Author(s): LOPES, W., SIMÕES, C.F., RECK, H.B., LOCATELLI, J.C., DE OLIVEIRA, G.H., OKAWA, R.T.P., O’DRISCOLL, J.M., MOTA, J., Institution: STATE UNIVERSITY OF MARINGA, Country: BRAZIL, Abstract-ID: 524

INTRODUCTION:
High intensity interval training (HIIT) has been shown to improve body composition, inflammatory state and vascular function in individuals with obesity. However, the effects of HIIT on myocardial work (MW) indices remain unclear. Therefore, the aim of this study was to investigate the effects of HIIT on MW in young women with obesity.
METHODS:
Twenty-five young women with obesity (class I and II) were randomized to eight weeks of HIIT or moderate-intensity continuous training (MICT). The HIIT protocol consisted of four 4-minute bouts of walking/running at 85-95% of HRmax, interspersed with 3 minutes of active recovery at 65-75% of HRmax. The MICT protocol consisted of 41 minutes of continuous walking/running at 65-75% of HRmax. Body composition, cardiorespiratory fitness and MW indices (GWI: global work index; GCW: global constructive work; GWW: global wasted work; GWE: global work efficiency) were evaluated before and after the interventions.
RESULTS:
No significant group × time interactions were observed for MW indices. A significant within-group effect of time was observed in the HIIT group, with a reduction in GWW (Δ= −15.23±41.49 mmHg·%, p= 0.042) and an increase in GWE (Δ= 2.39±2.43%, p= 0.005). In contrast, no significant time effects were detected in the MICT group for GWW (Δ= 4.85±62.28 mmHg·%, p = 0.283) or GWE (Δ = 1.21 ± 2.75%, p = 0.101). No significant time effects were observed in GWI (HIIT: p= 0.854; MICT: p= 0.292) or GCW (HIIT: p= 0.646; MICT: p= 0.396), in either group. Both training protocols reduced body fat, however, only HIIT significantly improved cardiorespiratory fitness.
CONCLUSION:
HIIT improved GWW and GWE in young women with obesity, suggesting that this aerobic training modality may contribute to enhanced myocardial efficiency in this population.