In the first two years of the study, a meta-analysis was conducted of all studies published since 1966 on aerobic exercise and blood pressure. The study was renewed in FY 2000 to conduct meta-analysis of all studies of exercise training in children and youth under age 21 years in which resting BP was measured. This will include both randomized and non-randomized clinical trials of at least eight weeks duration found in English journals and theses between 1966 and 1999. Standard meta-analysis techniques will be applied.