I'm assuming that the GDP is some sort of measure of the health of the economy-- that's why people are concerned with it. The health of the economy seems to me like rather an approximate sort of thing.
GDP -- Gross Domestic Product -- basically means the sum of the value (in the economic sense) of all goods produced domestically during a given period, e.g. a year.
If you want to measure the "health of the economy", that's quite different. You'll have to define what do you mean by that expression and then decide which measurements do you want to consider. For example, some people might consider the unemployment rate to be one those measurements, or, say, the Gini index, or the median income, or... the possibilities are endless.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.