This is why heartbreak physically hurts.

When I last had my heart broken I got on a plane to Byron Bay, figuring if I was going to be off work and staggering around with great pathos, I might as well stagger around with a sea view.

All through the airport I had a face like a smacked arse. I could feel my features growing pinchy and tight as I trailed through the food court; the sort of face that elicits a “cheer up, darling, it might never happen,” which quickly escalates into an unpleasant exchange.

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Over at SumoSalad, I observed that stabbing sensation in the heart region – literally like a blade to the heart – and thought: “There’s got to be a biological process that’s causing this. And if there’s a biological process, then this pain just means that I’m a human being having a chemical reaction. You know – rather than it meaning that me and my disappointment are the centre of the universe.”

Sitting on the plane, waiting for the doors to shut, I got on old mate Google.

Heartache is the handiwork of the vagus nerve, which travels from the limbic system in the skull, to the chest.

The limbic system is that most primeval of zones, from which our every base urge and unconscious thought materialises. Thoughts like shag it, eat it, wail into the carpet all come from the limbic system. It’s also known as the emotional brain and the paleomammalian brain. It houses our bad memories… and also our good memories, but we’re hardly likely to be replaying those relentlessly at a time like this, are we?

During emotional upheaval, the limbic system agitates the vagus nerve, which causes a sudden drop in blood pressure and heart rate, and inflicts that feeling in the chest like heartache.

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The vagus nerve isn’t just being a dick here. It’s part of the parasympathetic nervous system, which responds to emotional stress by defusing the sense of emergency through slowing down the body – sometimes a bit too efficiently. (You’ll also observe it, going a bit overboard, when you’re anxious about public speaking – and the next thing you know you’re feeling lethargic and shaky.) On the flipside, in situations where we really need to be prepared for ‘fight or flight’, the sympathetic nervous system speeds up the heart and gets the adrenalin pumping.

From the chest, the vagus nerve continues to the gut. Dr Michael Gershon, chairman of the department of anatomy and cell biology at Columbia University, hypothesises to Scientific American that the gut is our second brain, complete with neuroreceptors. Perhaps one day we’ll even book the gut in to see a psychiatrist, one of Gershon’s peers suggests. Certainly, we should ‘trust our gut’.

Finally, in a beautiful double whammy, the gut transmits stress signals back up the vagus nerve to the heart.

So how to fix this sophisticated system? That’s right, you don’t. Well… according to Psychology Today, you can ‘stimulate healthy vagal tone’ with time and practise, but for now you just marvel at the wonder of being human and wait for it to pass.

Do this with a sea view.