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

"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.

At half-time we assess how our fellow England fans' bodies are coping.

Ollie, 23, says his heart is going "50 times a second" and he might "keel over and die" from the stress, while Tim, 38, says he needs more England goals because "currently it's pretty bad for my health".

Beth, 27, is more chilled: "I see my friends, I have a shout at the TV, I have a beer".

Unlike most of the crowd here, we're doing the experiment sober in case the depressant effect of alcohol influences the results.

The second half is far calmer. England are dominant and tension turns to jubilation as we win 4-2.

Damian and I head outside to discuss the results in the unofficial "post-match analysis beer tent".

"Your physiology is performing beautifully," he tells me. "We see a stress response whenever something exciting happens".

The first goal of the match - Kane's penalty – is a good example.

My heart rate cruised through most of the match in the low to mid-50 beats per minute but "literally within half a second" of Kane scoring my heart rate rose to 69 beats per minute.

Blood pressure went up too and there was less carbon dioxide in the air I was breathing out suggesting I was "hyperventilating a little" says Bailey and that led to a "reduction in blood flow into the brain".

And my saliva tests show levels of the stress hormone cortisol went from a chilled out 4.19 nmol/L before the match to a slightly stressed 5.15 nmol/L at the final whistle.

Altogether this shows a classic stress response in the body. When we talk about stress we often think about "bad stress" from work or exams or juggling-a-billion-things-at-once.

But Bailey says you can have good stress too. From an evolutionary perspective "stress is what keeps us alive" by activating our flight-or-fight response.

Bailey says my readings are like a "mild form of exercise" - just without burning any calories.

"You are elevating things that I would interpret as good for you, and you're recovering very quickly".

So there you have it, watching England is good for my health, however, there is a but. The same won't be true for everyone.

I have a relatively low stress response that "is almost Special Forces... you really are a cool customer I must say", says Bailey.

"You keep yourself physically active, you keep yourself in good shape."

If the science says I'm fit with nerves of steel, then I can hardly argue can I?

But the same won't be true for everyone as some people are "really sensitive" to stress, says Bailey, and their heart rate could shoot up by 50 to 60 beats per minute.

If you already have a heart or brain condition then the stress could "in extreme situations" trigger a heart attack as the blood vessels tighten, pressure goes up and the blood becomes thick "like honey", he says.

In some people, changes in breathing can alter blood flow to the brain, causing them to faint from the stress.

So I'll leave it to you to decide if watching England is good for you. But as far as my body's concerned… bring on the next game!

Additional reporting and video journalism by Jamie Moreland.