WASHINGTON — US service members in Afghanistan who consumed three or more caffeine-charged energy drinks a day were prone to sleepiness and dozing off while on guard duty, according to a report.
Forty-five percent of those in Afghan combat areas in 2010 were daily users of energy drinks, some of which have the caffeine of one to three cups of coffee, the study said. The finding was published Thursday in the Centers for Disease Control and Prevention’s Morbidity and Mortality Weekly report.
About 6 percent of adolescent and young males in the US civilian and military populations drink energy drinks each day, the report said. The products, such as those made by Monster Beverage Corp. and Red Bull, can have negative side effects, including caffeine intoxication, and have been the focus of an investigation by the Food and Drug Administration.
‘‘Service members should be educated regarding the potential adverse effects of excessive energy drink consumption on sleep and mission performance and should be encouraged to moderate their energy drink consumption in combat environments,’’ wrote Robin Toblin, the study’s lead author.
Fourteen percent of service members surveyed consumed at least three energy drinks a day. They reported sleeping less, having more sleep disruptions from stress and illness, and falling asleep on guard duty and in briefings more frequently than those who had two or less of the drinks a day. They were also more likely to report sleeping less than four hours a night, on average.
Previous research found that 200 milligrams of caffeine, or one to two energy drinks, improved cognitive performance.