THE SCIENCE OF CAFFEINE
It’s important to keep in mind that caffeine isn’t really giving you energy, because in reality that energy drink you’re drinking is really just blocking a signal to your brain. Adenosine stands to the side and waits to tell your brain you’re tired, while caffeine continues to occupy its position inside your brain. The longer you’re awake, the more adenosine builds up inside your brains.
Once caffeine detaches from the receptors, adenosine can bond with its brain cells, slow them down and make you feel the natural tired you were originally meant to feel, and then some. This is also known as the crash, which most caffeine consumers experience. Caffeine just puts off the inevitable inside the brain, which is why the next morning a regular coffee drinker will have symptoms of withdrawal and cause them to reach for their next cup in a cyclical effort to stay awake.