¹ School of Medicine, University of Queensland, Brisbane, Australia
² School of Human Movement Studies, University of Queensland, Brisbane, Australia
³ Diamantina Institute, University of Queensland, Brisbane, Australia

Correspondence to:
Professor Thomas H Marwick, University of Queensland School of Medicine, Princess Alexandra Hospital, Brisbane, Q4102, Australia; t.marwick@uq.edu.au

Objective: To identify the effects of a 1-year exercise intervention onmyocardial dysfunction in patients with type 2 diabetes mellitus(T2DM).

Design: Randomised controlled trial, the Diabetes Lifestyle InterventionStudy.

Setting: University hospital.

Patients: 223 T2DM patients without occult coronary artery disease, aged18–75 were randomised to an exercise training group (n= 111) or a usual care group (n = 112). Complete follow-up datawere available in 176 (88 exercise, 88 usual care).

Interventions: Exercise training consisted of gym, followed by telephone-monitoredhome-based exercise training.

Main outcome measures: Tissue Doppler-derived myocardial velocities, strain-rate andstrain, body composition, glycated haemoglobin (HbA_1c), maximumoxygen consumption (VO_2max) and physical activity.

Results: Overall changes in myocardial function were not different betweengroups despite improvements in waist circumference, fat mass,blood glucose, HbA_1c, insulin sensitivity, VO_2max and 6-minutewalk distance in the intervention group (p<0.05). The latteralso spent significantly more time in vigorous activity (p<0.05).A post-hoc analysis revealed that intervention patients whospent more time in both moderate and vigorous activity showeda significant improvement in myocardial tissue velocity (p<0.01),HbA_1c (p = 0.03) and VO_2max (p = 0.03) compared to controls.Myocardial strain rate (p = 0.03) and HbA_1c improved in interventionpatients with the greatest increase in moderate activity (p= 0.03).

Conclusions: In patients with T2DM, current exercise recommendations ledto an improvement in metabolic function, but failed to improvemyocardial function in the overall group. Patients with greaterincreases in both moderate and vigorous activity showed improvementsin myocardial function, glycaemic control and cardiorespiratoryfitness.