Clinical outcomes to exercise training in type 1 diabetes: A systematic review and meta-analysis

Aims To establish the relationship between exercise training and clinical outcomes in people with type I diabetes. Methods Studies were identified through a MEDLINE search strategy, Cochrane Controlled Trials Registry, CINAHL, SPORTDiscus and Science Citation Index. The search strategy included a mix of key concepts related to trials of exercise training in people with type 1 diabetes; glycaemic control. Searches were limited to prospective randomized or controlled trials of exercise training in humans with type 1 diabetes lasting 12 weeks or more. Results In exercised adults there were significant improvements in body mass Mean Difference (MD): -2.20 kg, 95% Confidence Interval (CI) -3.79-0.61, p=.007; body mass index (BMI) MD: -0.39 kg/m2, 95% CI -0.75-0.02, p=.04; Peak VO₂ MD: 4.08 ml/kg/min, 95% CI -2.18-5.98, p<.0001; and, low-density lipoprotein cholesterol (LDL) MD: -0.21 mmol/L, 95% CI -0.33-0.08, p=.002. In exercised children there were significant improvements in insulin dose MD: -0.23 IU/kg, 95% CI -0.37-0.09, p=.002; waist circumference MD: -5.40 cm, 95% CI -8.45 to -2.35, p=.0005; LDL MD: -0.31 mmol/L, 95% CI -0.55 to -0.06, p=.02; and, triglycerides MD: -0.21 mmol/L, 95% CI -0.42 to -0.01, p=.04. There were no significant changes in glycosylated haemoglobin (HbA1C%), fasting blood glucose, resting heart rate, resting systolic blood pressure or high density lipoproteins in either group. Conclusions Exercise training improves some markers of type 1 diabetes severity; particularly body mass, BMI, Peak VO₂ and LDL in adults and insulin dose, waist circumference, LDL and triglycerides in children.