Adrenaline

body chemistry · fight or flight · hormones · survival

Your body's rush. Adrenaline is a hormone made by two tiny glands on top of your kidneys called the adrenal glands. When you're scared, excited, or need to act fast, your body releases adrenaline into your blood.

Supercharges your muscles. Adrenaline makes your heart beat faster and pumps more blood to your muscles so you can run, jump, or fight if you need to. Your hands might shake and your breathing gets faster too.

Widens your pupils. When adrenaline kicks in, your pupils get bigger to let in more light so you can see better. This is why your eyes feel wide open when you're nervous or thrilled.

Boosts your energy. Adrenaline makes your body release sugar into your bloodstream so your muscles have fuel to move super fast. This is why you feel an instant burst of energy.

Found everywhere. Adrenaline isn't just in people and animals, it's even been found in a plant called Scoparia dulcis that grows in Vietnam, showing how common this powerful chemical is in nature.