Excellent article and explanation of what Qi is.
"Chi, often written as Qi (pronounced “chee”) could be described as a type of bioelectricity and is the life force in and around us. It cannot normally be seen without the aid of Kirlian photography, but it can be felt and its effects can be seen. Numerous cultures describe a matrix of subtle energies that support and animate the physical body. This energy is called Chi in Chinese, Ki in Japanese, Prana in India and Tibet, and Nefesh in Israel. Sufis call it Baraka, Christian mystics call it the Holy Spirit and the ancient Greeks called it Pneuma. Hahnemann, father of homeopathy, referred to it as "vital force," and in chiropractic it is called the "innate intelligence." Our bodies are composed of a series of energy systems which are interwoven and superimposed. The correct functioning of these systems forms the basis of our health. Energetically charged fluids are pumped through the lymphatic system, the blood circulatory system, interstitially, through the bone marrow and spine, around the brain and so on. The Chi flows through a system of meridians which are like channels within the energy body. Chi is all around us in the environment and inside us; our body is dependant upon this Chi to continue functioning.
We obtain Chi from the air, food, water, the Sun, warm places, the moon, the Earth, stars, and several other places in the environment. When we are born we also have an abundant supply of Chi stored our abdomen, which will usually deplete gradually through the course of our lifetime if we do not replenish it by way of Chi Gung exercises!