I'm running and have been since my late 20's. I actually think gray hair looks fabulous with some complexions. My very pale skin has a yellow (ivory) undertone and I look totally washed out with gray hair. My mom and sister have much more color in their pinkish skin and they look terrific with gray hair. I've also seen some women with very dark skin who look sensational with gray hair.
I think if you have good contrast between the gray and your skintone, it makes a big difference. I look washed out in gray clothing also. If I looked well in gray hair I would definitely do it but since it makes me look like I've been in a crypt for a month, no way.