233-OR: Circulating Inflammatory Biomarkers Are Not Improved with Combined Low-Volume High-Intensity Interval Training and Progressive Resistance Training in Prediabetes

In prediabetes (PD), circulating inflammatory biomarkers are associated with increased CVD¹ risk. Exercise (Ex) has a positive effect on cardiovascular fitness and metabolic outcomes in PD but Ex effects on inflammation markers in PD are not fully known and were investigated in this study. Adults with PD (n=34) and normal fasting glucose (NG) (n=34) were randomised into one of four groups: NG control (NGC, n=16), NG Ex (NGE, n=18), PD control (PC, n=16) and PD Ex (PE, n=18). NGE/PE completed 12 weeks of supervised HIIT and progressive resistance training (PRT) 2 times/week, and NGC/PC unsupervised stretching 3 times/week. Baseline, age and weight were similar in PD and NG. Compared with NG, FPG and HbA1c were higher and VO₂peak was significantly lower in PD (29±7 vs. 33±8 mL/kg/min, p=0.03). Comparing NG and PD at baseline, serum IL-1β was higher in NG (11.4±9.0 vs. 7.9±2.8 pg/mL, p=0.04), IL-12p70 and IL-22 were higher in PD (respectively, 5.7±3.6 vs. 4.4±2.2 pg/mL; 164.6±90.3 vs. 122.2±83.2 pg/mL, both p<0.05) and IL-1α, IL-6, IL-8, IL-15, M-CSF and TNFα were similar. At follow-up, HbA1c was reduced by -0.07±0.11% in NGE and -0.09±0.17% in PC (both p<0.05) and not changed in PE or NGC. PE had an increase in VO₂peak (5.5±7.5mL/kg/min, p=0.01). Inflammatory biomarkers were unchanged in PE but NGE had reduced IL-12p70 (4.3±1.9 to 3.5±0.8 pg/mL, p=0.05) and M-CSF (124.5±58.2 to 93.8±36.2 pg/mL, p=0.02). Analysis of Ex with >80% adherence revealed that IL-1α, IL-1β, IL-8 and IL-15 were reduced in NGE, however no change was seen in PE despite a reduction in HbA1c of -0.14±0.17% (p=0.02). PD is associated with reduced cardiorespiratory fitness and increased IL-12p70 and IL-22. Ex reduced IL-12p70 and M-CSF in those with NG but not PD, even after stratifying by adherence and despite improvements in clinical markers. This study indicates low volume HIIT with PRT may not be adequate to reduce serum inflammatory biomarkers in prediabetes.