Determinants of the Changes in Glycemic Control with Exercise Training in Type 2 Diabetes: A Randomized Trial

AIMS: To assess the determinants of exercise training-induced improvements in glucose control (HbA(1C)) including changes in serum total adiponectin and FFA concentrations, and skeletal muscle peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) protein content. METHODS: A sub-cohort (n = 35; 48% men; 74% Caucasian) from the HART-D study undertaking muscle biopsies before and after 9 months of aerobic (AT), resistance (RT), or combination training (ATRT). RESULTS: Changes in HbA(1C) were associated with changes in adiponectin (r = −0.45, P = 0.007). Participants diagnosed with type 2 diabetes for a longer duration had the largest increase in PGC-1α (r = 0.44, P = 0.008). Statistical modeling examining changes in HbA(1C) suggested that male sex (P = 0.05), non-Caucasian ethnicity (P = 0.02), duration of type 2 diabetes (r = 0.40; P<0.002) and changes in FFA (r = 0.36; P<0.004), adiponectin (r = −0.26; P<0.03), and PGC-1α (r = −0.28; P = 0.02) explain ∼65% of the variability in the changes in HbA(1C). CONCLUSIONS: Decreases in HbA(1C) after 9 months of exercise were associated with shorter duration of diabetes, lowering of serum FFA concentrations, increasing serum adiponectin concentrations and increasing skeletal muscle PGC-1α protein expression. TRIAL REGISTRATION: ClinicalTrials.gov NCT00458133