Sprint interval training vs. combined aerobic+resistance training in overweight women with type 2 diabetes.

Background Aerobic and resistance training have known efficacy for treating type2 diabetes (T2D). Less is known about interval training in this population. We examined the effects of sprint interval (SIT) and combined aerobic + resistance (COMB) training on HbA1C and (Primary Outcome) in participants with T2D. Secondary outcomes included HOMA-IR and standard clinical chemistries. Exploratory/Tertiary included immerging cardiovascular disease risk indices. Methods Participants (N=52; 45-60y, BMI>30kg/m2, HbA1c, ≥6.5%) were randomly assigned to either SIT (n=17), COMB (n=17) or usual care control (Control, n=18) for 10-weeks. Data were analyzed by ANOVA and effect sizes estimated using Cohen's D (CD). Results We observed significant reductions in HbA1c for SIT (-1.82%, 95% CI, -2.50, -1.14) and COMB (-1.24%, 95% CI, -2.19, -0.29), but not Control (0.02%, 95% CI, -0.67, 0.71). Secondary outcome analysis demonstrated significant reductions in HOMA-IR for SIT (-4.89, 95% CI, -6.94, - 2.83) and COMB training (-2.90, 95% CI, -5.00, -0.79), but not Control (-0.44, 95% CI, -3.44, 2.46). Effect size estimates and accompanying confidence interval bound were deemed "large" for HBA1c and moderate-to-large for HOMA-IR. Non-significant changes for the Control group were deemed "trivial." Both analyses were significant vs. Control. Similar patterns were observed for most standard laboratory measures and tertiary outcomes. Conclusions Our results demonstrate that SIT and COMBO training are effective exercise training regimens in overweight women with T2D independently of changes in body mass.