Why does your tummy rumble when you’re hungry?
Let’s take a trip through your gut to find out…
So, you’re writing exams and the hall’s really quiet, then all of a sudden, your stomach starts to gurgle so loudly that everyone around you can hear it. Embarrassing!
But what makes your gut so grumbly?
Believe it or not, your stomach doesn’t only make a noise when you’re feeling hungry… and in fact, it isn’t just your stomach that grumbles.
Tummy rumbles are also known as borborygmi (pronounced bor-bor-igmi, which kind of sounds like a gurgling stomach), and are caused by muscle contractions in the stomach and small intestines. The walls of your gastrointestinal tract – the hollow passage that runs from your mouth to, well, the other end – are mostly made up of smooth muscle, which contracts and relaxes alternately to mash up the food you’ve eaten and send it down and eventually out of your body.
As the food you eat gets digested and pushed through your gastrointestinal tract, a bit of gas is also formed. This bubbles around with the food and liquid in your gut, and as alternative cycles of muscle contractions and relaxations propel all that mush through your system, you end up with all those embarrassing sound effects.
Hungry or not, here we come…
As we said, this doesn’t only happen when you’re hungry. Your stomach can rumble at any time – put your ear against a friend’s stomach and you’ll usually hear it – but the noises sound loudest when you’re hungry because the stomach and intestines are mostly empty by this stage, so there’s less stuff inside to muffle any sound.
Not sure what we mean? Imagine the sound a pair of takkies would make on their own in the tumble dryer, compared to a pair of takkies along with a few towels…
Credit: Image from Flickr/D Sharon Pruitt