What Is Heartburn? Symptoms, Triggers and Treatments

Heartburn is a burning sensation in the chest caused by stomach acid flowing backward into the esophagus, the tube connecting your mouth to your stomach. It happens when the muscular valve at the bottom of that tube relaxes at the wrong time or stays too weak to keep acid where it belongs. Most people experience it occasionally after a heavy meal, but when it becomes frequent, it signals a condition called gastroesophageal reflux disease, or GERD. The feeling can range from a mild warm discomfort behind the breastbone to a sharp pain that radiates toward the throat, and it can be surprisingly tricky to distinguish from more serious problems.

Why Acid Ends Up Where It Shouldn’t

Your esophagus meets your stomach at a muscular ring called the lower esophageal sphincter (LES). Under normal conditions, this sphincter opens briefly when you swallow, then squeezes shut to keep stomach contents from traveling upward. Two main types of sphincter malfunction drive reflux: abnormally frequent episodes where the sphincter relaxes on its own without a swallow, and chronically low resting pressure in the sphincter itself.¹ Those spontaneous relaxations account for almost all reflux episodes in healthy people and the majority in people with GERD.²

The interesting part is that people with GERD don’t necessarily have more of these spontaneous relaxations than people without it. The frequency is roughly similar. The difference is that when the sphincter does relax in GERD patients, the episode is more likely to involve acid reaching the esophagus.³ Think of it less as a broken gate that swings open too often and more as a gate that lets worse things through when it does open.

Once acid contacts the esophageal lining, the damage isn’t purely a chemical burn. The acid and bile in the refluxate trigger the esophageal cells themselves to release inflammatory signals, which recruit immune cells and break down the protective junctions between cells lining the esophagus.⁴ This means the tissue damage from chronic reflux is partly an inflammatory process driven by your own body’s response, not just acid eating through tissue.

Symptoms Beyond the Burn

The classic heartburn feeling is unmistakable for many people: a burning or hot sensation behind the breastbone, often worse after eating or when lying down, sometimes accompanied by a sour or bitter taste in the back of the throat. But reflux can announce itself in less obvious ways. When stomach contents reach the throat and voice box, a condition called laryngopharyngeal reflux, the symptoms shift to chronic cough, hoarseness, frequent throat clearing, and a persistent feeling of something stuck in the throat.⁵

Reflux is also increasingly recognized as a contributor to asthma flare-ups, chronic laryngitis, and even dental erosion from repeated acid exposure in the mouth.⁶ If you have a nagging cough that doesn’t respond to typical treatments or your dentist keeps flagging enamel wear on the backs of your teeth, reflux is worth investigating even if you never feel the classic burn.

When Heartburn Feels Like a Heart Attack

One of the most anxiety-inducing aspects of heartburn is how closely it can mimic cardiac chest pain. The lower esophagus and the heart share the same nerve supply, which means the location and spread of the pain can be identical.⁷ In a study of patients with known coronary artery disease who were experiencing chest pain, roughly a quarter of all recorded pain episodes turned out to be caused by acid reflux rather than cardiac problems.⁸ That finding matters because it means even people who have heart disease can’t reliably tell the difference on their own.

You might wonder whether the old emergency-room trick of giving someone a “GI cocktail” (a mix of antacid and a numbing agent) can sort out whether chest pain is cardiac or digestive. A systematic review found that relief from such a cocktail does not reliably rule out a heart problem.⁹ If you’re experiencing new or severe chest pain, especially with shortness of breath, jaw or arm pain, or lightheadedness, treat it as a potential cardiac event until proven otherwise.

What Makes Heartburn More Likely

Certain physical conditions and habits push the odds toward more frequent reflux. Excess body weight is one of the strongest and most studied risk factors. Higher BMI is associated with both hiatal hernia (where part of the stomach pushes through the diaphragm) and erosive esophagitis, with the probability of hiatal hernia rising at each level of BMI.¹⁰ Even mechanical pressure around the midsection matters. A study of volunteers showed that wearing a tight waist belt and having a larger waist circumference caused partial hiatal herniation and short-segment acid reflux, even in people with no history of reflux symptoms.¹¹

Pregnancy is another common trigger. About two thirds of pregnant people develop heartburn, driven mostly by hormonal changes (progesterone relaxes the lower esophageal sphincter), with the physical pressure of the growing uterus playing a smaller role.¹²

Certain medications can also promote reflux by reducing sphincter pressure, damaging the esophageal lining directly, or slowing the movement of food through the digestive tract.¹³ Common culprits include some blood pressure medications (particularly calcium channel blockers), certain asthma drugs, sedatives, and anti-inflammatory painkillers like ibuprofen. If you started a new medication around the time heartburn began, it’s worth discussing the connection with your prescriber.

