Comparison of serum interleukin-18 and C-reactive protein levels in obese and non-obese young men: effects of exercise training and obesity

Regular exercise training has been postulated as an important strategy to reduce inflammatory markers, but it is still not clear what type of training is most appropriate. The purpose of this study was to compare the effects of nonlinear resistance training (NRT) and aerobic interval training (AIT) on interleukin-18 (IL-18) and C-reactive protein (CRP) in obese young men. An additional aim was to compare the inflammatory markers between the obese and non-obese men to determine the obesity effect.
Thirty-eight obese and young men (age=31.4±5.2 year, body fat%=27.3±1.5) were randomly assigned to NRT (n=14), AIT (n=12) and control (CON, n=12) groups. An age-matched control group of non-obese men were also recruited for baseline comparison. Independent t-test and 2-factor repeated measures analysis of variance (ANOVA) were used for analyzing data.
No significant differences were noted at baseline between obese and non-obese men for IL-18 (P=0.17), CRP (P=0.77) and VO2peak (P=0.24). After training, VO2peak increased in NRT (P=0.03) and AIT (P=0.001) compared to the CON, but in AIT more than in NRT (P=0.02). Compared to the CON, both of training were equally effective at reducing fat mass (P=0.001). However, there were no significantly changes in IL-18 (P = 0.26) and CRP (P=0.15) after training.
Lack of significant differences for IL-18 and CRP between obese and non-obese men might be due to the similar status in age and aerobic fitness. It seems that 2 exercise programs could not make a significant reduction in the concentrations of inflammatory markers.