What caffeine does to your body and brain | IFLScience

http://www.iflscience.com/health-and-medicine/what-caffeine-does-to-your-body-and-brain/

Many of us depend on caffeine – especially many coders.
For starters, caffeine makes most of us feel more alert and awake. But while it can keep us focused, too much can also backfire. And it also affects everything in our bodies from our digestion to our metabolism and vision.
Caffeine excites our brain cells. As a central nervous system stimulant, caffeine doesn’t just boost alertness, it can also improve your mood.

Whether you get your daily caffeine fix from coffee, tea, or a canned energy drink doesn’t make much of a difference.