Teens who played a relatively violent video game before bed took only slightly longer to fall asleep than those who watched a relaxing nature documentary, according to a preliminary study reported in the BBC. In the study, researchers from Australia recruited 13 males aged 14 to 18 with no existing sleep problems. One night, they played Call of Duty 4: Modern Warfare for 50 minutes while in bed. On a second night a week later, they spent an equal amount of time watching March of the Penguins. Three fell asleep to the movie while none fell asleep during the video game. Most who played the game were asleep within 7.5 minutes, only four minutes longer than during the documentary.