Constant heartburn happens when stomach acid repeatedly flows back into the esophagus, usually because the valve between your stomach and esophagus isn’t closing properly. This valve, a ring of muscle called the lower esophageal sphincter (LES), can weaken or relax at the wrong times due to a surprisingly wide range of causes, from the foods you eat to medications you take to the simple mechanics of body weight and gravity.
If heartburn is showing up more than twice a week and has persisted for several weeks, it’s generally classified as gastroesophageal reflux disease (GERD). Understanding what’s driving it is the first step toward making it stop.
How the Valve Between Your Stomach and Esophagus Fails
Your LES is supposed to open when you swallow and then snap shut to keep acid where it belongs. It’s a segment of smooth muscle controlled by nerves and hormones, which means a lot of different things can interfere with it. When it weakens or relaxes when it shouldn’t, acid rises into the esophagus and burns the lining, producing that familiar chest pain.
Age plays a role. The esophageal muscles and the LES itself tend to weaken over time, which is one reason heartburn becomes more common in middle age and beyond. But age alone rarely explains constant symptoms. More often, multiple factors pile on top of each other.
Excess Weight and Abdominal Pressure
Carrying extra weight around your midsection is one of the strongest drivers of persistent heartburn, and the mechanics are straightforward. Abdominal fat increases the pressure inside your abdomen, which pushes up against the stomach and forces its contents toward the esophagus. That elevated pressure also disrupts the junction where the esophagus meets the stomach, weakening the LES’s seal.
There’s a more specific problem too. In people with obesity, the upper part of the stomach stretches more after meals, which triggers spontaneous relaxations of the LES that aren’t preceded by swallowing. These are the body’s most common mechanism for reflux, and obese individuals experience significantly more of them, especially in the hours after eating. The increased abdominal pressure also promotes the formation of hiatal hernias, which compounds the problem further.
Hiatal Hernia
A hiatal hernia occurs when the upper part of your stomach bulges upward through the diaphragm into the chest cavity. The diaphragm normally acts as a second barrier reinforcing the LES. When part of the stomach slips above it, that reinforcement disappears, and acid can flow into the esophagus much more easily. Small hiatal hernias often cause no symptoms at all, but larger ones allow enough acid backflow to produce constant heartburn.
Foods and Substances That Relax the Valve
Certain foods don’t just irritate the esophagus on the way down. They actually relax the LES, giving acid a clear path upward. The most consistent culprits are high-fat, high-salt, and heavily spiced foods: fried food, fast food, pizza, fatty meats like bacon and sausage, and cheese. These slow digestion and let food sit in the stomach longer, increasing the window for reflux.
Other foods cause the same problem through different pathways:
- Chocolate and peppermint directly relax the LES muscle
- Tomato-based sauces and citrus fruits increase stomach acidity and irritate the esophageal lining
- Carbonated beverages distend the stomach with gas, triggering valve relaxation
- Alcohol loosens the LES
- Nicotine relaxes the LES, making smoking and tobacco use significant contributors
If your diet regularly includes several of these, you may be triggering reflux multiple times a day without realizing any single food is the problem.
Medications That Make Heartburn Worse
A number of common medications can cause or worsen persistent heartburn through two different mechanisms. Some directly irritate the esophageal lining as they pass through, while others relax the LES and increase acid reflux itself.
Medications that irritate the esophagus include common pain relievers like ibuprofen and aspirin, certain antibiotics, iron supplements, potassium supplements, and bisphosphonates (often prescribed for osteoporosis). If you’ve started one of these and noticed heartburn getting worse, the timing may not be coincidental.
A separate group of medications actually promotes reflux by loosening the LES or slowing stomach emptying. This includes calcium channel blockers and nitrates used for blood pressure or heart disease, tricyclic antidepressants, opioid pain medications, sedatives, and progesterone-containing hormone preparations. If you take any of these daily, they could be a significant contributor to heartburn that never seems to go away.
Hormones and Pregnancy
Progesterone relaxes smooth muscle throughout the body, including the LES. This is why heartburn is extremely common during pregnancy, when progesterone levels rise steadily. The growing uterus also increases abdominal pressure, creating a double mechanism for reflux. Heartburn during pregnancy tends to worsen in the third trimester as both hormone levels and physical pressure peak.
Hormone replacement therapy containing progesterone can produce the same effect outside of pregnancy. Oral contraceptives with progesterone are also known to contribute.
Why Heartburn Gets Worse at Night
If your heartburn is worst when you’re lying down or wakes you from sleep, gravity is a major factor. When you’re upright, gravity helps keep stomach contents in place. Lying flat removes that advantage, and acid pools against the LES for hours.
Your sleep position matters more than you might expect. Sleeping on your right side is associated with more reflux episodes because of how the stomach sits relative to the esophagus in that position. The American Gastroenterological Association recommends sleeping on your left side, which leverages gravity and anatomy to reduce acid exposure. Elevating your head and upper body by about six inches (using a wedge pillow, not just stacking pillows) also helps keep acid down.
Eating within two to three hours of bedtime makes nighttime reflux significantly worse because your stomach is still actively producing acid to digest the meal.
When Constant Heartburn Causes Damage
Heartburn that persists for months or years isn’t just uncomfortable. Repeated acid exposure can inflame and damage the esophageal lining, a condition called esophagitis. Over time, the cells lining the lower esophagus can change in response to chronic acid injury, a condition called Barrett’s esophagus. Barrett’s itself usually doesn’t cause symptoms beyond the heartburn you’re already feeling, but it carries a small ongoing risk of progressing to esophageal cancer, estimated at about 0.3% per year in people without precancerous cell changes.
This risk is low for any individual year but accumulates over decades, which is why persistent heartburn that doesn’t respond to lifestyle changes warrants evaluation rather than indefinite self-treatment with antacids.
How Constant Heartburn Is Managed
Treatment starts with lifestyle modifications because they address root causes rather than masking symptoms. Losing weight (if you carry excess abdominal weight), avoiding trigger foods, not eating close to bedtime, quitting smoking, and adjusting sleep position can each reduce reflux meaningfully. Stacking several of these changes together often produces more relief than any single intervention.
When lifestyle changes aren’t enough, proton pump inhibitors (PPIs), the most common acid-reducing medications, are the standard medical treatment for confirmed GERD with predominant heartburn. Current guidelines recommend using the lowest effective dose for the shortest duration necessary, then transitioning to a long-term plan that may include continued lifestyle management, intermittent medication use, or in some cases, a surgical procedure to reinforce the LES.
If you’ve been taking over-the-counter antacids or acid reducers daily for weeks without improvement, that’s a signal to get evaluated. The goal isn’t just symptom control. It’s identifying which of the causes above are driving your specific pattern and addressing them directly.