Energy drinks may disrupt sleep in combat troops

Here is article about energy drink consumption by our soldiers. The results showed that those soldiers who consumed more energy drinks also reported less sleep at night and more daytime sleepiness. The article implies that the energy drinks are somehow responsible for the reduced nighttime sleep and daytime sleepiness. That doesn't seem likely to me. More likely is that the soldiers are sleep deprived from other sources, like being in combat! They are tired the next day and reach for the energy drinks to help them make it through the day, not the other way around.