High Intensity Interval Training and Skeletal Muscle Insulin Sensitivity
A common metabolic disturbance in obesity and obesity-associated disorders is reduced skeletal muscle insulin sensitivity, resulting in compromised glucose homeostasis. Skeletal muscle insulin responsiveness triggers glucose oxidation and non-oxidative glucose disposal (NOGD), which is largely defined as glycogen storage. Whereas exercise training is considered a cornerstone in the prevention and treatment of obesity-related insulin resistance, previous interventions based on a combined endurance and resistance exercise training program revealed a partial restoration of skeletal muscle insulin responsiveness in patients with type 2 diabetes. This partial restoration has been shown to be mainly due to improvements in oxidative glucose disposal, while skeletal muscle NOGD remained unchanged. Thus, we need to identify ways to target NOGD with the hope to restore insulin sensitivity in insulin resistant muscle.
High intensity interval training (HIIT) has classically been applied to augment glycogen levels in training for exercise performance. We hypothesize that HIIT can also be applied stimulate the NOGD, thus restoring skeletal muscle insulin sensitivity in individuals with compromised insulin sensitivity.
HIIT, however, may lead to unfavourable fluctuations in blood glucose levels upon exercise, which may in turn impact the energetic feeling and mood state of these subjects, resulting in a poor long-term adherence to the exercise.
In this study, we will investigate whether a supervised HIIT-based intervention of 12 weeks improves skeletal muscle NOGD capacity in obese pre-diabetics. Furthermore, we will investigate whether the consumption of an insulinogenic, carbohydrate (CHO)-rich drink during and after exercise prevents the adverse effects related to blood glucose fluctuations and promotes the adherence of subjects to the training program on the long term.