Constant acid reflux happens when the muscular valve between your esophagus and stomach stops doing its job reliably. This valve, called the lower esophageal sphincter, is supposed to open when you swallow and close the rest of the time. When it relaxes too often, stays too weak, or gets structurally displaced, stomach acid washes back up into your esophagus repeatedly, sometimes dozens of times a day. If you’re experiencing reflux more than twice a week for several weeks, you likely have gastroesophageal reflux disease, or GERD.
How the Valve Between Your Stomach and Esophagus Fails
Your body has a two-part system for keeping acid where it belongs. The first part is the sphincter muscle itself, which sits at the bottom of your esophagus and maintains a resting squeeze pressure. The second part is your diaphragm, the large breathing muscle that wraps around the same area and reinforces the seal. These two components work together, and when either one weakens, reflux follows.
Sphincter dysfunction takes two main forms. The more common one is an abnormally high rate of spontaneous relaxations, moments when the valve opens for no good reason, letting acid splash upward. The second is chronically low resting pressure in the valve, meaning it never fully closes in the first place. Both patterns appear to stem primarily from faulty nerve signaling to the muscle rather than a problem with the muscle tissue itself. That’s why reflux can be so persistent: it’s not just a structural problem you can stretch or strengthen away.
Hiatal Hernia and Its Role
A hiatal hernia occurs when the upper portion of your stomach slides upward through the opening in your diaphragm, pulling the sphincter into your chest cavity. This separates the two parts of the anti-reflux barrier that normally overlap and reinforce each other. Once the sphincter is no longer sitting inside your abdomen, it loses the benefit of abdominal pressure helping to keep it shut. A small flap of tissue at the junction between your stomach and esophagus, which acts like a one-way valve, also gets disrupted.
Hiatal hernias are extremely common and don’t always cause symptoms. But when they do contribute to reflux, they tend to make it chronic because the structural displacement doesn’t reverse on its own. People with a hiatal hernia also clear acid from their esophagus more slowly, which means each reflux episode causes longer exposure to acid and more tissue irritation.
What You Eat and When You Eat It
Fat slows the rate at which your stomach empties. The longer food and acid sit in your stomach, the more opportunities there are for reflux. High-fat meals, fried foods, and greasy dishes are the most consistent dietary triggers for this reason. It’s not just that fat feels heavy; it physically keeps your stomach full longer, increasing the pressure against a valve that may already be compromised.
Large meals create the same problem through sheer volume. Eating a big dinner and lying down within two or three hours is one of the most reliable ways to trigger reflux, because gravity is no longer helping keep acid in your stomach while your stomach is still actively digesting. Alcohol, coffee, chocolate, mint, and acidic foods like tomatoes and citrus can also relax the sphincter or directly irritate an already-inflamed esophagus, though individual sensitivity varies widely. Paying attention to which foods consistently precede your symptoms matters more than following a generic avoid list.
Medications That Make Reflux Worse
Several common prescription medications weaken the esophageal sphincter as a side effect. Calcium channel blockers (used for blood pressure), nitrates (used for chest pain), and theophylline (used for asthma) all reduce the sphincter’s resting pressure. If your reflux started or worsened around the time you began a new medication, that connection is worth exploring with your prescriber. Anti-inflammatory painkillers like ibuprofen and aspirin can also irritate the esophageal lining directly, compounding the problem even if they don’t affect the valve itself.
Body Weight and Abdominal Pressure
Excess weight around your midsection increases pressure inside your abdomen, which pushes against your stomach and forces acid upward. This is one of the most well-established risk factors for chronic reflux, and it operates through pure mechanics. Even modest weight gain can tip someone from occasional heartburn to daily symptoms, particularly if they already have a mildly weak sphincter. The reverse is also true: losing weight is one of the few lifestyle changes that consistently reduces reflux frequency in studies, not just symptom severity.
Hormonal Changes During Pregnancy
Pregnancy causes reflux through a double mechanism. Rising progesterone levels relax the esophageal sphincter, making it easier for acid to escape. At the same time, the growing uterus increases abdominal pressure, pushing the stomach upward. This combination explains why heartburn is rare in the first trimester and increasingly common toward the end of pregnancy. For most women, reflux resolves after delivery once hormone levels normalize and abdominal pressure drops.
Why Reflux Gets Worse at Night
Lying flat removes gravity from the equation, so acid that enters your esophagus doesn’t drain back down as quickly. You also swallow less frequently during sleep, and swallowing is one of the main ways your esophagus clears acid. The result is longer acid exposure per episode, even if you don’t have more episodes overall.
Sleep position makes a measurable difference. Research from Harvard Health found that sleeping on your left side doesn’t reduce the number of reflux episodes, but acid clears from the esophagus significantly faster compared to sleeping on your back or right side. Elevating the head of your bed by six to eight inches (using a wedge or bed risers, not just extra pillows) also helps by creating a gentle downhill slope from esophagus to stomach.
Stress, Smoking, and Other Contributors
Smoking weakens the esophageal sphincter, increases stomach acid production, and reduces saliva output. Saliva is mildly alkaline and helps neutralize acid in your esophagus, so less of it means slower recovery from each reflux episode. Chronic stress doesn’t directly cause more acid production, but it lowers the threshold at which you perceive pain in the esophagus, making the same amount of reflux feel worse. People under sustained stress also tend to eat more, eat faster, drink more alcohol, and sleep less, all of which independently worsen reflux.
What Happens If Reflux Continues Unchecked
Chronic acid exposure inflames the esophageal lining, a condition called esophagitis, which can cause pain, difficulty swallowing, and eventually scarring that narrows the esophagus. Between 10% and 15% of people with long-standing GERD develop Barrett’s esophagus, a condition where the cells lining the lower esophagus change to resemble intestinal tissue. Barrett’s esophagus is considered a precancerous condition, though the actual risk of it progressing to esophageal cancer is about half a percent per year. That’s low enough that most people with Barrett’s are monitored rather than treated aggressively, but it’s a strong reason not to ignore years of daily reflux.
Certain symptoms signal that reflux may have already caused complications. Trouble swallowing food, unintentional weight loss, vomiting blood or material that looks like coffee grounds, and black or bloody stools all warrant prompt medical evaluation. Chest pain that occurs with physical activity, like climbing stairs, should also be assessed quickly because it can mimic or coexist with heart problems.
Why Over-the-Counter Antacids Aren’t Enough
Antacids neutralize acid that’s already in your esophagus, which provides quick relief but does nothing about the underlying valve dysfunction. If you’re reaching for antacids daily, you’re treating symptoms while the cause continues unchecked. Proton pump inhibitors reduce acid production at the source and are effective for healing esophageal inflammation, but they work best as part of a broader approach that includes identifying your specific triggers. Some people need them long-term; others can step down to occasional use once they’ve addressed weight, diet, meal timing, sleep position, and any contributing medications.
The reason you have acid reflux “all the time” is almost never a single cause. It’s usually a combination: a valve that doesn’t close well, eating patterns that increase stomach pressure, a body position that removes gravity’s help, and possibly a medication or anatomical factor adding to the mix. Identifying which combination applies to you is the most productive path forward.