This thesis questions the idea that; quantified self technology can make us understand our bodies better and facilitate a healthy relationship with the body. Instead, it proposes that a healthy relationship to the body is developed through technology that facilitates a somatic practice, involving the bodily experience in the interpretations of the data. This is achieved by bringing in values inspired by the practice of mindfulness as an alternative to the existing design values promoted in technological solutions dealing with the body. I have designed a first prototype, Inner Mirror, which explores adolescents’ body relationship through screen-based visuals. Inner Mirror detects adolescents’ arousals to visualize their emotional changes in abstract representations that they are invited to connect to specific emotional experiences. The process of designing Inner Mirror will be described thoroughly in the paper. The process was a continuous negotiation between the ideas and values that I brought into the project and the adolescents’ worldview. This is described through a first-person perspective and a participatory design approach. Two school classes of 43 adolescents (between 13 to 14 years old) have participated in the project through three workshops. In the end, I test the prototype in two different settings: on myself, adopting the first-person perspective and together with the adolescents. Finally, three concepts that emerged in the design work are evaluated to suggest a direction for future work.