- Participants will be non-smoking, healthy, men and women with no known cardiovascular or metabolic diseases as assessed by a medical history and approval by their physicians to participate. All participants will be active (>30 min, 4d/wk of structured physical activity) as assessed by a Physical Activity questionnaire, normal weight (BMI=20-27.5 kg/m2; % body fat<30%), middle aged (25-55 years), and weight stable (+/-2kg) for at least 6 months prior to beginning the study