High Blood Pressure (HBP) is a major health problem in the United States, with most adults >35 years of age exhibiting BP above optimal levels. Persons with HBP exhibit subclinical vascular disease, which is associated with increased risk for cardiovascular and cerebrovascular morbidity and mortality. Although pharmacologic treatments have proven to be successful in reducing HBP in many patients, drug therapy is not always successful and may be associated with iatrogenic effects that compromise compliance and impair quality of life. Furthermore, abnormalities associated with HBP, including insulin resistance and dyslipidemia, may persist or may even be exacerbated by anti-hypertensive medications. Thus, there continues to be a need to develop behavioral treatments for reducing HBP. There is now good reason to believe that diet and exercise may be one such approach. The study proposed in this application will build upon our previous work in which we demonstrated that exercise, especially when combined with a behavioral weight loss program, resulted in clinically significant BP reductions. In addition, feeding studies have demonstrated that a diet high in low fat dairy products as well as fruits and vegetables (i.e., the DASH diet) may significantly reduce BP without weight loss. The present application seeks to extend these findings by (a) evaluating the efficacy of the DASH diet in a free-living situation; (b) considering the DASH diet alone and in combination with a cognitive-behavioral weight loss program including aerobic exercise; (c) examining the impact of diet and exercise on cardiac, metabolic, and vascular function, and (d) following patients for one year to determine the longer term impact of the interventions on BP, body weight, and cardiovascular function. One hundred twenty men and women with HBP will be randomly assigned to the DASH diet alone, the DASH diet combined with a behavioral weight loss program, or to a usual care control condition. Before and after 4 months of treatment, patients will undergo assessments of BP and measures of arterial stiffness, endothelial function, baroreflex control, body composition, insulin resistance, systemic hemodynamics, and left ventricular structure and function. Twelve month follow-up will assess maintenance of benefit. The data generated from this study will have important clinical significance by determining the extent to which the DASH diet, alone and combined with caloric restriction and exercise, may lower BP and improve associated risk factors.
