Effect of exercise intensity and oxygen consumption on blood lipid peroxidation

Abstract

Background: It is well known that physical exercise is associated with an increase in reactive oxygen species production due to oxygen consumption. However, other factors related to the intensity of exercise could also be important in understanding the oxidative stress related to exercise. Thus, this study aimed to analyze the influence of exercise intensity on plasma lipid peroxidation levels, considering the same total amount of oxygen consumption. Methods: Twelve male trained subjects (aged 20.8 ± 2.6 years) were enrolled in this study. The procedures were divided into three distinct phases at intervals of 96 hours. Firstly, all subjects were submitted to a maximal oxygen capacity test on a cycloergometer to define the exercise intensity for subsequent tests. Then, an exercise protocol consisting of 20 minutes at 55-60% of maximal oxygen uptake and 15 minutes at 75-80% of maximal oxygen uptake was performed on a cycloergometer. Although the intensity and duration of the two exercises were different, the total amount of oxygen consumption was similar. A blood sample for MDA determination was collected before, immediately after, and one hour after each physical test. Results: Plasma MDA concentration increased immediately after both exercise tests and remained high one hour after both exercise protocols. The results showed that plasma MDA concentration was significantly higher in the exercise with higher intensity compared to the lower intensity exercise protocol. Conclusion: Our results suggest that lipid peroxidation induced by acute exercise depends not only on the total amount of oxygen consumed during physical exercise but also on the intensity of the exercise.