The aging process is evolutionarily conserved and subject to quantitative modification by both genetic and environmental factors. Fundamental mechanisms of aging result in progressive deficits in the function of cells and organs, often leading to diseases that ultimately kill the organism such as cancers, cardiovascular disease and neurodegenerative disorders. Oxidative stress and damage to all of the major classes of molecules in cells are involved in aging and age-related diseases. The widely pursued approach of targeting disease-specific processes to develop therapeutic interventions has not had a major impact on healthspan. A more productive approach would be to target the fundamental mechanisms of aging throughout adult life so as to extend healthspan. Caloric restriction and regular exercise are two such approaches.