Epinephrine’s major action is in its role as a hormone. Epinephrine is released by your adrenal glands in response to stress. This reaction causes a number of changes in your body and is known as the fight-or-flight response. | Cleveland Clinic

How Epinephrine works | LifeOfADoctor

Adrenaline — also called epinephrine — is a hormone and neurotransmitter your body releases in response to stress, excitement, or danger. It’s part of the “fight-or-flight” response. Here’s what happens when adrenaline kicks in: • Heart rate increases – pumps more blood to muscles. • Pupils dilate – better vision. • Airways open up – more oxygen intake. • Blood sugar rises – more energy for muscles. • Pain perception drops – so you can push through. Basically, adrenaline turns your body into a h