The anti-inflammatory effects of exercise training in patients with type 2 diabetes mellitus

BACKGROUND: Diabetes mellitus (DM) and chronic inflammation are strongly related to increased cardiovascular risk. The purpose of this study was to evaluate whether an aerobic training programme would ameliorate inflammatory and anti-inflammatory markers in patients with type 2 DM. DESIGN: Interventional study. METHODS: A total of 60 overweight individuals with type 2 DM, but without vascular complications, were randomly assigned to either a 6-month aerobic exercise training programme (four times/week, 45-60 min/session), designated as exercise group, or to the control group. All participants were on an oral antidiabetic regimen and none was receiving lipid-lowering medications. Anthropometric parameters, cardiorespiratory fitness, glycaemic and lipid profiles, high sensitivity C-reactive protein (hs CRP), adiponectin, interleukin (IL)-10, IL-18, tumour necrosis factor (TNF)-alpha, insulin, reciprocal index of homoeostasis model assessment (HOMA-IR), body fat and blood pressure (BP) were measured at baseline and at the end of the study. RESULTS: In comparison with baseline and control group, exercise-treated patients improved glucose control, lipid profile, exercise capacity (VO2 peak) and exhibited decreased insulin resistance and systolic BP considerably (P<0.05). Plasma adiponectin, TNF-alpha and body weight changed slightly across treatment (P>0.05), whereas diastolic BP and fat mass tended to decrease (P=0.071 and 0.061, respectively). Exercise training reduced hs CRP (from 0.48+/-0.16 to 0.29+/-0.2 mg/dl; P=0.04) and IL-18 (from 315.19+/-122.76 to 203.77+/-96.02 pg/ml; P=0.02). Moreover, exercise provided anti-inflammatory protection through IL-10 increment (P=0.039) and IL-18/IL-10 ratio downregulation (P=0.014). In multiple regression analysis, alteration in IL-18 was independently correlated with hs CRP and VO2 peak changes (P<0.05). CONCLUSION: Aerobic exercise training without significant weight loss improves metabolic profile and exerts anti-inflammatory effects in patients with type 2 DM.