Heartburn happens when stomach acid flows backward into the esophagus, the tube connecting your mouth to your stomach. A muscular valve at the bottom of the esophagus, called the lower esophageal sphincter, normally keeps acid where it belongs. When that valve weakens or relaxes at the wrong time, acid escapes upward and causes the familiar burning sensation behind your breastbone. The triggers range from what you ate for dinner to underlying medical conditions.
Foods That Trigger Heartburn
Certain foods relax the esophageal sphincter and slow digestion, letting food sit in your stomach longer and giving acid more opportunity to creep upward. The most common culprits are foods high in fat, salt, or spice: fried food, fast food, pizza, processed snacks like potato chips, fatty meats such as bacon and sausage, and cheese. These aren’t just anecdotal triggers. High-fat meals delay stomach emptying, which increases the window for reflux.
Several other foods cause problems through different mechanisms. Tomato-based sauces and citrus fruits are highly acidic on their own, so they irritate an already-sensitive esophagus. Chocolate and peppermint both relax the sphincter directly. Carbonated beverages increase pressure inside the stomach by introducing gas, which can force the valve open. Spices like cayenne, black pepper, and white pepper don’t necessarily relax the sphincter but can inflame the esophageal lining when acid does reach it.
Eating Habits and Timing
It’s not just what you eat. Eating large meals stretches the stomach and puts pressure on the sphincter. Eating within two hours of lying down is one of the most reliable ways to trigger nighttime heartburn, because gravity is no longer helping keep acid in the stomach. When you’re upright, acid has to travel upward to reach the esophagus. When you’re flat on your back, it flows freely.
Research on reflux patterns confirms that most measurable reflux in many patients occurs exclusively in the supine (lying down) position. Elevating the head of the bed by about 6 inches significantly reduces or completely resolves nighttime reflux in the majority of people studied. That means using a wedge or raising the bed frame, not just stacking pillows, which tend to bend you at the waist without actually changing the angle of your esophagus relative to your stomach.
Smoking and Alcohol
Smoking directly weakens the esophageal sphincter, making it easier for acid to escape. It also reduces saliva production, which matters because saliva is mildly alkaline and helps neutralize small amounts of acid that reach the esophagus. The combination of a weaker valve and less natural acid protection makes smokers significantly more prone to heartburn.
Alcohol has a similar double effect. It relaxes the sphincter and irritates the esophageal lining. Wine, beer, and spirits can all trigger symptoms, though the effect varies from person to person.
Excess Weight and Abdominal Pressure
Carrying extra weight around your midsection increases pressure inside the abdomen, which pushes against the stomach and displaces the esophageal sphincter. This increased pressure gradient makes it physically easier for acid to be forced upward. The relationship between body weight and heartburn frequency is well documented: as BMI rises, so does reflux risk. Even moderate weight gain can worsen symptoms in someone who was previously fine, and weight loss is one of the most effective non-medication strategies for reducing chronic heartburn.
Tight clothing around the waist, heavy lifting, and frequent bending over create the same kind of abdominal pressure on a shorter timescale.
Medications That Cause Heartburn
More than 100 different medications have been reported to irritate the esophagus or worsen reflux. Some damage the esophageal lining directly (a condition called pill esophagitis), while others relax the sphincter as a side effect.
Common offenders include:
- Pain relievers like ibuprofen, aspirin, and naproxen, which irritate the stomach lining and increase acid production
- Antibiotics, which account for roughly half of all reported cases of pill-related esophageal irritation, with tetracyclines being the most frequent cause
- Blood pressure medications in the calcium channel blocker class, which relax smooth muscle throughout the body, including the esophageal sphincter
- Bone-density medications used for osteoporosis, which can cause severe esophageal irritation if they don’t reach the stomach quickly
If heartburn started or worsened after beginning a new medication, the timing is worth noting. Taking pills with a full glass of water and staying upright for at least 30 minutes afterward reduces the risk of pill esophagitis.
Pregnancy
Heartburn typically appears in the second or third trimester of pregnancy, and the cause is largely hormonal. Rising progesterone levels relax the esophageal sphincter, making it less effective as a barrier. Progesterone also slows the digestive process overall, keeping food in the stomach longer and giving acid more time to reflux.
As the pregnancy progresses, the growing uterus adds a physical component by pushing upward against the stomach. This combination of hormonal relaxation and mechanical pressure explains why heartburn tends to get worse as the due date approaches and resolves after delivery.
Hiatal Hernia
A hiatal hernia occurs when the upper part of the stomach pushes through the diaphragm, the muscle separating your chest from your abdomen. The esophageal sphincter normally sits right at the level of the diaphragm, which provides extra reinforcement. When the stomach slides above the diaphragm, that reinforcement is lost, and the sphincter can’t do its job as effectively.
Many people with small hiatal hernias have no symptoms at all. But among those who do develop symptoms, the most common ones are related to chronic acid reflux: heartburn, regurgitation, and difficulty swallowing. Larger hernias tend to cause more problems. A hiatal hernia doesn’t guarantee heartburn, but it makes the mechanical conditions for reflux much more favorable.
Stress and Sleep Deprivation
Stress doesn’t directly increase acid production the way people often assume, but it lowers your threshold for perceiving discomfort. The esophagus becomes more sensitive to normal amounts of acid exposure during periods of high stress or poor sleep. Practically speaking, the same amount of reflux that you wouldn’t notice on a good day can feel painful when you’re stressed or exhausted. Stress also tends to drive behaviors that worsen reflux: eating quickly, choosing convenience foods, drinking more alcohol or coffee, and going to bed late after eating.
When Heartburn Mimics Something Serious
Heartburn and heart attacks can feel remarkably similar. Even experienced doctors sometimes can’t distinguish them based on symptoms alone. Typical heartburn produces a burning sensation in the chest that usually occurs after eating or while lying down, is relieved by antacids, and may come with a sour taste or small amounts of fluid rising into the throat.
A heart attack more commonly involves pressure, tightness, or squeezing in the chest or arms that may spread to the neck, jaw, or back. It’s often accompanied by shortness of breath, cold sweat, lightheadedness, or sudden fatigue. Women are more likely than men to experience jaw pain, back pain, nausea, or shortness of breath rather than classic chest pain.
The key distinction: persistent chest pain you can’t explain, especially with any of the additional symptoms listed above, warrants emergency medical attention. The pain doesn’t have to last a long time to be a warning sign.
When Occasional Becomes Chronic
Occasional heartburn after a large or spicy meal is extremely common and typically responds to over-the-counter antacids. When heartburn happens twice a week or more, or when it persists despite avoiding known triggers, it may be classified as gastroesophageal reflux disease (GERD). Current clinical guidelines recommend an initial 8-week trial of acid-suppressing medication for classic GERD symptoms. If symptoms don’t respond to that trial, or if they return after stopping medication, an endoscopy (a scope examination of the esophagus) is the next step to check for damage or other conditions.
Chronic, untreated reflux can inflame and damage the esophageal lining over time. Persistent heartburn that doesn’t improve with dietary changes and basic medication is worth investigating, not because it’s always serious, but because effective treatment exists and long-term esophageal irritation is preventable.