Fight or Flight Response

When your body detects a threat or stressor, it activates a series of rapid changes to prepare you for immediate action. This process begins in the amygdala, which recognizes the danger and signals the hypothalamus to mobilize the sympathetic branch of your autonomic nervous system (ANS).

The hypothalamus then triggers the adrenal medulla (inner part of the adrenal gland) to release hormones called adrenaline and noradrenaline. These powerful hormones create several immediate physical changes: your heart rate increases, breathing quickens, pupils dilate, and certain muscles contract. All these changes prepare your body to either fight the threat or flee from it.

Did you know? The fight or flight response happens automatically—you don't consciously control it. This evolutionary adaptation has kept humans alive for thousands of years!

When the danger passes, your body needs to calm down and return to normal. The parasympathetic branch of your nervous system takes over (sometimes called "rest and digest"), decreasing your heart and breathing rates while increasing digestive activity. You might notice physical signs like sweating (to cool your body down) and shaking (as your body releases excess adrenaline).