Heartburn happens when stomach acid flows backward into your esophagus, the tube connecting your mouth to your stomach. About 20% of Americans experience this frequently enough to qualify as gastroesophageal reflux disease (GERD), defined as symptoms occurring two or more times per week. The cause is almost always a problem with the valve at the bottom of your esophagus, but what’s triggering that problem varies from person to person.
How Heartburn Actually Works
At the base of your esophagus sits a ring of muscle called the lower esophageal sphincter. When you swallow, this muscle relaxes to let food pass into your stomach, then tightens again to keep everything sealed. Heartburn occurs when this muscle relaxes at the wrong time or becomes too weak to close properly, allowing acid to wash upward into tissue that isn’t designed to handle it. That’s the burning sensation you feel in your chest and upper abdomen.
The esophagus has no protective lining against acid the way your stomach does. So even brief exposure to stomach acid creates irritation and pain. If acid reaches the back of your throat, you may also notice a sour taste or feel liquid rising up, which is called regurgitation.
Foods and Drinks That Trigger Reflux
Many common foods cause heartburn not because they’re acidic themselves, but because they relax that sphincter muscle or slow digestion in ways that increase pressure on it.
- Fatty foods directly relax the sphincter, weakening the barrier between your stomach and esophagus.
- Chocolate triggers the release of serotonin, which feels good but also relaxes the sphincter.
- Alcohol relaxes the sphincter and gives acid free access to the esophagus.
- Peppermint soothes muscle tissue throughout your digestive tract, including the sphincter you need to stay tight.
- Spicy foods contain capsaicin, which slows digestion and lets food sit in the stomach longer. Capsaicin also directly irritates esophageal tissue, making existing reflux feel worse.
- Carbonated drinks expand the stomach with gas, putting extra strain on the sphincter and encouraging acid to push through.
- Caffeine can be a trigger, especially when you’re consuming it multiple times throughout the day from coffee, tea, soda, or energy drinks.
If your heartburn seems random, keeping a simple food diary for a week or two often reveals a pattern. You don’t necessarily need to eliminate all of these. Most people find that one or two specific triggers are responsible for most of their episodes.
Medications That Cause Heartburn
If your heartburn started or worsened around the same time you began a new medication, the drug itself could be the problem. Some medications irritate the esophagus directly, while others weaken the sphincter muscle.
Common culprits that irritate the esophagus include ibuprofen, aspirin, certain antibiotics, iron supplements, and osteoporosis drugs like alendronate. These can cause a burning pain that mimics classic reflux.
Other medications weaken the sphincter or increase acid production. Blood pressure medications (particularly calcium channel blockers), opioid painkillers, sedatives, and tricyclic antidepressants all fall into this category. If you suspect a medication is behind your symptoms, talk to your prescriber about alternatives or timing adjustments rather than stopping on your own.
Hiatal Hernia and Structural Causes
Sometimes the issue is anatomical. A hiatal hernia occurs when the junction between your esophagus and stomach slides upward through the diaphragm, the flat muscle separating your chest from your abdomen. This displacement pulls on the muscles that normally help keep the sphincter closed, weakening their grip. The hernia also traps a small pocket of acid at the top of the stomach that can’t drain away normally, creating a reservoir of acid sitting right at the entrance to your esophagus.
Many people have small hiatal hernias and never know it. Larger ones tend to cause persistent heartburn that doesn’t respond well to dietary changes alone.
Pregnancy and Hormonal Changes
Heartburn is extremely common during pregnancy, and there are two reasons working together. First, rising progesterone levels relax smooth muscle throughout the body, including the esophageal sphincter. Progesterone also slows digestion, meaning food stays in the stomach longer and produces more acid. Second, as the uterus grows, it pushes upward against the stomach, physically forcing contents toward the esophagus. This is why heartburn tends to intensify in the third trimester even if you’ve changed nothing about your diet.
Habits That Make It Worse
Beyond specific foods, everyday habits play a surprisingly large role. Eating large meals stretches the stomach and increases pressure on the sphincter, much like carbonated drinks do. Lying down within two to three hours of eating removes gravity from the equation, making it far easier for acid to travel upward. Bending over after a meal has the same effect.
Being overweight increases abdominal pressure on the stomach constantly, not just after meals. Even modest weight loss can reduce heartburn frequency for people carrying extra weight around the midsection. Smoking also weakens the sphincter over time and reduces saliva production, which normally helps neutralize small amounts of acid in the esophagus.
Sleeping With Heartburn
Nighttime heartburn is particularly disruptive because lying flat eliminates the gravitational advantage that keeps acid in your stomach during the day. Two changes make a significant difference. Elevating the head of your bed by placing blocks or a wedge under the mattress (not just stacking pillows, which can bend you at the waist and make things worse) uses gravity to your advantage. Sleeping on your left side also helps. Sleeping on your right side tends to worsen symptoms for both GERD patients and people with occasional heartburn, including pregnant women. Flipping to your left side reliably reduces reflux episodes.
When Heartburn Becomes GERD
Occasional heartburn after a heavy meal is normal. When it happens twice a week or more, it crosses into GERD territory, and the concern shifts from discomfort to potential damage. Chronic acid exposure can inflame and erode the esophageal lining over time. Standard treatment typically starts with an eight-week course of acid-reducing medication. For people whose symptoms resolve and who don’t have complications, guidelines recommend trying to step down or stop the medication rather than staying on it indefinitely.
People with more serious esophageal damage or conditions like Barrett’s esophagus generally need longer-term treatment. If you’ve been on acid-reducing medication for more than a year without anyone reassessing whether you still need it, that conversation is worth having. Earlier concerns that long-term use of these medications might increase the risk of bone fractures, kidney disease, dementia, or heart attack have not held up under more rigorous study, though there does appear to be a modest increase in the risk of certain intestinal infections.
Heartburn vs. Heart Attack
Heartburn and heart attacks can feel remarkably similar. Even experienced doctors sometimes can’t distinguish them without testing. Typical heartburn produces a burning sensation in the chest, occurs after eating or when lying down, and improves with antacids. A heart attack is more likely to feel like pressure, tightness, or squeezing in the chest that spreads to the neck, jaw, or arms. It often comes with shortness of breath, cold sweat, sudden dizziness, or unusual fatigue.
Women are more likely than men to experience less obvious heart attack symptoms like jaw pain, back pain, nausea, or shortness of breath without the classic chest pressure. If your chest pain is new, severe, accompanied by any of those additional symptoms, or simply feels different from your usual heartburn, treat it as a potential emergency.