The average life for a player on DayZ is 49 minutes.
It used to be closer to 4 hours, but an update that removed much of the starting gear (including your first weapon) turned an already deadly simulation into a much more dangerous adventure. In a word, it's brutal.
The premise is simple. Each life starts with a character arriving on the coast of Chernarus (a 225 km2 open world post-soviet state), with nothing but the clothes on his/her back, some pain killers, a bandage and a flashlight. Beyond that there is one solitary objective: stay alive.