Scientists are now pursuing the means to slow ageing in people, but there has been comparatively less effort in understanding the health and economic consequences of success. In this paper we will address the short-term (10 years) and long-term (50 years) effects of decelerated ageing on the health and mortality of future generations of older persons, as well as the economic impact on individuals and populations. We use a dynamic simulation approach based on modeling the progression over the life course of Future American based on the Future Elderly Model. The model also tracks taxes, pensions and health care costs, which allows us to quantify the fiscal consequences of decelerating aging. We contrast a number of scenarios involving the deceleration of the incidence of various health conditions and mortality.