Additional exclusions are: 1) exercise limiting neuromuscular, joint/bone, cardiovascular, peripheral vascular, cerebrovascular or pulmonary disease; 2) abnormal treadmill stress test or contraindication to testing (recent MI, CHF, pulmonary embolus, significant aortic stenosis); 3) uncontrolled hypertension; 4) unstable diabetes or other endocrinopathy; 5) active liver disease (>3X normal LFTs); 6) major psychiatric illness that would affect the ability to understand and cooperate fully with the study protocol; 7) massive obesity (BMI>40); anemia; 8) consistent use of alcohol (>2 drinks/d); 9) involvement in an ongoing exercise program (>2Xwk for 20 min at an intensity that could produce sweating) in the last 6 months.