"Adrenaline's effects are dramatic and unmistakable, but because this hormone does not linger in your body, its effects are also relatively short-lived. On the other hand, cortisol, the stress hormone produced by the outer cortex, has more prolonged effects on your body. If adrenaline is like the whip that drives the horse faster and faster, cortisol is like the rider's boot, digging into the flank, keeping the horse going even when it's ready to quit."