The investigators have shown that undiagnosed sleep disordered breathing is prevalent for both men and women throughout the range of middle age; multidisciplinary research findings suggest that untreated sleep disordered breathing may lead to significant behavioral and cardiovascular morbidity. The relative risks are of direct application to public health estimates of: How much behavioral and cardiovascular morbidity would be eliminated if prevalence of untreated sleep disordered breathing were significantly reduced? How much reduction in sleep disordered breathing prevalence could be achieved by eliminating the modifiable etiologic factors? Should high risk groups be targeted for early detection of risk factor reduction programs?