The Stress Connection

People often report that heartburn flares during stressful periods, and the relationship is real but not as straightforward as “stress causes more acid.” In one study, researchers exposed participants to a stressor and measured both their actual reflux episodes and their reported symptoms. The stressor did not increase measured acid reflux, but the stressed participants perceived their symptoms as significantly worse.¹⁴ In other words, stress can amplify how much heartburn hurts without necessarily producing more acid.

The pathways behind this involve the brain-gut axis, a two-way communication system between the central nervous system and the digestive tract. Stress can increase the permeability of the esophageal lining, activate pain receptors, and alter how the brain processes signals from the gut, essentially turning the volume up on normal-level reflux.¹⁵ This explains why some people have terrible heartburn symptoms despite tests showing only mild acid exposure. Addressing stress doesn’t replace medical treatment, but it can meaningfully reduce how much discomfort reflux causes.

Functional Heartburn

There’s a surprisingly large group of people who experience chronic heartburn symptoms but show no evidence of abnormal acid reflux when tested. In gastroenterology, this is called functional heartburn, and it’s defined by the absence of objective reflux on monitoring and no response to acid-suppressing medication. These patients have a burning sensation that feels identical to GERD but isn’t being driven by acid.¹⁶ The esophageal nerve endings appear to be hypersensitive, firing pain signals in response to normal stimuli. Treatment approaches for functional heartburn tend to focus on nerve-calming medications and behavioral strategies rather than acid suppression, which is why getting the right diagnosis matters. Taking acid-blocking drugs for something that isn’t acid-driven exposes you to side effects with no corresponding benefit.

Fast-Acting Relief

For occasional heartburn, over-the-counter antacids (calcium carbonate, magnesium hydroxide) neutralize stomach acid within minutes. Their limitation is that relief fades quickly because new acid keeps being produced. Alginate-based formulations work differently. When they contact stomach acid, they form a floating gel “raft” on top of the stomach contents, creating a physical barrier that prevents acid from reaching the esophagus. This raft can stay in the stomach for several hours, providing longer-lasting relief than traditional antacids.¹⁷ Products combining alginate with antacid components offer both immediate neutralization and the sustained physical barrier, making them a solid choice for post-meal heartburn.

Acid-Suppressing Medications

When heartburn is frequent enough to need daily treatment, the two main classes of prescription or over-the-counter acid reducers are H2-receptor antagonists (like famotidine) and proton pump inhibitors (like omeprazole or lansoprazole). PPIs are the stronger option. They directly shut down the acid-producing pumps in the stomach lining and can keep stomach acidity suppressed for roughly 15 to 22 hours a day, compared to about four hours for H2 blockers.¹⁸

A Cochrane review confirmed that PPIs relieve heartburn better than H2 blockers both in people who haven’t had diagnostic testing and in those with confirmed GERD who have a normal-looking esophagus on endoscopy.¹⁹ That said, H2 blockers still have a role, particularly for people with milder symptoms, as a bedtime add-on for nocturnal reflux, or for those who don’t tolerate PPIs.

Risks of Long-Term Acid Suppression

PPIs are extremely effective, but using them for months or years comes with trade-offs that are worth knowing about. One well-established concern is rebound acid hypersecretion: when you stop taking a PPI after prolonged use, the stomach can temporarily overproduce acid, making symptoms worse than they were before you started.²⁰ This can create a cycle where people feel unable to stop the medication.

The strongest evidence of causality among long-term side effects points to increased susceptibility to certain gastrointestinal infections and that rebound acid effect.²¹ Observational studies have also linked prolonged PPI use to concerns including kidney problems, bone fractures, nutrient deficiencies (magnesium, vitamin B12, calcium), and an elevated risk of gut infections like C. difficile.²² The evidence for some of these associations is still debated, as much of it comes from observational data rather than controlled trials. But the general principle holds: PPIs should be used at the lowest effective dose for the shortest time needed, and periodically reconsidered rather than automatically refilled year after year.

