This is a multidisciplinary investigation of life style and physiologic changes induced in subjects over 60 years of age by eight months of low or moderate intensity exercise. Variables to be assessed include myocardial performance, hematological parameters, catecholamines, GIP, glucagon, insulin pancreatic polypeptide, C peptide, serum lipids apoproteins, cardiac electrophysiology, blood pressure, maximal oxygen uptake, muscular strength, life satisfaction, sleep quality and quantity, and mental function status.