In yoga, we look at the human body as five sheaths. The first sheath is called annamaya kosha or the “food body,” because what you call as the physical body is just a heap of food. The second sheath is called manomaya kosha or the mental body. These two layers can only function in connection with the third dimension, the energy body or pranamaya kosha. You can compare this to computers today – there is hardware and software, but by themselves they cannot do anything unless you plug the computer into quality power.
Pranamaya kosha is the dimension in which most of the yogic practices function. If you keep your pranamaya kosha in perfect balance and fully activated, there can be no such thing as disease either in your physical or mental body. Keeping the energy body in full flow is not about doing healing or things like that. This is about going to the foundations of your energy system and activating it in a proper way by building a foundational yogic practice that establishes your energy in such a way that your body and mind are naturally fine.
~Sadhguru