Deficiency of qi, in traditional Chinese medicine, refers to the pathological phenomenon resulting from the deficiency of vital qi or exhaustion of
promordial qi. Unbalanced food and heavy labor may harm the spleen and hurt vital qi.  As a result, the person will feel tired in his limbs and will not want to eat. When promordial qi is hurt, the person will suffer from dizziness,  soreness in the waist, and short of breath. Deficiency of qi in other internal organs may occur as well.

1. In cold weather, people should stay at home just like the door post which stays in the mortar to preserve yang qi.
2. If you live an irrational life, your energy will drift away and yang qi will not be preserved.
3. In summer the heat may hurt you. You will perspire and feel short of breath when in a fret. That indicates the heat has entered your internal organs.
4. Although you may not feel vexed, you speak a lot and your body is hot like a burning coal. It cools down after you perspire. This indicates that you've been burt by the summer heat.
5. If you are hit by the evil damp, your head will feel heavy and distended as if it were wrapped in something. If not treated in time, your muscles and tendons will be harmed and you will suffer from flaccid paralysis.
6. Deficiency of qi also may cause edema of the limbs. This is because the yang qi is lost.
Also learn more in the article Physiological Functions of Qi.