Exactly right, the idea is basically to force the processing that happens during that rem phase. That's done, Hartman theorizes, and I forgot the level of basi

Exactly right, the idea is basically to force the processing that happens during that rem phase. That's done, Hartman theorizes, and I forgot the level of basis in empirics he has, by doing anything that facilitates both sides of your brain working together. That's easiest done by walking, since you really are forcing both sides to communicate to facilitate the motion. Then thinking and focusing on the trauma/loss basically mimics the processing done during that rem processing.