The Effect of Different Intensity Exercise on Energy Consumption and Metabolism Substrate in Obese Adult Women

Abstract Background This study aims to compare differences between obese and normal-weight females in maximal fat oxidation (MFO) and exercise intensity eliciting MFO (Fat max ), as well as explore the relationship between cardiopulmonary function and Fat max . Methods Nine obese female (O Group) and nine subjects with normal weight (C Group) participated in this research. Each individual tested by using a MetaMax 3B metabolimeter was performing an incremental graded exercise protocol on an electronic bicycle ergometer to evaluate maximal oxygen uptake (VO 2max ). And, after, exercises at 25%, 35%, 45%, 55%, 65% and 75% of VO 2max were conducted on a separate day to assess MFO and Fat max . Results The results showed that, in exercises of the same intensity (%VO 2max ), VO 2 /kg and MET were significantly lower in O Group than these in C Group, while EE/kg was significantly lower. Moreover, the O group had lower VO 2max /kg (P < 0.01 ), AT-VO 2 /kg ( P < 0.05 ), and Fat max -VO 2 /kg ( P < 0.05 ), the obese women reached MFO (0.22-0.44g/min) at 44.67–59.40% of VO 2max more than C group. Conclusions In conclusion, the application of the graded exercise protocol during this study can get accuracy on MFO and Fat max estimation, and ensure that the use of Fat max can be applied to improve cardiorespiratory fitness.