Exercise as a Tool for Studying the Mechanisms and Applicability of Glycemic Variability (ETSMAGV)

The aim this study is characterize glycemic variability using linear and nonlinear mathematical tools, under basal conditions and in response to specific protocols acute exercise that evoke oxidative stress and inflammation in healthy subjects and type 2 diabetes patients. For this purpose, the sample size will consist of 37 individuals healthy and 32 without type 2 diabetes mellitus, which will undertake the two types of exercise, randomly distributed. The maximal incremental exercise test will be performed in electrically braked cycle ergometer (ER-900, Jaeger, Wu¨ rzburg, Germany) in order to assess possible contraindications to the proposed protocol as well functional capacity, which will be used in prescription of the aerobic exercise session and a testing strength maximal will be conducted and used in the prescription of the eccentric exercise session.

The glucose variability will be assessed by continuous glucose monitoring system (CGMS) during 72h. Glucose variability will be evaluated by glucose standard deviation, glucose variance, mean amplitude of glycemic excursions (MAGE), and glucose coefficient of variation (conventional methods) as well as by spectral and symbolic analysis (non-conventional methods). Physiological mechanisms altered by exercise protocols will be measured in blood samples., Human Soluble Interleukin-6 ( HU IL 6 ELISA KIT - BIOSOURCE) and Glutathione (GSH) indicator of oxidative stress (GSH assay in: Rahman I, Kode A, Biswas SK. Nat Protoc. 2006;1(6):3159-65). The aerobic session will consist of 40 min of lower limb bicycle at 70% of the peak heart rate, as determined in the incremental exercise test and eccentric session will consist of 40 min of one lower -limb exercises (leg press) with 6 sets of 10 repetitions at 120% of 1-RM. The protocol was approved by the Ethics in Research Committee at Hospital de Clínicas de Porto Alegre and all patients will provide their written informed consent before the participation.The research will be performed at the Exercise Pathophysiology Research laboratory of the Hospital de Clínicas de Porto Alegre. We believe that signs of glycemic variability has characteristics detectable by alternative, related to hysiological processes such as oxidative stress and inflammation, evoked by aerobic and eccentric exercise protocols mathematical methods, may help explain the acute response of healthy individuals and patients with type 2 diabetes.