Part 3/12:
Remarkably, this stress response machinery has been indispensable for human survival over millennia. Without cortisol, our ancestors wouldn't have succeeded in escaping predators or securing resources. The design of this system is so efficient that it's worth appreciating it as an incredibly advanced biological machine, optimized for rapid response to threats.
The Two Cycles of Stress
However, this machinery has a caveat: it operates through two interconnected cycles. The first is the initial stress response—cortisol flooding the bloodstream, preparing the body for action. The second is a feedback loop that determines whether the stress state persists or subsides.