Fright in the flesh
Alarm strikes your body within seconds of recognizing a threat. Here’s what’s going down.
Before you consciously process a problem, this almond-shaped brain region activates and begins to amp up the sympathetic nervous system’s fight-or-flight response.
2 Hippocampus and frontal cortex
The rational centers of our brain kick in, analyzing whether the perceived visual or auditory input shows a true danger.
3 Cardiovascular system
Stress hormones increase your heartbeat and breathing rate while dilating the tiny airways in your lungs. This allows more oxygen to reach your muscles.
4 Endocrine glands
Signals from the amygdala hit the hypothalamus, which starts a cascade of activity throughout the endocrine system. The result: a surge of adrenaline and cortisol.
5 Gastrointestinal system
Fear really can make you poop your pants. That and retching may be side effects of shrinking blood vessels in the GI tract—diverting resources to give you strength.
6 Musculoskeletal system
Endocrine signals push glucose and other energy-storing molecules out of reserve and into the blood, which rushes in to fuel muscles should you need to escape or fend off a threat.