[kyzerjose]

Nice bit of "nut shell" physiology.

The interesting thing about the human body is its need for balance or maintaining the status quo. As in Physics, for every action, there is an equal and opposite reaction.
When your endocrine system dumps in response to one stimuli, a different brew of chemicals is released shortly thereafter to counteract the first event.
Basically, that's why you can feel like crap physically once the original "threat" has passed.
We can train our body (mind) to react in a different manner but it's not easy.
Dr. Al makes some interesting points in his PoP book. As I recall, he maintains that playing poker well requires the mind to make decisions that are counter-intuitive to our natural tendency to take the path of least resisitance.
I believe he mentions Law Enforcement & Military Pilot workers as two groups who are naturally wired to play poker effectively.