There is increasing focus on the quality of children's sleep
Playing a video game before bed appears to have only a mild effect on how long it takes a male teenager to fall asleep, a preliminary study suggests.
Those who played a relatively violent video game took only marginally longer to fall asleep than those who watched a relaxing nature documentary.
The Journal of Clinical Sleep Medicine study pitted Call of Duty 4 against March of the Penguins.
There is little scientific data on the effects of video games on sleep.
But anecdotal evidence has long suggested that playing such games at night could have a detrimental impact on sleep because the stimulation keeps one awake even after the game has ceased.
To test the theory, researchers at Flinders University in Adelaide, Australia, recruited 13 males between the aged of 14 and 18 with no existing sleep problems.
Soldiers v penguins
On one night they sat beneath the covers playing Call of Duty 4: Modern Warfare for 50 minutes - a game in which the player takes on the role of an SAS recruit among others carrying out various violent missions.
On a second night a week later they spent an equal amount of time watching March of the Penguins, the award-winning French documentary which follows the yearly journey of the emperor penguins of Antarctica across vast swathes of ice to their breeding grounds.
Three fell asleep while watching the film, while none dozed off while playing Call of Duty.
The majority of the teenagers did take longer to fall asleep after playing the video game, but most were asleep within seven-and-a-half minutes - only four minutes longer than when they watched March of the Penguins.
"We purposefully chose a very tranquil film to contrast against the very stimulating effect of playing a violent video game in the hope of producing the greatest effect on sleep," said Michael Gradisar, a senior lecturer in clinical child psychology who led the research.
"We were surprised that playing the violent video game did not lead to a much longer time taken to fall asleep."
However he acknowledged there were limitations to the small study, notably that very few teenagers who played would limit their playing time to just 50 minutes a night.
"With greater time invested there could be a greater emotional investment in the game. What happens to the teen's virtual character could begin to evoke feelings of anxiety or frustration that could have larger effects on their sleep."
And however tranquil March of the Penguins may be, some sleep experts urge no screen activity before bed - be it computer, game or TV.
There has been increasing focus on the quality and length of young people's sleep, in part because of the impact on concentration but also amid mounting suggestions that poor sleep may be contributing to obesity levels.
A French study published this week found that young men ate 25% more calories a day when they had four hours of sleep the night before compared to when they had slept for eight hours.