A fundamental difference between Eastern and Western medicine is that many of the Eastern traditions include practices that help one to develop and achieve optimal health and wellness before the onset of disease, infection and emotional problems. Prescribing Qi Gong to prevent and cure illnesses of the body, mind and spirit is quite typical for Chinese medicine practitioners, but anything similar is almost unheard of in Western healthcare.
In Chinese medicine and philosophy, Qi is thought of as “the natural force which fills the universe,” and while there are many ways of defining Qi, it may be generally thought of as any and all types of energy which are “able to demonstrate power and strength,” including the power to animate objects with life. 
“It is known that all diseases arise from the upset of qi: Anger pushes the qi up, joy makes the qi slacken, grief disperses the qi, fear brings the qi down, terror confuses the qi, and anxiety causes the qi to stagnate. Anger harms the liver, joy the heart, anxiety the spleen, grief the lungs, and fear the kidneys.” – The Nei Jing
Primarily handed down from generation to generation by word of mouth and in actual practice, not in written texts, the ancient Chinese practices of Qi Gong can vary wildly between teachers and schools of thought. It can be many things including physical exercises (both standing and seated), forms that resemble martial arts, breathing exercises, visualizations and, or, meditations.
The system is incredibly diverse, however, the science behind the flow of energy in and around the body has been well documented for thousands of years, and many schools of thought are in concurrence about many of the basic and even more esoteric concepts and terms involved. Among the most important concepts in Qi Gong training is an understanding of what are known as ‘San Bǎo’ (三寶), or, The Three Treasures.
Jing (Essence), Qi (Internal Energy), and Shen (Spirit), are the Three Treasures, The Three Foundations, or The Three Origins, and are the root of life.
“In Qi Gong training, a practitioner learns how to ‘firm his jing,’ and how to convert it into Qi. This is called ‘Lian Jing Hua Qi,’ which means to ‘to refine the Jing and convert it into Qi.’ Then he learns how to lead the Qi to the head to onvert it into Shen. This is called ‘Lian Qi Hua Shen,’ which means ‘to refine the Qi and convert it into (nourish) the Shen.’ Finally the practitioner learns to use his energized Shen to govern the emotional part of his personality. This is called, ‘Lian Shen Liao Xing, or ‘to refine the Shen to end human (emotional) nature.'” -Dr. Yang, Jwing-Ming 
Jing means a number of things and as a word it can be used as a noun, a verb or an adjective. It is considered the essence, the original source from which a thing is made, and also the refining process by which a person’s essence is polished or sharpened. Jing is the energy given to you at birth that enables you to grow and to develop strength. Many believe it to be the most important part of a you because it is considered to be the root energy to Qi and Shen. Learning first how to conserve and firm your original Jing is critical to Qi Gong training.
Qi is, again, the energy that fills the universe. There really is no clear explanation of how it works or of the vessels in the body which provide for the flow of Qi, but it can be distinctly felt as an energizing and healing force that can be manipulated and moved by the mind and body. Qi supplies the energy your organs need to function, and much like electricity in a factory that provides differing levels of current for different machines, the flow of Qi must be consciously regulated in order for the body to function optimally.
Shen is more difficult to describe in Western terms, but it may be considered to be spiritual or mental energy, the supernatural, the divine, the immortal soul, or the cosmic energy that drives and elevates consciousness. Shen is also the emotional mind, the part of us that governs our mood and behavior, the force that collects and utilizes wisdom. In order to raise your Shen you must first nourish and fill the brain with Qi, which is how dedication to the practices of Qi Gong can lead to a very real spiritual awakening.
“Buddhists and Daoists believe that when you are alive you may use your Jing and Qi to nourish the Shen… When this is built up to a high level, your will is able to lead it to seperate from the physical body even while you are alive. When you have reached this stage, your physical body is able to live for many hundreds of years. People who can do this are called ‘Xian,’ which means ‘god,’ ‘immortal,’ or ‘fariy…’ The ‘Xian’ is a living person whose Shen has reached the stage of enlightenment or Buddhahood.”-Dr. Jwing-Ming Yang, The Root of Chinese Qi Gong: Secrets for Health, Longevity and Enlightenment
The roots of depression, anxiety, fear and other negative emotions are found within the energy body, and in our modern world of stress, over-work, over-stimulation, and constant hustle, the nervous and emotional systems of the body are the first to breakdown.
Qi Gong is itself a true treasure for those seeking physical and mental wellness, as well as happiness in our short, beautiful lives. It is the most practical method of strengthening and building life force energy within the body, mind and spirit, and catalyzing meaningful personal transformation. The presence and experience of Qi is universal to human beings and can be directly experienced with Qi Gong.
Anyone can develop the presence, awareness and sensitivity to come to know The Three Treasures. And what a treasure it is to see a happy, healthy person.