Effects of Different Intensities of Endurance Exercise on Oxidative Stress and Leukocyte Activation Markers

Abstract

Acute endurance exercise increases oxygen consumption in many organs and generates reactive oxygen species (ROS). Numerous studies have investigated the effects of different exercise intensities on markers of ROS and leukocyte activation, but little work has been done on estimating changes of enzymatic and non-enzymatic antioxidant capacity for ROS generated with different exercise intensities. PURPOSE: The purpose of this study was to investigate the effects of three different intensities of exercise based on anaerobic threshold (AT) on oxidative stress and leukocyte activation markers. METHODS: Eight healthy male subjects performed three different intensities of exercise for 20 min: (1) 70% AT (low-intensity: LI), (2) 100% AT (moderate-intensity: MI), and (3) 130% AT (high-intensity: HI) on bicycle ergometers. A control (C) trial was conducted under resting condition. Blood samples were taken at pre-exercise, immediately after exercise and 30 min after exercise. The changes in derivatives of reactive oxygen metabolites (d-ROMs), leukocyte activation markers (MPO and calprotectin), total antioxidant capacity (TEAC), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) were measured. RESULTS: Plasma d-ROMs values were significantly higher than pre-exercise values immediately (P<0.01) and 30 min after exercise (P<0.05) only in the HI trial. Plasma MPO values did not change significantly in any trials, but percent changes in MPO from pre-exercise to post-exercise were higher following the HI trial than the C and MI trials (P<0.01). Plasma TEAC values were significantly increased immediately after exercise in the HI trial (P<0.01). Plasma GPX activity was significantly higher than pre-exercise values immediately and 30 min after exercise in the HI trial (P<0.01), and it was also significantly higher immediately after exercise in the MI trial (P<0.05). Plasma calprotectin, SOD and CAT activities did not change significantly in any trials. CONCLUSIONS:These findings suggest that high-intensity endurance exercise above the AT level increases ROS production through neutrophil activation, but the endogenous enzymatic (especially GPX activity) or non-enzymatic antioxidant capacity would cope with the exercise-induced ROS generation.