Negative Gamer writes:
"The paper, published in Acta Paediatrica, used 19 boys aged between 12 and 15 and told them to play one violent, and one non-violent game for 2 hours before bed. Measurements of their heartbeat and movement were measured whilst they played, and during the following night of sleep."
NG have essentially a nice translation of the report from technical talk (though the link to the report is given) into stuff we can understand.
"So there you have it, violent games clearly have a different impact on the gamer, but not on the quality of their sleep. Saying that, if you want to make getting out of bed easier on a Monday morning, don't play Manhunt."