Mark Fitter said this quote

“ Elza needed challenges in her life, needed to be occupied. Without walls to climb or windmills to attack she was the type of person who became depressed. She knew this. The feeling lived inside her somewhere - probably nestled close to her solar plexus. Yes, it seemed like that was the case. She felt it right in her chest. So, to escape dwelling on her anxieties - which she was prone to do - Elza lived in a state of perpetual movement. If she slowed down or was obstructed, even for a moment, she would suffer being left alone with herself, and then all would be lost. ”