomes a medical condition called gastroesophageal reflux disease (GERD) when acid reflux causes symptoms two or more times a week, or when it starts damaging the tissue lining your esophagus. If you find yourself reaching for over-the-counter heartburn medication twice a week or more, that frequency alone suggests GERD rather than occasional reflux.
GERD left untreated over years can lead to a condition called Barrett’s esophagus, where the normal flat, pink lining of the esophagus thickens and changes in response to chronic acid exposure. People with Barrett’s esophagus have a slightly increased risk of esophageal cancer, though most will never develop it. The concern is enough, however, that doctors monitor Barrett’s patients regularly.
Warning Signs Worth Noting
Most heartburn is uncomfortable but harmless. Certain symptoms alongside heartburn, though, point to complications or other conditions that need evaluation:
- Difficulty swallowing or pain while swallowing, which can signal narrowing of the esophagus from chronic inflammation
- Persistent vomiting or loss of appetite
- Unexplained weight loss
- Vomit that contains blood or looks like coffee grounds
- Stool that is black, tarry, or contains visible blood, which suggests bleeding in the digestive tract
How Over-the-Counter Treatments Work
Three classes of medication are available without a prescription, and they work differently enough that choosing the right one depends on your situation.
Antacids neutralize acid that’s already in your stomach. They work the fastest of the three options, providing relief within minutes. The tradeoff is that the effect wears off relatively quickly, making them best for occasional, predictable episodes.
H2 blockers take a different approach. Instead of neutralizing existing acid, they block one of the chemical signals that tells your stomach to produce acid in the first place. They take about an hour to kick in but provide relief lasting four to ten hours. They’re a good middle ground if you get heartburn frequently but not daily.
Proton pump inhibitors (PPIs) are the most powerful option, suppressing acid production more aggressively than H2 blockers. The catch is they take one to four days to reach full effect, so they’re not useful for immediate relief. Their effects last much longer, making them better suited for people dealing with symptoms most days of the week.
Lifestyle Changes That Help
Medications aside, a few practical adjustments can reduce how often heartburn strikes. Eating smaller meals takes pressure off the valve between your stomach and esophagus. Staying upright for at least two to three hours after eating gives gravity time to keep acid in your stomach before you lie down.
Sleep position makes a measurable difference. Lying on your left side places the stomach below the esophagus, so acid is less likely to travel upward. Right-side sleeping does the opposite, positioning the stomach above the esophageal opening. Elevating the head of your bed by a few inches (using a wedge or bed risers, not just extra pillows) also helps by keeping your upper body on an incline throughout the night.
Losing even a moderate amount of weight, if you carry extra pounds around the midsection, reduces abdominal pressure on the valve. Avoiding tight belts and waistbands works on the same principle. These changes won’t eliminate severe GERD, but for mild to moderate heartburn, they can be enough to make medication unnecessary.