Frequent heartburn happens when stomach acid repeatedly flows back into your esophagus, the tube connecting your mouth to your stomach. A ring of muscle at the bottom of your esophagus normally acts as a one-way valve, opening to let food down and closing to keep acid where it belongs. When that valve relaxes at the wrong time, weakens over time, or gets overwhelmed by pressure from below, acid escapes upward and burns the sensitive lining of your esophagus. If this is happening to you more than occasionally, something specific is driving it.
How the Valve Fails
That muscular valve, called the lower esophageal sphincter, is the key player. In a healthy system, it stays closed except when you swallow. But certain foods, habits, medications, and structural changes can cause it to relax when it shouldn’t or stay slightly open. Every time it does, acidic stomach contents wash upward. The esophagus has no protective mucus layer like your stomach does, so even brief contact with acid causes that familiar burning sensation behind your breastbone.
When heartburn happens once in a while after a big meal, it’s usually a temporary issue. When it keeps coming back, something in your daily life is repeatedly triggering that valve to malfunction, or a structural problem is making it harder for the valve to do its job.
Foods and Drinks That Relax the Valve
Diet is the most common and most fixable cause of frequent heartburn. Certain foods and drinks directly loosen the sphincter or ramp up acid production in your stomach, sometimes both at once.
Coffee, tea, cocoa, cola, and other caffeinated drinks both relax the valve and stimulate your stomach to produce more acid. Chocolate and mint have the same valve-loosening effect, which is worth knowing since both are popular after-dinner choices. Fried and fatty foods slow digestion and keep your stomach fuller for longer, increasing the pressure pushing acid upward. Alcohol, citrus, tomato-based foods, and spicy dishes are also well-known triggers, though sensitivity varies from person to person.
The pattern matters as much as the specific foods. Large meals stretch the stomach and put more pressure on the valve. Eating within two to three hours of lying down gives gravity less time to help keep acid in your stomach. If your heartburn tends to hit at night, a late dinner or bedtime snack is a likely culprit.
Body Weight and Abdominal Pressure
Carrying extra weight, especially around your midsection, physically compresses your stomach and pushes its contents upward against the valve. This is one of the strongest and most well-documented drivers of chronic heartburn. The relationship is dose-dependent: the more excess weight, the more frequent and severe the symptoms tend to be.
The good news is that losing weight reliably improves symptoms. A large population study found that a moderate reduction in body mass over time decreased the risk of frequent heartburn by nearly 40%. Hospital-based research has shown that losing 5 to 10% of body weight in women, and more than 10% in men, led to significant drops in overall symptom scores. For someone weighing 200 pounds, that means losing 10 to 20 pounds could make a noticeable difference. Tight clothing around the waist creates a milder version of the same problem by squeezing the abdomen.
Medications That Make It Worse
Several common medications can trigger or worsen heartburn, and this is an often-overlooked cause. Some directly irritate the esophageal lining on the way down: ibuprofen, aspirin, certain antibiotics, iron supplements, and bone-density medications can all cause a burning pain that mimics or compounds reflux.
A separate group of medications actually weakens the sphincter itself, making true acid reflux more likely. Blood pressure medications like calcium channel blockers and nitrates fall into this category, along with certain antidepressants, sedatives, opioid painkillers, and progesterone. If your heartburn started or worsened around the time you began a new medication, that connection is worth exploring with whoever prescribed it.
Structural Problems: Hiatal Hernia
Sometimes frequent heartburn has a physical, structural cause. A hiatal hernia occurs when the upper part of your stomach pushes up through the opening in your diaphragm where the esophagus passes through. Normally, the diaphragm reinforces the sphincter valve from the outside, adding an extra layer of defense against reflux. When a hernia displaces that junction, both defense mechanisms are compromised.
The connection between hiatal hernias and chronic heartburn is strong. Studies from the US and Western Europe have found that 50 to 94% of patients with reflux-related esophageal inflammation also had a hiatal hernia, compared to 13 to 59% in control groups without reflux problems. Many small hiatal hernias cause no symptoms at all, but larger ones can make reflux persistent and harder to control with lifestyle changes alone.
Why It Gets Worse at Night
If your heartburn flares when you lie down, gravity is the main reason. When you’re upright, gravity helps keep stomach acid where it belongs. The moment you recline, acid can flow freely toward the esophagus and pool there, prolonging contact and irritation. Swallowing, which normally pushes refluxed acid back down, slows dramatically during sleep. Saliva production also drops at night, removing another natural acid-neutralizing mechanism.
Two practical changes help with nighttime symptoms. Elevating the head of your bed by about 30 degrees (roughly 6 to 8 inches) uses gravity to your advantage without requiring you to sleep sitting up. Sleeping on your left side also helps, because of the way the stomach curves: in this position, the junction where acid enters the esophagus sits above the pool of stomach contents rather than below it. Combining both strategies is more effective than either one alone.
Other Habits That Contribute
Smoking weakens the esophageal sphincter and reduces saliva production, hitting you with a double problem. Stress doesn’t directly cause acid production to spike, but it does increase your sensitivity to pain in the esophagus, making the same amount of reflux feel worse. Carbonated drinks introduce gas that distends the stomach and forces the valve open. Even vigorous exercise, particularly anything involving bending, crunching, or high-impact bouncing, can push stomach contents upward during a workout.
When Heartburn Becomes GERD
Gastroesophageal reflux disease, or GERD, is the clinical term for when reflux becomes chronic and starts causing complications or significantly affecting quality of life. If you’re reaching for antacids multiple times a week or rearranging your life around your symptoms, you’re likely in GERD territory. An initial course of acid-reducing medication taken once daily before meals for about eight weeks is a standard first step when lifestyle changes alone aren’t enough.
Most people with GERD manage well with a combination of dietary changes, weight management, and medication when needed. But persistent, uncontrolled reflux does carry long-term risks. Years of acid exposure can change the cells lining the lower esophagus, a condition called Barrett’s esophagus. Among people with Barrett’s who don’t have precancerous changes, the annual risk of developing esophageal cancer is low, roughly 0.1 to 0.4% per year. That risk climbs with precancerous changes, but the overall progression rate remains modest. The point isn’t to panic but to take chronic symptoms seriously enough to address them rather than just endure them.
Red Flags Worth Knowing
Certain symptoms alongside heartburn signal something more urgent. Difficulty swallowing, unintentional weight loss, vomiting, signs of bleeding (like dark or bloody stools), unexplained anemia, or chest pain that doesn’t clearly feel like heartburn all warrant prompt medical evaluation. These are considered alarm symptoms, and they typically lead to an endoscopy to look directly at the esophagus and rule out complications.