The long-term goal of this project is to develop and test a nutritional product that will improve physical function in individuals with heart failure (H) in the geriatric population. Our approach to nutritional therapy (NT) focuses on increasing skeletal muscle strength, improving vascular reactivity and optimizing regulation of energy substrate metabolism. All of these anticipated responses to NT should contribute to improved physical performance and thereby interrupt the vicious cycle of heart failure progression that ultimately leads to morbidity and mortality. While the popularity of nutritional supplements designed to address specific health concerns has grown, the credibility of the field has suffered due to an abundance of unsubstantiated claims and unscrupulous sales approaches. Essential Blends LLC is committed to marketing only products that have been developed from sound theory and validated by tightly controlled clinical trials. Thus, our ultimate goal is to perform a tightly controlled clinical trial assessing the response of individuals with HF to NT using our proprietary blend of amino acids. In order to perform such a study, a number of issues must be resolved. It is therefore the goal of this Phase I project to make all the necessary preparations t efficiently perform a controlled clinical trial in the subsequent Phase II aspect of this project. Following are the Specific Aims of this Phase I proposal: Specific Aim 1. To develop a palatable beverage that incorporates all of the essential components in the appropriate amounts in a format that can be produced relatively inexpensively. Specific Aim 2. To perform a pilot study to determine variability in determination of functional capacity in individuals with HF in order to determine the necessary number of subjects for the clinical trial, and to predict power reasonably accurately. Specific Aim 3. To prepare existing data management capabilities for the clinical trial and to expand the subject registry. The outcome of this Phase I project will be completion of all aspects of preparation to perform a clinical trial assessing the benefits of NT with our nutritional formulation.