Is watching England in the World Cup bad for your health?

As kick-off approaches I start breathing into a device that looks like a child's spinning top to record how quickly I'm breathing and how much carbon dioxide I'm breathing out.

By this point I'm starting to look like an extra in a low-budget Star Wars parody – and we are definitely the pre-match entertainment in a pub which is now heaving.

But the gear should allow us to monitor how my body changes – second by second - over the course of the Croatia match.

And as the referee gets the game under way, I am buzzing.

"I think tonight is going to be a real humdinger and that's great for us," says Bailey.

"I want to see a stress response, excitement, emotional anxiety, fear, shouting, forgetting to breathe, perhaps breathing too much, all of the above."

The readings in the opening moments show my heart rate is around 54 beats per minute, and my blood pressure 115 over 75.

"Everything is relaxed, despite the fact there are about 500 people staring at you," Bailey jests.

He was right to predict a humdinger – it was a six-goal thriller with highs and lows.

We had early drama. A Kane penalty… a guaranteed goal surely… but no, it's saved… wait… the Croatia keeper had strayed off his line and the referee orders a retake… Kane places the ball down again… shoots… GOAL!!!

I, and the rest of the crowd, are cheering with joy. But then comes the disappointment as Croatia equalise, before we take the lead again only to squander it and go in at half time with the match evenly poised at 2-2. It's an emotional rollercoaster - and the perfect conditions for the experiment.