Deca tends to create a lot of added fluid. There is a chance that you'll experience high level of pumps in your legs. I'm not a runner by any means. In fact, I try to not run anywhere. My body just isn't designed for moving too fast. Still, I know what it's like to try to even walk up stairs when I'm filled with water. The pumps can be so painful that I have to stop and wait for relief. So if you do want to use some deca, you might want to start with 150mg and see how it treats you. It'll take several wks for it to build up and from there, you'll better know if you can take more comfortably.