Not sure about running, but I use a belly band for dog walks and cycling. It starts to dig into my hips around 30 or so miles on the bike, but other than the slight discomfort, it is super secure. I appendix carry for the dog walks and move the gun position behind my right hip for cycling.
When I was running (for a short lived period of time) I looked into hip water bottle carriers that had a center pocket for the gun and one or two bottle pockets but I could never find one that would fit the gun and I did not have the belly band at the time. Something like
this. I always thought it would be a inconspicuous way to carry while running, rather than a fanny pack, which also tends to bounce around.
Admittedly, I always wanted to try the compression shorts with the built in holster, but the price always made me pause. Here it is:
Concealment shorts
A note on the belly band though ... when I wear it to work, it tends to ride up from my hips to my midsection, which I imagine might occur while running, unless your wife has it secured to her waist rather than her hips. The great thing about belly bands is that they are super versatile, in that you can position them in a variety of places depending on the use.