Metabolic Effects of Aerobic Training and Resistance Training in Type 2 Diabetic Subjects

OBJECTIVE To assess differences between the effects of aerobic and resistance training on HbA1c (primary outcome) and several metabolic risk factors in subjects with type 2 diabetes, and to identify predictors of exercise-induced metabolic improvement. RESEARCH DESIGN AND METHODS Type 2 diabetic patients (n = 40) were randomly assigned to aerobic training or resistance training. Before and after 4 months of intervention, metabolic phenotypes (including HbA1c, glucose clamp–measured insulin sensitivity, and oral glucose tolerance test–assessed β-cell function), body composition by dual-energy X-ray absorptiometry, visceral (VAT) and subcutaneous (SAT) adipose tissue by magnetic resonance imaging, cardiorespiratory fitness, and muscular strength were measured. RESULTS After training, increase in peak oxygen consumption (VO2peak) was greater in the aerobic group (time-by-group interaction P = 0.045), whereas increase in strength was greater in the resistance group (time-by-group interaction P < 0.0001). HbA1c was similarly reduced in both groups (−0.40% [95% CI −0.61 to −0.18] vs. −0.35% [−0.59 to −0.10], respectively). Total and truncal fat, VAT, and SAT were also similarly reduced in both groups, whereas insulin sensitivity and lean limb mass were similarly increased. β-Cell function showed no significant changes. In multivariate analyses, improvement in HbA1c after training was independently predicted by baseline HbA1c and by changes in VO2peak and truncal fat. CONCLUSIONS Resistance training, similarly to aerobic training, improves metabolic features and insulin sensitivity and reduces abdominal fat in type 2 diabetic patients. Changes after training in VO2peak and truncal fat may be primary determinants of exercise-induced metabolic improvement.