The Evolution of Aging Theories: Why Modern Programmed Aging Concepts are Transforming Medical Research

Programmed aging refers to the idea that senescence in humans and other organisms is purposely caused by evolved biological mechanisms in order to obtain an evolutionary advantage. Until recently, programmed aging was considered theoretically impossible because of the mechanics of the evolution process and medical research was based on the idea that aging was not programmed. Theorists struggled for more than a century in efforts to develop non-programmed theories that fit observations without obtaining a consensus supporting any particular nonprogrammed theory. Empirical evidence of programmed lifespan limitations continued to accumulate. More recently, developments, especially in our understanding of biological inheritance, have exposed major issues and complexities regarding the evolution process, some of which explicitly enable programmed mammal aging. Consequently science-based opposition to programmed aging has dramatically declined. This progression has major implications for medical research because the theories suggest that very different biological mechanisms are ultimately responsible for highly age-related diseases that now represent the majority of research efforts and health costs. Most particularly, programmed theories suggest that aging, per se, is a treatable condition and suggest a second path toward treating and preventing age-related diseases that can be exploited in addition to the traditional disease-specific approaches. The theories also make predictions regarding the nature of biological aging mechanisms and therefore suggest research directions. This article discusses the evolutionary mechanics developments, the consequent programmed aging theories, and logical inferences concerning biological aging mechanisms. It concludes that major medical research organizations cannot afford to ignore programmed aging concepts in assigning research resources and directions.