Side note: This is really beautiful.
There wasn’t ever a time when she relaxed. In fact, deep breaths made her feel caged – her lungs expanded with air and yet they didn’t fill all the way and when she tried to exhale, it was work. The air hung in her lungs like the pause on a backswing and then it was pushed out too quickly. Too fast, until the lungs were empty and waiting again. It was exhausting.
She really had to concentrate for it to work, and then that wasn’t very relaxing at all.