A auto-run macro is not possible but a sprint macro yes.

/ac "Sprint" <me> (quotes and <me> should not be needed but I always put them)
/wait 30 (or 31 to compensate lag and the sprint animation - I don't remember how much I have put in my macro )
/ac "Sprint" <me>
/wait 30
.....
I think you are limited to 15 lines for a macro
Using another macro will interrupt the sprint macro.

The wait command will change in the future(dev post) so it will look like
/ac sprint <wait.30>
/ac sprint <wait.30>
....