 Arm 2: 1. Able to fast overnight or for 6 hours 2. Able to perform light to moderate exercise on an exercise bike 3. Non-diabetic and Body Mass Index 25 4. Age 40 years and 70 years 5. Negative pregnancy test, postmenopausal, or surgically sterilized 6. Negative mammogram at Mayo Clinic within the last 15 months defined as screening mammogram or subsequent diagnostic workup with BI-RADS 1 or 2 final assessment 7. No current breast concerns 8. No history of coronary artery disease, angina, stroke or peripheral arterial disease. 