Exercise training-induced visceral fat loss in obese women: The role of training intensity and modality

Abstract

Visceral fat loss in response to four-cycle ergometer training regimens with explicit differences in exercise intensity and modality was compared. Fifty-nine obese young women (body fat percentage ≥ 30%) were randomized to a 12-week intervention consisting of either all-out sprint interval training (SIT_all-out , n = 11); supramaximal SIT (SIT₁₂₀ , 120% $\dot{V}$ O_2peak , n = 12); high-intensity interval training (HIIT₉₀ , 90% $\dot{V}$ O_2peak , n = 12), moderate-intensity continuous training (MICT, 60% $\dot{V}$ O_2peak , n = 11), or no training (CON, n = 13). The total work done per training session in SIT₁₂₀ , HIIT₉₀ , and MICT was confined to 200 kJ, while it was deliberately lower in SIT_all-out . The abdominal visceral fat area (AVFA) was measured through computed tomography scans. The whole-body and regional fat mass were assessed through dual-energy X-ray absorptiometry. Pre-, post-, and 3-hour post-exercise serum growth hormone (GH), and epinephrine (EPI) were measured during selected training sessions. Following the intervention, similar reductions in whole-body and regional fat mass were found in all intervention groups, while the reductions in AVFA resulting from SIT_all-out , SIT₁₂₀ , and HIIT₉₀ (>15 cm² ) were greater in comparison with MICT (<3.5 cm² , P < .05). The AVFA reductions among the SITs and HIIT groups were similar, and it was concomitant with the similar exercise-induced releases of serum GH and EPI. CON variables were unchanged. These findings suggest that visceral fat loss induced by interval training at or above 90% $\dot{V}$ O_2peak appeared unresponsive to the change in training intensity. Nonetheless, SIT_all-out is still the most time-efficient strategy among the four exercise-training regimes for controlling visceral obesity.

Keywords: abdominal fat; continuous training; interval training; lipolytic hormones; obesity.