 In patients with HF-PSF, the investigators will relate dietary changes to biochemical and cardiovascular functional measures. The investigators will study subjects on ad-lib diet and and following three weeks of rigorous dietary modification with the Dietary Approaches to Stop Hypertension DASHsodium-restricted diet SRD. This diet is richer in natural antioxidants and lower in sodium than the usual American diet. The DASHSRD is recommended to lower blood pressure in patients with HTN, and is particularly effective in elderly, obese, and salt-sensitive hypertensives. Dietary sodium restriction is recommended for all HF patients including those with HF-PSF. The investigators hypothesize that the DASHSRD will have favorable effects on oxidative stress, ventricular and vascular function, and blood pressure control in patients with hypertensive HF-PSF. 