What is sub-health and what is the standard of health?

Sub-health is a state of low physiological function between health and disease, which is called sub-health state, also called gray state, and is a process from quantitative change to qualitative change. Sub-health has no organic lesions, but functional changes. Sub-health and AIDS go hand in hand, and its harm can not be ignored, which should be highly valued. The performance of sub-health: one more and three less. Fatigue, memory loss, vitality loss and adaptability loss. For reference.