Introduction & Aims: Arterial stiffness (AS) is thought to increase with glucose intolerance. Combined aerobic and resistance moderate intensity continuous training (C-MICT) has been shown to improve AS in people with chronic disease. The combination of high-intensity interval aerobic with high-intensity resistance training (C-HIIT) has not been previously investigated in adults with type 2 diabetes (T2D). We aimed to compare the efficacy of 8 weeks of low volume C-HIIT and C-MICT on AS, central and peripheral blood pressures in adults with T2D.
Methods: Forty sedentary adults (60±8y) with overweight/obesity (BMI=31.5±6.9kg/m2) and T2D (glycated haemoglobin [HbA1c] 61±13 mmol/mol [7.7±1.2%]) were randomised into 8wks of either: low volume C-HIIT (n=14), C-MICT (n=16), or control (n=10). C-HIIT involved aerobic exercise for 4min at 85-95% peak heart rate (HRpeak) followed by high-intensity resistance training (Rate of Perceived Exertion [RPE] ≥17) involving 8 exercises for 1-min each, on three days/week. Session time was 26mins = 78mins/week. C-MICT comprised aerobic exercise for 150mins/wk over four days at 55-69% HRpeak and moderate intensity resistance training 60mins/wk (RPE 11-13). Total exercise time = 210 mins/week. AS was assessed using pulse wave velocity (PWV), central blood pressures were assessed using pulse wave analysis and peripheral pressures using sphygmonometry; at baseline and post-intervention. ANCOVA was used to determine differences in change scores between groups using the baseline value as the covariate.
Results: There were no significant between-group differences for change in PWV (0.2±0.1m/s, 0.2±0.2m/s, and 0.2±0.4m/s for C-HIIT, C-MICT and control, respectively), central systolic (0.2±2.7mmHg, -1.3±1.3mmHg, 2.8±3.7mmHg) and diastolic (-0.6±1.5mmHg, -1.8±1.1mmHg, 1.7±3.2mmHg) pressures, and peripheral systolic (0.2±3.1mmHg, -1.2±1.5mmHg, 3.4±4.0mmHg) and diastolic (-0.4±1.5mmHg, -1.7±1.1mmHg, 1.7±3.1mmHg) pressures.
Conclusion: The novel findings from this study are that 8 weeks of low volume C-HIIT and C-MICT did not significantly reduce AS, central or peripheral blood pressures in adults with T2D.
Trial Registration: ACTRN12615000475549.