Hypothesis: interventions that increase the response to stress offer the potential for effective life prolongation and increased health.

In the last decade it has become evident that many laboratory manipulations, both genetic and environmental, can lead to significant life extension. All or almost all of the observed life-extension phenotypes are associated with increased resistance and/or ability to respond to environmental stress. These observations show dramatically that life span is not maximized. We suggest that latent within many species-perhaps even humans-is the ability for large increases of life expectancy. The striking correlation between the increased stress resistance of all long-lived mutants in C. elegans and other species and the increased resistance of dietary restricted rodents to environmental toxins is consistent with an evolutionary conservation of a life-span maintenance/environmental stress resistance program. We suggest that it may be possible to develop methods for life extension in mammals, including humans, using relatively straightforward manipulations, such as drug treatments. It should be obvious that these findings have tremendous implications for human society at large, and we suggest that the implications of these findings should be explored.