Key to understanding Juju is the concept of subtle energy. Recognized by many traditions and cultures as a critical component of existence and health, the term 'subtle body' refers to parts of the body that are not easy to measure with regular western medical equipment but can be quite obvious when observed from a different perspective. If you have noticed in your body a physical response to a mental or emotional situation, you felt the subtle body. The subtle body permeates and expands beyond the physical body. It is affected by all kinds of stimuli: emotions, food, breathing, exercise, and the environment-including our extraterrestrial environment. Subtle energy acts on the body in an infinite combination of ways but its essential nature can almost always be categorized as one or a combination of the five essential elements of juju.