Adrenaline, commonly known as the fight or flight hormone, is produced by the adrenal glands after receiving a message from the brain that a stressful situation has presented itself. Adrenaline, along with norepinephrine (more on that below), is largely responsible for the immediate reactions we feel when stressed. Imagine you're trying to change lanes in your car, says Amit Sood, M.D., director of research at the Complementary and Integrative Medicine and chair of Mayo Mind Body Initiative at Mayo Clinic. Suddenly, from your blind spot, comes a car racing at 100 miles per hour. You return to your original lane and your heart is pounding. Your muscles are tense, you're breathing faster, you may start sweating. That's adrenaline.
Norepinephrine is a hormone similar to adrenaline, released from the adrenal glands and also from the brain, says Sood. The primary role of norepinephrine, like adrenaline, is arousal, says Sood. "When you are stressed, you become more aware, awake, focused," he says. "You are just generally more responsive." It also helps to shift blood flow away from areas where it might not be so crucial, like the skin, and toward more essential areas at the time, like the muscles, so you can flee the stressful scene.
Cortisol is a steroid hormone, commonly known as the stress hormone, produced by the adrenal glands. It takes a little more time -- minutes, rather than seconds -- for you to feel the effects of cortisol in the face of stress, says Sood, because the release of this hormone takes a multi-step process involving two additional minor hormones.
