I also run 3-4 times per week as well as do push-ups and crunches plus various other weight training.
Not sure if I think it helps my hunting since I'm mostly a sit in one place and wait kind of hunter, but I know for a fact it definitely helps when the time comes to drag the deer out of the woods!
It definitely helps when it comes to pheasant hunting though, especially through thick brush in the sloughs.
The one area it hurts me is that I'm down 20lbs of fat from when I graduated college now that I workout regularly and I get cold a helluva lot easier than I used to. Wife likes this version better though
Also, a 5 mile run the day before season opener is about the only way to guarantee I'll get some sleep that night!
To the older/more experienced hunters out there, does the night before season opener jitters ever go away and give rise to an easy night of sleep?