The Bogalusa Heart Study, an investigation of 8,000 children, has compiled a large data bank on cardiovascular (CV) risk factors in children during the past 12 years. Precursors of heart disease begin at a young age, with many children already possessing one or more known clinical risk factors--hypertension, obesity, and adverse lipoprotein changes. Having obtained data examining the determinants, distributions, interrelationships and trends over time for CV risk factors, a foundation was provided to address additional questions directed toward intervention strategies. "Heart Smart" is a comprehensive, research-based CV health promotion program testing differential effects of a population (public health) strategy versus a high-risk approach within four elementary schools. The major goal of "Heart Smart" is to reduce CV risk factors in children with an intervention to facilitate the adoption of healthful lifestyles. Objectives, intervention modalities, and design and evaluation procedures for children and adults in a total school environment (K-6) are described.