The catabolic - anabolic cycling hormesis model of health and resilience.

A major goal of aging research is to identify ways of extending productive and disease-free lifespans. Here we present the catabolic - anabolic cycling hormesis (CACH) model for optimizing health. The CACH model is based on the concept that cells and organ systems respond to catabolic challenges in ways that bolster their resilience and that an anabolic recovery period is required to effectuate the benefits of the catabolic challenge. As two prominent real-world examples we highlight the literature on the molecular and cellular mechanisms by which physical exercise and intermittent fasting bolster cellular and organismal performance and resilience, and suppress disease processes. Over periods of weeks and months the CACH of exercise and fasting promote optimal health. The hormesis concept is integral to the CACH model and predicts an upper limit to the beneficial effects of catabolic - anabolic cycling that reflects a limit of biological plasticity. This paper extends the hormesis model of health by proposing that 1) it is comprised of two complementary phases: catabolic (adaptive stress responses and conservation of resources) and anabolic (growth and plasticity) and, 2) that CACH is metabolically integrated, quantitatively flexible and dynamically regulated. This model has important implications for future basic and translational research in the fields of aging and related disease processes.