According to the study, students who either drank alcohol and energy drinks on the same day or who combined the two at the same time wound up spending more time drinking – thus consuming more alcohol – than they would have without the caffeinated drinks. The result of spending more hours drinking raised users' blood alcohol levels to higher peaks. But because of the stimulant effects of the energy drinks, the users reported that they felt less drunk than they actually were. "This can have serious potential health impacts, for example if people don't realize how intoxicated they actually are and decide to drive home," Patrick said.