The familiar rumbling or growling sound coming from your abdomen is a normal function of your gastrointestinal (GI) tract. While often associated with hunger, the medical term for this phenomenon, borborygmi, describes any noise made by the digestive system as it works. These sounds are produced primarily by the small and large intestines, not the stomach alone.
The Physical Mechanism of the Noise
The sound of gurgling is created by the movement of gas and liquid through the digestive tract. This transport relies on peristalsis, a process where the smooth muscles lining the GI tract contract in rhythmic, wave-like motions. These contractions propel the contents—a mixture of partially digested food, digestive juices, and air—along the intestinal path.
The air consists of gas produced by intestinal bacteria and air swallowed while talking, eating, or drinking. When these pockets of gas and liquid are squeezed through the narrow sections of the intestines, it creates an audible sound. Since the abdomen allows sound to travel, these sloshing and gurgling noises can easily be heard from the outside.
The Hunger Signal and the Migrating Motor Complex
The sounds become noticeably louder when you are hungry due to a specific cleaning cycle in the digestive system. Approximately two hours after the stomach and small intestine have emptied, the body initiates the Migrating Motor Complex (MMC). The MMC is often called the “housekeeper” of the gut because its purpose is to sweep remaining debris, indigestible matter, and stray bacteria out of the small intestine.
The MMC cycles through four phases, including a short burst of high-amplitude contractions that move through the gut every 90 to 120 minutes. This intense muscular activity is regulated by hormones like ghrelin, the “hunger hormone,” which signals the brain that the body is in a fasted state. When the MMC is active, the sounds are amplified because there is no solid food present to dampen the noise. The empty chambers of the stomach and intestines allow the moving gas and fluid to echo loudly.
When to Pay Attention to Gurgling
While borborygmi is a normal sign of a working digestive system, excessive or painful gurgling may signal an underlying issue. Normal sounds are usually intermittent and quiet, but a noticeable increase in frequency or volume warrants attention, especially if accompanied by other symptoms. Conditions that affect the GI tract’s ability to properly move contents can lead to hyperactive bowel sounds.
You should seek medical advice if loud gurgling is persistent and occurs alongside severe abdominal pain or a change in bowel habits. Concerning symptoms might include chronic diarrhea or constipation, bloating, vomiting, or unexplained weight loss. Such combinations could indicate issues like Irritable Bowel Syndrome (IBS), a food intolerance, or a more serious condition requiring professional diagnosis.