Background: Metabolic syndrome is associated with chronic low-grade inflammation, a condition thought to play a key role in the pathogenesis of the syndrome. Among a number of proinflammatory cytokines, interleukin-18 (IL-18) seems to be the best marker for inflammation among people with metabolic syndrome. The aim of this study was to examine the effect of aerobic training versus strength training on circulating IL-18 and other proinflammatory markers in people with metabolic syndrome.
Methods: Thirty-one inactive men and women with metabolic syndrome were randomized to either high-intensity aerobic interval training (AIT, n=11), strength training (ST, n=10), or a control group (n=10). Exercise training was carried out three times per week for 12 weeks. Serum insulin, high-sensitivity C-reactive protein (hsCRP), IL-18, IL-6, and tumor necrosis factor-α (TNF-α) were measured before and after the intervention.
Results: Serum IL-18 was reduced by 43% after AIT (P<0.001). Although there was no change in TNF-α from baseline after AIT, the levels were lower compared to the ST (P=0.032) and control groups (P=0.039) after the intervention. Total body fat was reduced after AIT (from 33.9 ± 7.3% to 32.2 ± 7.9%, P<0.001) and ST (from 31.2 ± 3.9% to 29.7 ± 3.4%, P=0.025). There were no changes in serum IL-6, insulin, or hsCRP within or between the groups.
Conclusion: Both ST and AIT reduced fat mass. However, only the latter intervention was associated with a more favorable inflammatory status among people with metabolic syndrome.
Clinical trial registration information: http://clinicaltrials.gov/show/NCT00986024/ .