Science
How does adrenaline work?
Adrenaline works as the body's emergency hormone, flooding your system in moments of fear or excitement to prepare you for action. It speeds your heart, sharpens focus, and releases energy — the 'fight or flight' response.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how adrenaline works.
Step by step
- 1It's released by the adrenal glands when you sense danger or stress.
- 2It raises heart rate and blood pressure to pump more oxygen.
- 3It releases stored sugar for a quick energy boost.
- 4It widens airways and sharpens the senses.
- 5It's the core of the 'fight or flight' response.
Frequently asked questions
- What does adrenaline do to the body?
- It speeds the heart, raises blood pressure, frees up energy, widens airways, and heightens alertness — readying you to fight or flee.
- Why do you feel a rush of adrenaline?
- Your brain detects a threat or thrill and signals the adrenal glands to flood your blood with adrenaline within seconds.
- Why do hands shake during an adrenaline rush?
- The surge primes muscles for sudden action, and that extra readiness can show up as trembling when you don't actually move.