Effects of Different Intensities of Aerobic Exercise on Cardiorespiratory Fitness and Levels of Plasma Malondialdehyde and Superoxide Dismutase

Abstract

OBJECTIVES This study aimed to compare the effects of different intensities of aerobic exercise on cardiorespiratory fitness (CRF), plasma malondialdehyde (MDA), and superoxide dismutase (SOD) levels before and after an 8-week exercise.METHODS Twenty-seven male university students were randomly divided into three intensity groups: light intensity (LI; 30-39% HRR), moderate intensity (MI; 40-59% HRR), and vigorous intensity (VI; 60-89% HRR). The study variables measured CRF factors such as maximal/peak oxygen uptake, ventilation, exercise time, and oxidative stress. MDA and SOD levels at rest, and following a graded exercise cessation before and after an 8-week exercise. Statistical analysis conducted two-way ANOVA with repeated measures after testing the normality of variables among groups using the Levene test.RESULTS The results showed significant increases in CRF factors, such as VO2 peak/max, absolute VO2, and exercise time at both moderate and vigorous intensities after 8 weeks. Furthermore, there were significant increases including ventilation at all three intensities after the 8-week exercise. The SOD level showed a significant difference in the low intensity exercise group, but there was no significant difference at the three intensities after exercise. Plasma MDA differed significantly at low and moderate intensities after exercise.CONCLUSIONS Based on these results, this study concluded significant improvements in cardiorespiratory fitness (CRF) factors such as VO2peak/max, absolute VO2, and exercise time in both moderate and vigorous intensities exercise groups after exercise of 8 weeks. There were significant increases at three intensities after exercise of 8 weeks in ventilation. SOD levels also showed an increase in the low-intensity exercise group, while plasma MDA decreased in low and moderate-intensity exercise groups.