Welcome Midnight! Yay for black cats! I hope you have lots of happiness together.
I, too, never realized you could close a cat out of a room
I guess I never needed to. My avatar kitty, Archie, never liked big movement or loud noise. My "bigger" workouts are in the basement, so he never bothered me. I do yoga and qi gong type of workouts in the spare bedroom, and he would often come visit me in there. Shavasana frequently involved him lying on my chest, our faces inches away from each other
I said goodbye to Archie in March, and in July adopted two new adult kitties, two weeks apart, from different rescues. Now there are times when I'm doing cardio and I'll turn around to find a kitty staring up at me. One time, during a sidestep/hamstring curl move, I managed to kick one. They are both very stealthy and curious (Boy kitty has recently started to explore all the kitchen cabinets). I've learned to be more careful. I'm just afraid someday I'll be on the spin bike and one will try to bat the wheel.
My yoga form has suffered since they showed up. Boy cat can't sit still. He winds himself around my legs and arms and gets underneath me. Girl cat just likes to sit and stare, so she makes herself comfy on the mat and doesn't move. I've done practices half off the mat.