If you were a runner before PG then it shouldn't be too much of a problem. Just be sure and take care of yourself and remember that your ligaments will soften up and you may be more prone to injury. The problem is that you may not notice it so much now but in the future after your PG you may.
The other thing to consider is that your temp shouldn't get too high and your heart rate is not reccomended to increase over 140 BPM.