A Newer Class of Acid Blockers

A newer group of drugs called potassium-competitive acid blockers (P-CABs) has entered the picture. The most prominent, vonoprazan, blocks the same acid pump that PPIs target but through a different binding mechanism that produces more rapid and sustained acid suppression.²³ Clinical evidence suggests that P-CABs have advantages in treating erosive esophagitis and perform at least as well as PPIs for ulcer healing.²⁴ Vonoprazan is already widely used in Japan and has been approved in the United States. Whether P-CABs will eventually replace PPIs as the go-to treatment or carve out a niche for harder-to-treat cases is still playing out.

Lifestyle Changes That Actually Help at Night

Nocturnal heartburn deserves special attention because lying flat eliminates gravity’s help in keeping acid in the stomach, and nighttime reflux disrupts sleep in ways that compound your misery the next day. Three lifestyle adjustments have evidence behind them for nighttime symptoms: elevating the head of the bed, extending the gap between dinner and bedtime, and sleeping on your left side.²⁵

Head-of-bed elevation means raising the entire upper body, not just propping up pillows under your head (which can actually increase abdominal pressure). A foam wedge or blocks under the bedposts work better. Sleeping on your left side reduces acid exposure in the esophagus compared to sleeping on the right side or flat on your back.²⁶ This works because of anatomy: when you lie on your left, the stomach hangs below the esophageal opening, and acid pools away from the valve. On your right, the stomach sits above the valve and acid essentially pours toward it.

The dinner-to-bed gap is commonly recommended, though the evidence is somewhat muddied by the fact that what you eat matters as much as when you eat it.²⁷ A large, fatty meal two hours before bed is going to cause more trouble than a light snack regardless of the time gap. Still, aiming for at least two to three hours between your last substantial meal and lying down is a reasonable practice.

When Heartburn Causes Lasting Damage

Most occasional heartburn is uncomfortable but harmless. Chronic, untreated reflux is a different story. Repeated acid exposure can damage the esophageal lining enough that the body replaces the normal tissue with a type more resistant to acid, a change known as Barrett’s esophagus. Barrett’s itself doesn’t cause symptoms, but it is a recognized precursor to esophageal adenocarcinoma, a cancer whose incidence has been rising in Western countries.²⁸ The absolute risk of any individual Barrett’s patient developing cancer is low in any given year, but the connection underscores why people with frequent, long-standing heartburn should get evaluated rather than just managing it indefinitely with over-the-counter remedies.

Surgical and Device-Based Options

For people who don’t respond to medication or who can’t tolerate long-term drug therapy, surgery is an option. The traditional procedure is Nissen fundoplication, where the top of the stomach is wrapped around the lower esophagus to reinforce the sphincter. It works well but carries trade-offs, most commonly difficulty belching, inability to vomit, and gas bloating.

A newer alternative is magnetic sphincter augmentation, a device marketed as the LINX system. It’s a small ring of magnetic beads placed around the outside of the lower esophageal sphincter. The magnets are strong enough to keep the sphincter closed against reflux but weak enough to allow food to pass when you swallow. Compared to Nissen fundoplication, the LINX device preserves the ability to belch and vomit at much higher rates, while achieving similar rates of eliminating PPI use.²⁹ The device also shows less bloating and better quality-of-life scores in comparison studies.³⁰ Neither procedure is taken lightly, and both require thorough testing beforehand to confirm that reflux is the actual problem, but they can be genuinely life-changing for people stuck in a cycle of daily medication and persistent symptoms.

The Esophageal Microbiome

One of the more surprising areas of recent research is the role of bacteria living in and around the esophagus. Historically, the esophagus was considered a relatively sterile passageway, but we now know it harbors its own microbial community. In people with GERD, the composition of that community shifts in ways that may actively contribute to inflammation and tissue damage. Disrupted microbial balance in the esophagus can activate immune and inflammatory pathways that worsen the cycle of reflux-related injury.³¹ This is still early-stage research, and no one is recommending specific probiotics for heartburn yet. But it adds another layer to the picture: heartburn isn’t just about acid volume and valve pressure. The microbial environment, the immune response, and even your psychological state all feed into how severe your symptoms become and how quickly tissue damage accumulates.