Feeling tired lately? Has the doctor said he can’t find anything wrong with you? Perhaps he sent you to a hospital, but all the advanced equipment there shows that there is nothing wrong.
Then consider this, you might be in a state of subhealth（亚健康）.
Subhealth, also called the third state or grey state, is explained as an indefinate state between health and disease. According to an investigation by the National Health Organization, over 45 per cent of subhealthy people are middle-aged or elderly. The percentage is even higher among people who work in management position as well as students around exam.
