Heartburn is most often a sign that stomach acid is flowing backward into your esophagus, the tube connecting your mouth to your stomach. When this happens occasionally, it usually points to something temporary like a heavy meal, a trigger food, or lying down too soon after eating. When it happens twice a week or more, it typically signals a chronic condition called gastroesophageal reflux disease (GERD). But heartburn can also be a sign of several other conditions, some harmless and some that need attention.
How Acid Reflux Actually Happens
At the bottom of your esophagus sits a ring of muscle that opens to let food into your stomach and closes to keep acid from coming back up. Heartburn happens when this muscle doesn’t do its job properly. Two main patterns of dysfunction cause the problem: the muscle relaxes at the wrong times, or its resting pressure is too weak to form a good seal. Both patterns appear to stem primarily from faulty nerve signaling to the muscle, though the muscle itself can also weaken over time.
The diaphragm, the sheet of muscle separating your chest from your abdomen, also plays a supporting role. It wraps around the base of the esophagus and provides extra squeeze to keep acid where it belongs. When that backup system is compromised, reflux becomes more likely.
GERD: The Most Common Underlying Condition
If heartburn shows up two or more times a week, that pattern meets the clinical threshold for GERD. The distinction matters because chronic acid exposure can damage the lining of your esophagus over time, causing narrowing, erosions, or precancerous cellular changes. These complications don’t always cause additional symptoms, which is why frequency alone is an important signal.
A small percentage of people with long-standing GERD develop a condition called Barrett’s esophagus, where the cells lining the lower esophagus change to a type not normally found there. Barrett’s is considered a precursor to esophageal cancer, though the actual progression rate is low, roughly 0.3% of Barrett’s patients per year. The risk is highest in people who’ve had frequent, untreated reflux for many years.
Hiatal Hernia
A hiatal hernia occurs when the upper part of your stomach pushes up through the opening in your diaphragm. This weakens the natural barrier that keeps acid in your stomach, making reflux significantly easier. Not everyone with a hiatal hernia gets heartburn, and not everyone with heartburn has a hiatal hernia, but the two overlap frequently. Hiatal hernias are more common as you age and in people who are overweight.
Pregnancy
Heartburn that starts during pregnancy is extremely common, typically appearing in the second or third trimester. Rising progesterone levels relax the muscular valve at the top of the stomach, allowing acid to flow upward more easily. As the uterus grows, it also puts physical pressure on the stomach. This type of heartburn usually resolves after delivery, though it can be persistent and uncomfortable in the meantime.
Medications That Trigger Heartburn
Some medications cause heartburn by relaxing the esophageal valve. These include certain blood pressure drugs (calcium channel blockers, ACE inhibitors, nitrates), sedatives, opioid pain medications, some antidepressants, and medications for overactive bladder. Even progesterone supplements can contribute.
Other medications cause heartburn-like pain by directly irritating the esophageal lining. Common culprits include ibuprofen and aspirin, certain antibiotics, iron supplements, and bisphosphonates (used for osteoporosis). If your heartburn started around the same time as a new medication, that connection is worth exploring.
Eosinophilic Esophagitis
This condition mimics GERD closely enough that it’s often mistaken for it, sometimes for years. Eosinophilic esophagitis is an allergic or immune-driven inflammation of the esophagus. The biggest clue is that standard acid-reducing medications don’t help. It’s more common in younger men and in people with allergies, asthma, or eczema. Other warning signs include difficulty swallowing, food getting stuck in your throat, or unintended weight loss. Diagnosis requires a biopsy during an endoscopy, which reveals a specific type of immune cell buildup in the esophageal tissue.
Silent Reflux
Not all reflux causes the classic burning sensation. Laryngopharyngeal reflux, often called “silent reflux,” happens when stomach acid reaches the throat and voice box rather than just the lower esophagus. Instead of heartburn, you might notice chronic throat clearing, a persistent cough, hoarseness, a feeling of something stuck in your throat, excessive mucus, or recurring sore throats. Some people develop new or worsening asthma symptoms. Because these don’t feel like typical heartburn, silent reflux often goes undiagnosed or gets attributed to allergies or sinus problems.
Heartburn vs. Heart Attack
The overlap between heartburn and cardiac chest pain is real and well-documented. Even experienced physicians can’t always distinguish them based on symptoms alone. Classic heartburn tends to produce a burning sensation in the chest, worsens after eating or when lying down, and improves with antacids. It often comes with a sour taste or a small amount of liquid rising in the back of your throat.
Heart attack pain is more commonly described as pressure, tightness, or squeezing in the chest or arms that may radiate to the neck, jaw, or back. It can be accompanied by shortness of breath, cold sweats, sudden dizziness, or unusual fatigue. Women are more likely to experience the less typical symptoms like jaw pain, back pain, and nausea rather than the crushing chest pain people associate with heart attacks.
The critical point is that a heart attack can cause what feels like heartburn or indigestion, and the pain doesn’t have to be severe or long-lasting to be a warning sign. Chest pain with shortness of breath, sweating, or lightheadedness warrants immediate medical attention regardless of whether it “feels like” heartburn.
Signs That Heartburn Needs Further Evaluation
Occasional heartburn after a large meal or a glass of wine is common and rarely signals anything serious. But certain patterns suggest something beyond routine reflux. Difficulty swallowing is one of the most important, as it can indicate narrowing of the esophagus, eosinophilic esophagitis, or other structural changes. Heartburn that doesn’t respond to over-the-counter acid reducers, especially after several weeks, is another signal that the underlying cause may be something other than straightforward GERD.
Unintentional weight loss, vomiting, or pain that changes in character or intensity also deserve attention. If you’ve been using over-the-counter antacids more than twice a week on a regular basis, that frequency alone suggests you’d benefit from a more specific diagnosis.