Honestly, if Mariah Carey showed up for a workout wearing one of your designs, you'd freak out about it and probably bust out an impromptu a cappella version of "Fantasy" or something. No one is immune to the glow of Mimi's attention.
Rihanna's line for Puma includes some choice footwear that isn't exactly treadmill-friendly. Carey appears to be a fan of the stilettos with the Puma strip, especially, as she was photographed wearing them — and fishnets, so her version of athleisure — at the gym.
MTV Cribs fans will remember Carey's iconic episode, in which she invites us in for a bubble bath and heads to her fitness center to take on the StairMaster in heels. Trends may come and go, but Mimi's routine is so iconic there should be an exhibit in the Smithsonian dedicated to it. (Wouldn't be surprised if Rihanna agrees, TBH.)