If you're not used to large amounts of caffeine and sugar, energy drinks can quickly put you into overload. I've seen people get the shakes, break into a cold sweat, have anxiety attacks, breathe like a freight train, and even get chest pain. I've cut way back on the caffeine I consume so that even a 12 oz diet Coke makes me very alert and mildly buzzing for a couple hours.

I'm not going to preach for or against energy drinks, just know what you are drinking and pay attention to what your body is telling you.