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What Causes Stomach Rumbling

What Causes Stomach Rumbling

We all know we should eat when our stomach growls, but why exactly does it have to make all that racket?

It’s common knowledge that stomach rumbling is a sign of hunger, but have you ever wondered what’s behind all that noise? The answer is actually quite simple; it’s the contractions our stomach makes when it’s getting ready for food.

Here’s how it happens. When you haven’t eaten for two hours receptors in the walls of your stomach trigger the release of a hormone called ghrelin. This hormone lets the brain know you’re stomach is empty. Other functions send the exact same message, like low blood sugar, all in effort to trigger a hunger response so you replenish vital nutrients.

why stomach growls 550x366 What Causes Stomach Rumbling

What Causes Stomach Rumbling

Image Credit: Perfecto Insecto, 2008.

Next the brain steps in to resolve this feeling by releasing another hormone called orexin; this tells your stomach it’s now time to eat. It’s the Hypothalamus, a thumbnail sized portion of the brain, that’s responsible for this process. It also controls other metabolic processes and autonomic nerves systems such as thirst, body temperature, sleep and fatigue, and sex drive.

Once the hormones hit the stomach its muscles begin to contract. Digestive fluids are then released into the stomach and intestines, clearing the space in anticipation of food.

These contractions move in a ring-shaped formation throughout the gut to push any remaining food, mucus or bacteria out of the way. All this movement produces vibrations; vibrations which are further amplified by the empty space in the stomach. This is the growling you can hear.

The rumbles can last for up to 20 mins, and will repeat every 2 hours or so until you’ve had your next meal.

Many people will have also notice slight rumbling coming from a full stomach, and that’s because the same muscles are also responsible for digesting food with gas and fluid, and then easing the mixture down into the intestinal tract. This produces a similar stomach murmur, however it’s considerably quieter when the stomach is full and there’s no room for the sound to reverberate around.

Thanks to Gizmodo contributor Rachel Sawby, who provided the easily comprehensible article that made this post possible.


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  1. Rachel Swaby: Why Your Stomach Growls. Gizmodo, 10/11/2011.

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