Inclusion Criteria:  both male and female 50-64 years old no restrictions based on race, ethnicity, or socioeconomic status sedentary individuals (<20 minutes; <3 days/wk. physical activity) post-menopausal women (has experienced 12 consecutive months without menstruation for >5 years).  Exclusion Criteria:  <50 or ≥65 years of age Subjects participating in regular exercise (>20 min/day, >3 days/week) female subjects who are pregnant, lactating or 1 month post-partum currently consuming or had consumed creatine supplementation <1 month prior to screening currently consuming or consumed nitric oxide supplementation <1 month prior to screening currently consuming or had consumed Vitamin C supplementation <2 weeks prior to screening individuals who report chronic infections individuals reporting paralysis due to stroke individuals reporting advanced Parkinson's disease individuals reporting severe rheumatoid arthritis or other serious orthopedic problems that would prevent performance of the exercise tasks individuals currently taking medications that may affect central or peripheral circulation individuals with known cardiovascular and/or metabolic disease current smokers or those who quit <6 months prior to screening individuals with hypercholesterolemia (total cholesterol > 200mg/dL, high density lipoprotein <40 mg/dL, low density lipoprotein >130mg/dL) individuals with hypertension (systolic blood pressure > 150 mmHg and/or diastolic blood pressure >95mmHg). individuals with known kidney disease individuals with known liver disease