Table 1 List of aims and hypothesis for the study

AIM 1: To determine the effects of oral ubiquinol, D-ribose, or a combination of the two administered over 12 weeks on symptoms accompanying low bioenergetics in patients with HFpEF.

 Hypothesis #1: Ubiquinol (600 mg daily), D-ribose (15 g daily), or a combination of the two will enhance the health status of patients with HFpEF as measured by the Kansas City Cardiomyopathy Questionnaire.

 Hypothesis #2: Ubiquinol (600 mg daily), D-ribose (15 g daily), or a combination of the two will increase the level of vigor in patients with HFpEF as measured by the Vigor subscale of the Profile of Mood States.

AIM 2: To determine the effects of oral ubiquinol, D-ribose, or a combination of the two over 12 weeks on biological measures in patients with HFpEF.

 Hypothesis #3: Ubiquinol (600 mg daily), D-ribose (15 g daily), or a combination of the two will improve left ventricular diastolic function measured by advanced echocardiographic imaging in patients with HFpEF.

 Hypothesis #4: Ubiquinol (600 mg daily), D-ribose (15 g daily), or a combination of the two will increase the distance that patients with HFpEF can walk in 6 min.

 Hypothesis #5: Ubiquinol (600 mg daily), D-ribose (15 g daily), or a combination of the two will decrease venous blood B-type natriuretic peptide (BNP) levels in patients with HFpEF.

 Hypothesis #6: Ubiquinol (600 mg daily), D-ribose (15 g daily), or a combination of the two will decrease the lactate/ATP ratio in patients with HFpEF.