What do you think of "sub-health"?

I once read from the book that a investigation hold from WHO shows that there are 5% of the people all over the world who are in disease states and 20% are really health,the other 75% are in subhealth.I think the subhealth is the status between health and disease.You don't feel well but when you see a doctor and have a examination there is nothing wrong.Do you have this feeling?Are you in the state of subhealth?How would you like to deal with this uncomfortable feeling?Or just ignore it?