A016: Effects of HIIT Combined with IET on Cardiac Structure and Functionin Women with NOW

Purpose: The development of a society with increasing unhealthy lifestyles and dietary habits leads to a rise in the population suffering from obesity and cardiovascular disease (CVD). NWO individuals, who are hidden obese individuals, are also at a similar risk. This study aimed to compare the effects of high-intensity interval training (HIIT) and HIIT combined with intermittent energy restriction (IET) on cardiac structure and function and to explore more effective exercise intensities and methods to provide scientific exercise guidance to enhance vascular health and reduce CVD risk factors in NWO women. Method: Forty-five NWO women were randomly divided into a HIIT group, a HIIT combined IET group, and a control group. They completed a maximal oxygen uptake test and an isometric wall squat test to determine exercise intensity. The two-exercise group underwent an 8-week exercise intervention, with three sessions per week. The HIIT group alternated between exercise intensities at 85% and 50% of VO2max, with each intensity lasting for 1 minute, totaling 20 sets with a duration of 40 minutes. The HIIT combined with IET group performed 20 minutes of HIIT followed by 20 minutes of IET. The IET intensity was at 95% of maximal heart rate, each IET set involved 2 minutes of exercise with a 2-minute rest interval in between. Cardiac structure and function were measured before and after intervention and subjected to statistical analysis. Results: After the 8-week exercise intervention of HIIT or HIIT combined with IET, compared to before the intervention, significant improvements in interventricular septal thickness at diastole (IVSd) occurred in the HIIT group (P < 0.01), while the HIIT combined with IET group showed significant improvements in interventricular septal thickness at shrink (IVSs, P < 0.05). Moreover, the changes in IVSd and IVSs before and after the intervention were significantly greater in both exercise groups than in the control group (P < 0.05). The improvement in SV in the HIIT combined with IET group was significantly greater than in the control group (P < 0.05). Conclusion: After an 8-week exercise intervention, HIIT significantly improved IVSd in NWO women, while HIIT combined with IET significantly improved IVSs. Furthermore, the improvement in SV in the HIIT combined with IET group was greater. These results suggest that both HIIT and HIIT combined with IET can improve cardiac structure in NWO women after an 8-week intervention, and HIIT combined with IET is a more effective exercise modality for improving cardiac function.