One of the central ideas in Chinese Medicine is Qi, pronounced Chi, and in Japanese - Ki. But what the hell is it, and why does it matter? This is probably the second most asked questions I get as an acupuncturist, right after "Does it Hurt?" That being said, so many people have tried to answer it over the years, I hate to rehash it again. So I'm going to quote one of my favorite books here. Between Heaven and Earth: A Guide to Chinese Medicine, authors Harriet Beinfield and Efrem Korngold said of Qi:
“That which animates life is called Qi. The concept of Qi is absolutely at the heart of Chinese Medicine. Life is defined by Qi even though it is impossible to grasp, measure, quantify, see or isolate. Immaterial yet essential, the material world is formed by it. An invisible force known only by its effects, Qi is recognized indirectly by what it fosters, generates and protects.
Matter is Qi taking shape. Mountains forming, forests growing, rivers streaming, and creatures proliferating are all manifestations of Qi. In the human being, all functions of the body and mind are manifestations of Qi: sensing, cogitating, feeling, digesting, stirring, and propagating.… It is the fundamental mystery and miracle.”
So there you have it, lol. My mentor liked to say that "Qi is function" as a concise idea, and I think that gets the point across. Your body's ability to do its job is fueled by qi. Honestly, the concept is so deep I could talk about it for hours, but I won't :) I will say that qi is not finite. Through acupuncture, herbs, lifestyle, exercise, and qigong - you can change the amount of qi in your body and increase your health and longevity! Pretty cool, huh?