For a good overview background of "bioenergetics" (https://en.wikipedia.org/wiki/Bioenergetics) see Guy Brown's The Energy of Life: The Science of What Makes Our Minds and Bodies Work. A review at http://www.trnmag.com/Bookshelf/The%20Energy%20of%20Life.htm...
My own interest in bioenergetics came from studying Yoga/Ayurveda/Qigong/Acupuncture techniques, trying to understand their models of human physiology/anatomy and mapping them onto modern biological science.
Today with lifestyle diseases plaguing everybody i.e. "you feel drained of energy (both mental and physical) without being sick with something" it is even more important that we study our energetic pathways holistically for prophylactic health.