Shen in Chinese Medicine refers to the consciousness in a large sense. It is further divided:
Lower consciousness: the automated survival instinct, the biological will to live. It is often referred to as animal instinct. The feeling for the need to eat, to reproduce, to protect your body from harm (cold, fire, water, fall, etc…) It is also that voice in your head that tell you to get out of a dangerous place or to take a different route.
Normal consciousness a.k.a. Monkey Mind: the acquired emotional response to your environment. What you learned from your experiences and those of others. The use of your emotions, positive and negative, to communicate with others and yourself. Basically all of your thought. Where there is a thought, there is an emotion.
Higher consciousness: being conscious of our consciousness. Feeling connected to the infinite universe and everything in it. This is the state of meditation, of tranquility, from which you have no thought but can feel everything as they are, without comment/ judgment.
The level of higher consciousness is what we are looking to develop during Qigong practice. It is easy to attain it. It is instantaneous. But to be able to keep it for a period of time require training. Not training in developing this higher consciousness but in quieting your Monkey Mind. Once the mind is calm, the higher consciousness manifests itself.