The Effect of Exercise Intensity on Serum Leptin and C-Reactive Protein Levels

Recently, serum leptin and C-reactive protein (CRP) levels have been regarded as independent predictive factors for heart disease. Although exercise intensity and duration may influence leptin and CRP concentrations, few studies have investigated this. In addition, leptin and CRP exhibit trends (downward and upward, respectively) after an acute bout of aerobic exercise. There seems to be a negative association between them, which may differ from the baseline; however, no study has tested this assumption. Therefore, we investigated the effect of exercise intensity on serum leptin and CRP levels and compared changes and differences in both relationships with different exercise intensities. In addition to the O2max test, 13 male subjects (21.5 ± 1.8 years old, 18.5 ± 4.0%body fat, 55.0 ± 3.8 mL·kg−1·min−1O2max) exercised at two other exercise intensities (85% O2max and 65% O2max) in a randomized order. Blood samples were collected before and immediately after each trial to analyze pre- and post-exercise leptin and CRP concentrations in the three trials. While there were no significant differences in post-exercise leptin and CRP levels among the different exercise intensities, there were significant differences between leptin and CRP concentrations before and after exercise bouts corresponding to 65% and 85% O2max. In addition, post-exercise leptin and CRP levels were not associated. The results of this study suggest that leptin and CRP do not differ among different exercise intensities. Alteration in CRP and body fat percentage did not contribute to the change in leptin in these acute exercise models.