The influence of the level of the visceral fat on the lipid metabolism in obese women exercising at a load of ventilatory threshold

Abstract

Some previous investigations have discussed whether visceral adipose tissue may decrease as a result of exercise intervention. However, there is no evidence that the lipid metabolism of visceral adipose tissue predominates during aerobic exercise. The purpose of this study was to examine whether there is a difference in lipolysis of intra-abdominal fat and endocrine hormone during prolonged exercise at ventilatory threshold (VT) load intensity. Sixteen healthy obese women, aged 51.8 ± 7.5 years were categorized into two groups according to their intra-abdominal fat area: a visceral fat obesity (VF-Ob) group and a subcutaneous fat obesity (SF-Ob) group. Mean ± SD of body weight and body mass index were 67.2 ± 4.0 kg and 28.1 ± 1.7 kg/m^2 respectively for the VF-Ob group, and 68.2 ± 3.0 kg and 27.3 ± 0.7 kg/m^2, respectively for the SF-Ob group. Each subject perfomed a submaximal cycling exercise test for 60 min at a constant VT level load, which had been previously determined by an incremental protocol exercise. There were no significant differences between the two groups in catecholamines, %fat oxidation, insulin, and glucose at each of the measurement points (0, 30, 60 min). Significant differences were found in free fatty acid and glycerol in the VF-Ob group (two-way repeated ANOVA, P<0.05), but these remained unchanged during the last 30 min of exercise. There was no significant difference in energy expenditure of fat metabolism over exercise between the two groups. These results suggest that visceral adipose tissue seems to be affected more instantly by lipolysis than subcutaneous fat tissue during prolonged exercise. However, both types of fat show approximately equal consumption during exercise. Therefore, more investigations are needed to determine whether there is a specific form of metabolism for visceral fat during exercise.