The guy at the beginning of the article consumed only ~600mg of caffeine, but he consumed between 7,000 and 8,000 mg of taurine which is over 2x safe daily consumption[1]. I don't think that drinking 600 mg of caffeine is good for you, but I don't think it's the primary culprit for hospitalizations. I'm thinking the other ingredients in energy drinks, such as taurine and guarana, play a major role.

Here's an interesting quote from a recent Atlantic article[2]: "Still, despite the fact that a Starbucks venti coffee has three times as much listed caffeine as a can of Monster, some people swear they're more wired after drinking an energy drink. That may be because of the extra caffeine in guarana. Energy drinks can advertise that they have the same amount of caffeine as a cup of coffee; but when you include guarana, they have a much stronger stimulant effect."

I found this chart from the Seattle Times comparing stimulant levels in energy drinks[3]. Not only does Monster have 160 mg of caffeine in each can, it also has 5,000 mg of guarana and 2,000 mg of taurine. That's a lot of stimulants for one can. I would be interested in seeing more in-depth studies on guarana and taurine.

[1] According to the Mayo Clinic, the recommended maximum daily intake of taurine is 3,000 mg (http://www.mayoclinic.com/health/taurine/AN01856)

[2] http://www.theatlantic.com/health/archive/2013/01/how-much-c...

[3] seattletimes.nwsource.com/news/health/links/energydrinkchart10.pdf