In her TED talk, Sarah Gaer discusses the concept of soul exhaustion, a feeling that goes beyond physical exhaustion and seeps into the very essence of who we are. She reflects on how her childhood experiences left her feeling exhausted, beat up, and worn down, and how the suicide of her best friend highlighted the deepest form of soul exhaustion. Through her story, she inspires listeners to reflect on their own experiences and understand the importance of taking care of their souls.