BACKGROUND:

Approximately 50 million Americans suffer from hypertension, a condition associated with increased risk for stroke, heart attack, and kidney failure. While non-pharmacological intervention has resulted in dramatic reductions in resting systolic and diastolic blood pressure for those with elevated pressures, a debate continues over the efficacy of pharmacological intervention because of deleterious side effects. As a result, there has been an increased interest in aerobic exercise as a non-pharmacologic approach in treating hypertension. Recent reviews of literature have synthesized research using the 'traditional' approach (chronologically arranging and describing the studies, perhaps by sub-topic) which may result in subjective, non-replicable conclusions. Consequently, the relationships among such variables as subject characteristics, experimental design quality, training program characteristics, and how they contribute to changes in resting systolic and diastolic blood pressure is not clear.

The meta-analytic approach is used in the study to synthesize research on the relationships among variables associated with aerobic exercise intervention and resting systolic and diastolic blood pressure in adults. Meta-analysis is a method of pooling the results of separate studies. It is a quantitative approach for increasing statistical power of primary end points and subgroups, resolving uncertainty when studies disagree, improving estimates of effect sizes, and answering questions not posed at the start of individual trials.

DESIGN NARRATIVE:

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.