That's really the first time it's been like that though, no?
It's most commonly know that Banner changes when he becomes angry. That's how I've always understood it.
I mean, I've never heard him say, 'Don't make my pulse fast. You won't like me when my pulse is fast.'
So a while back, a very thoughtful and observant poster made an important suggestion: maybe Banner just thinks the change is related to his pulse rate and not to other biological contributing factors, such as release of adrenaline and norepinephrine combined with a disturbed emotional state. Sure, the movie suggests that he can't embark on Liv Tyler disneyland, but maybe there is more to it to explore in a sequel.
I see what you did there!
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