
It's not a new theory......
We know from endocrinology that our hormones engage when watching sports, as they do in the presence of any competition: testosterone, adrenaline, cortisol, and oxytocin are all active in fans.
And articles like this, "Our brain on sports"
.. https://grantland.com/features/this-your-brain-sports/
I've looked into this before to try and understand why I'm not interested in sports to the same extent as some people are when it might help a bit with the job. I was trying to learn how to be more interested.