Metabolic effects of aerobic training and resistance training in type 2 diabetic subjects: A randomized controlled trial (the RAED2 study)

OBJECTIVE - To assess differences between the effects of aerobic and resistance training on HbA _1c (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 HbA _1c, 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 (VO _2peak) 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). HbA _1c 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 HbA _1c after training was independently predicted by baseline HbA _1c and by changes in VO _2peak 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 VO _2peak and truncal fat may be primary determinants of exercise-induced metabolic improvement.