The main motivation of the article is to make health care decision makers more aware of the dynamic nature of population aging and how, in the context of improving survival and economic booms and busts, common ways of measuring it do not reflect the real financial burden of an old-age population, especially with respect to health care. A fixed age threshold is conventionally used to separate the “elderly” from the “working-age population”, usually age 65, as this has been the age at retirement for many years before recent legislative changes raising this age in many industrial countries. One could question, however, how useful fixed age thresholds are in a context of a 5-year increase in the life expectancy at age 65 over the last 50 years. Likewise, not everyone of working-age is actually employed, although over time more and more women have entered the work force or economic downturns lead to the loss of millions of jobs. Ageing indicators therefore also require more appropriate denominators. In this paper, several alternative indicators of population aging are therefore put forward that could supplement standard measurements and applied to the US.One of the conclusions of the paper is that it appears incorrect to assume that population aging itself will strain US health and social care systems as increasing health care costs are also driven by progress in medical knowledge and technology, costs of hospitalization and the increasing use of long-term care facilities. Moreover, since 1970 economic output, and even tax revenue, increased much faster than the proportion elderly (even in terms of the standard definition, i.e. ages 65+), despite economic downturns producing temporal declines.