Hiatal hernias are extremely common. Estimates vary depending on how they’re measured, but studies consistently find them in a significant portion of adults, with rates climbing sharply after age 50. Many people have one and never know it, since a large number of hiatal hernias produce no symptoms at all and are only discovered when imaging or an endoscopy is done for another reason.
Overall Prevalence
Pinning down an exact number is tricky because so many hiatal hernias go undetected. Population-based studies using upper endoscopy or barium swallow exams have found hiatal hernias in roughly 20% to 60% of adults, with the wide range reflecting differences in how the hernia is defined, the population studied, and the imaging method used. The most commonly cited figure is that about 1 in 5 adults has a hiatal hernia at any given time, but the true number is likely higher since many are never tested.
Age is the single biggest factor driving those numbers. Hiatal hernias become progressively more common with each decade of life, and by age 60, they’re found in the majority of people who undergo upper endoscopy. The tissues around the opening in your diaphragm (the hiatus) naturally weaken and stretch over time, making it easier for the upper part of the stomach to push through.
Why So Many Go Unnoticed
A hiatal hernia happens when part of your stomach slides up through the opening in your diaphragm where your esophagus passes through. In most cases, the hernia is small and causes no discomfort whatsoever. These silent hernias are often discovered incidentally during imaging ordered for something else entirely, like a CT scan for chest pain or an endoscopy to investigate swallowing problems. Because there’s no routine screening for hiatal hernias, the number of undiagnosed cases is substantial.
When symptoms do appear, they usually overlap with acid reflux: heartburn, regurgitation, chest discomfort after eating, or difficulty swallowing. This overlap means some people are treated for reflux without ever being told they have a hiatal hernia behind it.
Sliding vs. Paraesophageal Types
Not all hiatal hernias are the same, and the type you have matters more than the fact that you have one. The vast majority, roughly 95% to 99%, are Type I or “sliding” hernias. In a sliding hernia, the junction where the esophagus meets the stomach moves upward through the diaphragm. These tend to be small, often cause no symptoms, and rarely require treatment beyond managing reflux if it’s bothersome.
The remaining 1% to 5% are paraesophageal hernias (Types II through IV), where part of the stomach pushes up alongside the esophagus rather than sliding straight through. These are less common but more concerning because the herniated portion of the stomach can become trapped or lose its blood supply. Type IV, sometimes called a giant hiatal hernia, is the rarest, occurring in roughly 0.1% of all cases. Paraesophageal hernias are more likely to need surgical repair even when symptoms are mild.
Who Gets Them
Age is the dominant risk factor. The diaphragm weakens naturally over decades, and the connective tissue holding the stomach in place becomes more lax. Pregnancy, repeated heavy lifting, chronic coughing, and prior abdominal surgery can all increase the pressure inside the abdomen and contribute to hernia formation. Some people are simply born with a larger-than-average hiatus, which predisposes them from the start.
Interestingly, the relationship between body weight and hiatal hernias is less clear-cut than most people assume. A study published in the American Journal of Gastroenterology found that hernia rates were similar across BMI categories, with 29% prevalence in normal-weight individuals and 19% in those with a BMI above 35. The researchers concluded that obesity was not associated with a higher prevalence of hiatal hernia, and that hernias were actually less common in the morbidly obese group. That said, excess weight does worsen reflux symptoms in people who already have a hernia, even if it doesn’t cause the hernia itself.
How They’re Detected
Hiatal hernias are typically found through one of three methods: upper endoscopy, barium swallow, or CT scan. None of these is perfect. Endoscopy detects hiatal hernias about 75% of the time, while barium swallow catches them at a similar rate of roughly 77%. This means that even when a test is done, a small hernia can be missed, especially if the stomach slides in and out of position during the exam. CT scans may pick up hernias incidentally during chest or abdominal imaging, and newer measurement techniques using CT are being studied as more objective detection tools.
Because detection depends on timing and technique, your hernia might show up on one test and not another. A sliding hernia can literally slide back to its normal position while you’re lying on the exam table, then reappear when you stand up or strain.
When Treatment Becomes Necessary
Most hiatal hernias never need treatment. If yours causes no symptoms, there’s nothing to fix. For those with reflux symptoms, the approach typically starts with lifestyle changes (eating smaller meals, not lying down right after eating, elevating the head of the bed) and medications that reduce stomach acid.
Surgery is reserved for hernias that cause persistent symptoms despite medication, or for paraesophageal hernias that carry a risk of complications. Over the decade from 2010 through 2019, roughly 518,000 hospitalizations in the United States included a hiatal hernia repair, averaging about 50,000 per year. That’s a small fraction of the millions of Americans living with the condition, which underscores how rarely surgery is actually needed. When it is performed, the procedure is most often done laparoscopically, involving small incisions and a recovery period of a few weeks.
The bottom line is that hiatal hernias are one of the most common anatomical findings in the adult population, especially after middle age. Having one is far more common than not having one in older adults, and the overwhelming majority never cause serious problems.