Exercise Training and Insulin Sensitivity

Regular exercise participation is known to reduce cardiometabolic disease risk but the impact that exercise training has on adipose tissue (AT) metabolism is poorly understood, particularly in humans. It is well established that exercise training improves whole-body glucose levels and increases insulin sensitivity, and this can occur within one or two weeks. These effects are usually due to adaptations in skeletal muscle, the tissue responsible for the majority of glucose disposal. However, many studies have now determined that exercise training also results in adaptations in AT that improve whole-body metabolic health by improving glucose uptake into the AT. Skeletal muscle is thought to account for approximately 75-85% of glucose uptake , and this process is impaired in .individuals who are insulin-resistant state. It is postulated that the increased level of adiposity that accompanies severe obesity would result in higher dependency on AT for glucose uptake as the AT would be a bigger "sink". Thus the role of AT in inducing whole body insulin resistance is still unclear, particularly in individuals with obesity. This study will examine the changes in AT glucose uptake before and after 4 weeks of exercise training in obese individuals and establish if there are sex differences.

All subjects will undergo exercise training for 4 wks. 45-60 min of exercise, 4 sessions/wk supervised, 1 session unsupervised. intensity 60% of VO2 max

All subjects will undergo exercise training for 4 wks. 45-60 min of exercise, 4 sessions/wk supervised, 1 session unsupervised. intensity 60% of VO2 max

Inclusion Criteria: non-smokers, weight stable (<4 kg) within the last 6 months will be recruited for this study. sedentary (not engaged in planned physical activities and performing less than a total of 2 h of physical activity per week during the last 6 months) men and women whose BMI is classified as obese (>30 kg/m2). Exclusion Criteria: cardiovascular disease, uncontrolled hypertension (no beta blockers), smokers, pregnant, have any recent changes in hormonal birth control, or on any medications known to impact metabolism. All participants will be regular sleepers with a duration of 7-9 hours/night. Subjects with orthopedic limitations will not be included.