I actually find writing to be a good way to relieve stress. Whenever something's bothering me, I like to write it down. If I need to rant, I do that as well. It helps with relieving your stress because you aren't bottling it up. Ranting out in little bits to threads designed to just be random ranting and all that help too [I like to do that in the "Message to Anyone" thread we have here in the forums; let's me say my side to another person / rant to them].
Also, I do agree with Almora with sleep. Lots of times when I feel depressed or just stressed, it gets to the point where I'm just plain tired. By that time, sleeping helps clear your thoughts [as Almora said] and also puts time between you and whatever you were stressing about. Sleep does relax.
Also, I suggest music. But not just any music - instrumentals only. They tend to be more relaxing depending on the genre you like better, the volume, and the instruments being played. When I'm studying or just plain frustrated / depressed, I listen to my instrumentals. The lack of words lets you think and feel the tone of the song more.
she runs because
that's the only thing
she can do.