US Army researchers have linked high consumption of energy drinks among military personnel in Afghanistan with sleep problems that may cause some to fall asleep during briefings or while they’re on guard duty.
The survey, published in today’s Morbidity and Mortality Weekly Report, reported responses from 988 men in Army and Marine combat units deployed in Afghanistan in 2010. Survey questions addressed experiences and behaviors during deployment and combat, including stress, trouble sleeping, daytime sleepiness, and—for the first time—energy drink consumption. The drinks are available to service members in military dining facilities and in convenience stores.
About 45% of the service members surveyed said they had at least 1 energy drink a day; about 14% said they drank 3 or more a day. In comparison, about 6% of young men in civilian and military populations have energy drinks every day, the researchers noted. “The fact that nearly half of deployed service members were drinking at least 1 a day was surprising,” lead author LCDR Robin Toblin, PhD, MPH, of the Walter Reed Army Institute of Research, said in an e-mail.
The main active ingredient in energy drinks is caffeine, the investigators noted. Leading brands of energy drinks contain about 80 to 160 mg of caffeine, the same as in 1 or 2 cups of coffee. But some brands contain up to 500 mg of caffeine.
Men in the survey who had at least 3 energy drinks daily were more likely to report sleeping 4 hours or fewer per night than men who had no energy drinks or only 1 or 2 a day. Trouble sleeping because of combat stress, stress in their personal lives, and illness was significantly more likely in men who had 3 or more energy drinks a day. However, energy drink consumption didn’t affect sleep disruptions attributed to sleeping conditions, fast-paced combat operations, nighttime duties, or recreational activities.
The men who had at least 3 energy drinks a day also were more likely to fall asleep while on guard duty, and they were almost twice as likely to fall asleep during briefings. No accidents or mistakes that affected a mission occurred because of sleepiness. But Toblin said falling asleep on guard duty or during a briefing “could lead to missing critical intelligence in a combat zone, so the critical message is that energy drinks should be used in moderation.”
The researchers said their survey doesn’t show that energy drinks actually cause sleep problems and that it isn’t clear whether service members who have trouble sleeping turn to energy drinks to stay alert or whether high consumption of energy drinks disrupts sleep. Toblin said the military is testing a program to educate service personnel about caffeine intake, specifically from energy drinks.