She may be on to something. I have been running since high school, more so during my time in the Corps, but have never been a good runner. Both knees have had surgery and I have only run a sub 6-minute mile once. Others I have known smoke just before and right after running and are sub 5-minute milers.
Maybe I should take up smoking...
I was a 8-min mile runner...so I was always really slow. But I reached some point in the 1990s where I could run eight to ten miles without a break.