Risk Factors

Your lower esophageal sphincter (LES) often does a fine job of keeping stomach contents from moving back up into your esophagus, but not always. In fact, this muscle can be weakened by several different kinds of events. When that happens, it increases the risk of acid reflux and heartburn. Your LES may be weakened and your risk of heartburn may be higher if any of the following situations apply to you:

You gain too much weight: Carrying around extra pounds increases pressure in your abdomen, which strains the LES. Overweight people (BMI of 25 to 29.9) suffer from frequent heartburn one and a half times more often than thinner people (BMI under 25). Obese people (BMI of 30 or higher) experience frequent heartburn at twice the rate of thinner people. A BMI between 18.5 and 24.9 is considered ideal. What's your BMI? Check it here.

You have a hiatal hernia: This condition occurs when the top of the stomach and the LES push through the diaphragm (the muscular barrier at the top of the abdomen) and reach part way into the chest cavity. Most of the time, the condition does not produce any symptoms. But in some people, a hiatal hernia encourages acid reflux and frequent heartburn. The risk of a hiatal hernia increases with age. Here is what a hiatal hernia might feel like.

You take certain medications: Medications used to treat depression, high blood pressure, heart conditions, anxiety, and asthma -- just to name a few -- can relax the LES, allowing stomach contents to move back up into the esophagus. Taking antihistamines, birth control pills, nonsteroidal anti-inflammatory drugs (NSAIDs), or antispasmodics can increase the risk of heartburn, too.

You are pregnant: Hormones and weight gain during pregnancy affect the LES and increase the risk of heartburn. Heartburn in pregnancy is quite common. It occurs in about 30%–50% of all pregnancies.

You experience a great deal of stress: Chronic stress has been linked to severe heartburn. Stress can boost the production of stomach acid and slow digestion, both of which make it easier for acid to reflux and come into contact with the esophagus. Stress also lowers the threshold for experiencing heartburn pain -- you're more likely to feel the acid reflux if you're stressed.

You smoke: Although smoking does not cause acid reflux, studies show that it can exacerbate it.