Energy is blended with our life. “Life-force”, Chi, or Prana, in fact, is the 4th state of matter after solid, liquid, and gas. It is so physical and so ordinary that we often take it for granted. Energy is just more refined than what we already know about the physical matters. Its subtle nature makes energy intangible for the ordinary senses. However, there are many people with a more sensitive nature that can feel, see, and experience the existence of energy. For sensitive eyes, it looks like a luminous field of light, surrounding the physical body and interpenetrating it.
Based on the Law of Correspondence, what affects this energy field, affects the physical body too; that is also how dirty energies, thoughts, and emotions develop into poor physical health.
You may also have heard so many times about 80% of diseases being psychosomatic, and the rationale behind this fact is the existence of the energy body and the energy centers, also known as the chakras.