Biology
The Fight-or-Flight Response Mediated by the Sympathetic Nervous System
Quick fact
The fight-or-flight response can trigger within milliseconds, releasing adrenaline and noradrenaline to mobilize energy stores, and it activates even before you consciously perceive the threat—your brain's alarm system works ahead of your rational thought.
Why this is interesting
Imagine you're crossing the street and a car suddenly swerves toward you. In a split second, your heart races, your palms sweat, and you leap out of the way. What just happened inside your body?