Does coffee really keep you awake?!

Does coffee really keep you awake?

Can someone explain exactly how coffee keeps you awake and alert?

thanks

It's not the coffee itself, but the caffeine in the coffee that keeps people awake. The caffeine is a stimulant and works by causing the adrenal glands to increase their production of the body's natural steroids. These steroidal compounds are the same ones that the body produces in fight-flight situations, and they have an energizing effect. When you have larger than normal quantities of the fight-flight substances in your body, then you are more able to stay awake and alert.