I don't think playing that music will slow down your run speed, that's mostly all I play.
One thing, if there is a certain point where you notice it slows down, work it out! Make sure you're staying relaxed. A lot of musicians get stressed when they keep trying to work out a problematic section and start tensing up, that will hurt your speed a lot.
One thing that I do, no lie, I stop every so often and go into a prayer and meditation session. Keep returning to that. If you start getting frustrated, get away from the instrument. This will help you stay relaxed.