A Study of Acute Maximal Workload on Oxidative Stress Response with the Obese

Abstract

[Purpose] The purpose of this study was to identify effects of acute maximal workload on oxidative stress of obesity. This study investigates the differences in expression of oxidative stresses between an obese group and a group with normal health after an acute maximal workload.[Subjects] Eighteen men were randomly assigned to one of two groups: an obese group (n=8), and a normal group (n=8). All members of the acute maximal load that participated in the study were between the ages of 20 and 30 years old. The baseline level of obesity was determined as 25% of the fat and body mass index (BMI) 25. [Methods] The treadmill grade was increased 2% every 1 minute (Balke protocol) while speed (3.3mph) was kept constant. The speed was individualized so that exhaustion occurred in approximately 8—12 minutes. Standard criteria for an acceptable VO₂max test included a leveling off of VO₂ with increasing workload, a respiratory exchange ratio (RER) above 1.15 and a peak HR similar to age-predicted maximal values. Both groups stopped eating, smoking, drinking and exercising 21 hours before the test concerning circadian rhythm. After 50 minutes, 10 ml of blood was collected at three different times at rest, at exhaustion, and after 30 minutes of recovery. [Results] There was no significant difference in malondialdehyde assay (MDA) which is a common test for evaluation of lid peroxidation between the normally healthy group and the obesity group after exhaustion and 30 minutes of recovery. [Conclusion] The reason why acute maximal load did not have a significant effect on the MDA activation which is an indicator of lipid peroxidation is that acute maximal load raised the free radical level and the lipid peroxide level; and had a defense mechanism against the generation of free radicals; thus restrained lipid peroxides from being generated by free radicals; consequently they could not have any effect on antioxidation capability.