Heartburn is a burning sensation in your chest caused by stomach acid flowing backward into your esophagus, the tube connecting your mouth to your stomach. It affects roughly 14% of adults worldwide, making it one of the most common digestive complaints. Despite the name, it 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, this muscle relaxes to let food pass into your stomach, then tightens again to keep acidic stomach contents from creeping back up. Under normal conditions, it stays firmly contracted.
Heartburn occurs when this valve relaxes at the wrong time. Your stomach naturally produces strong acid to break down food, and when that acid escapes upward into the esophagus, it irritates the lining, which isn’t built to handle it. The most common trigger for these unwanted relaxations is stomach distension: when your stomach stretches from a large meal or trapped gas, it sets off a nerve reflex that briefly opens the valve. This is why heartburn so often strikes after eating.
Common Triggers
Certain foods and habits are well-known culprits because they either weaken the valve muscle or increase acid production. High-fat meals, chocolate, mint, alcohol, and carbonated drinks all reduce the pressure that keeps the valve shut. Spicy foods, citrus fruits, tomatoes, onions, and garlic can irritate the esophageal lining directly or promote acid secretion. Coffee and other caffeinated beverages are frequent offenders too.
Volume matters as much as content. Large, high-calorie meals stretch the stomach more, making those unwanted valve relaxations more likely. Eating close to bedtime is a particularly effective recipe for heartburn because lying down removes gravity’s help in keeping acid where it belongs. Tight clothing around the waist, excess body weight, and smoking all increase pressure on the stomach or weaken the valve.
What Heartburn Feels Like
The classic symptom is a burning pain behind your breastbone that often moves upward toward the throat. It typically starts after eating, or when you lie down or bend over. You might also notice a sour or bitter taste in the back of your mouth, difficulty swallowing, or a feeling that food is stuck in your chest. Some people describe it as a warm, acidic sensation rather than outright pain.
Occasional heartburn after a heavy meal is normal and not a sign of a serious problem. When it happens more than twice a week or starts interfering with your daily life, it may indicate gastroesophageal reflux disease (GERD), a chronic condition where acid reflux causes ongoing symptoms or tissue damage.
Heartburn vs. Heart Attack
Because both produce chest discomfort, people sometimes confuse heartburn with a cardiac event. There are key differences. Heartburn produces a burning sensation that usually starts after eating or while lying down. A heart attack typically causes pressure, tightness, or a squeezing ache in the chest or arms that may spread to the neck, jaw, or back, and is often brought on by physical exertion rather than food.
That said, both can produce symptoms that come and go, and the overlap can be real. If your chest pain is accompanied by shortness of breath, cold sweats, lightheadedness, or pain radiating to your arm or jaw, treat it as a cardiac emergency.
Heartburn During Pregnancy
Heartburn affects 30 to 50% of pregnant women. Rising levels of progesterone relax smooth muscle throughout the body, including the valve at the base of the esophagus. As pregnancy progresses, the growing uterus also pushes upward on the stomach, adding physical pressure. These two forces together make the second and third trimesters prime time for reflux symptoms. For most women, heartburn resolves after delivery.
Over-the-Counter Relief Options
Three main categories of medication are available without a prescription, and they work at different speeds.
- Antacids (calcium carbonate products like Tums) neutralize acid that’s already in the stomach. They work the fastest, often within minutes, but relief is short-lived.
- H2 blockers (like famotidine) reduce the amount of acid your stomach produces. They take about an hour to kick in, but relief lasts 4 to 10 hours.
- Proton pump inhibitors (PPIs) (like omeprazole) block acid production more aggressively. They take 1 to 4 days to reach full effect, but provide the longest-lasting relief and are often used for persistent symptoms.
For occasional heartburn, antacids or an H2 blocker before a meal you know will be a trigger is a reasonable approach. PPIs are better suited to frequent, ongoing symptoms because of their delayed onset and stronger suppression.
Risks of Long-Term Acid Suppression
PPIs are effective, but using them continuously for months or years comes with trade-offs. Your stomach needs acid to absorb certain nutrients properly. Long-term PPI use has been linked to deficiencies in vitamin B12, magnesium, calcium, and iron. A large study found that two or more years of PPI use significantly increased the risk of B12 deficiency, particularly at higher doses. A meta-analysis of over 109,000 patients showed PPI users had a 43% higher risk of low magnesium levels.
Chronic use has also been associated with increased fracture risk. A review of 32 studies found higher rates of hip, spine, and other fractures among PPI users, likely related to impaired calcium absorption and effects on bone metabolism. The overall increase in fracture risk is estimated at about 28%. These risks don’t mean you should avoid PPIs if you need them, but they’re worth weighing if you’ve been taking them indefinitely out of habit rather than necessity.
Lifestyle Changes That Help
Simple adjustments can reduce heartburn significantly, sometimes enough to avoid medication entirely. Eating smaller meals takes pressure off the stomach valve. Waiting at least two to three hours after eating before lying down gives your stomach time to empty. Avoiding your personal trigger foods (fatty meals, alcohol, chocolate, and carbonated drinks are common starting points) reduces acid exposure.
For nighttime symptoms, elevating the head of your bed by about 20 centimeters (roughly 8 inches) using blocks under the bed frame has been shown to reduce overnight acid exposure. Stacking pillows is less effective because it bends you at the waist rather than creating a gradual incline. Sleeping on your left side also helps, since it positions the stomach below the esophagus.
Losing weight, if you carry extra pounds around your midsection, reduces the abdominal pressure that pushes acid upward. Wearing loose-fitting clothing around the waist and quitting smoking both contribute to keeping the esophageal valve functioning properly.
When Heartburn Becomes a Bigger Problem
Chronic, untreated acid reflux can damage the esophageal lining over time. Repeated acid exposure may cause inflammation, ulcers, or narrowing of the esophagus that makes swallowing difficult. In some cases, the cells lining the lower esophagus change in response to ongoing acid injury, a condition called Barrett’s esophagus.
Barrett’s esophagus itself is not cancer, but it does carry an elevated risk. For people with Barrett’s who have no precancerous cell changes, the annual risk of developing esophageal cancer is roughly 0.1 to 0.4%. That risk climbs to about 1% per year when early precancerous changes are present, and above 5% per year with more advanced changes. These numbers are small in absolute terms, but they underscore why persistent reflux symptoms are worth addressing rather than simply tolerating.