Changes in Metabolic and Inflammatory Markers after a Combined Exercise Program in Workers: A Randomized Controlled Trial

ABSTRACT Purpose We investigated the effects of a 16-wk combined exercise training on body composition, and metabolic and inflammatory markers in sedentary middle-aged workers. We also assessed whether alterations in metabolic markers were associated with changes in health-related outcomes. Methods This randomized controlled trial involved 46 participants randomly allocated into control and exercise groups. The exercise group performed 16-wk combined aerobic and resistance training for 75 min per session, 3 times a week. Fasting blood samples were collected at baseline and after 16-wk intervention to determine lipid profile, and metabolic and inflammatory markers as primary outcomes. Results A total of 36 participants completed the intervention (53.70 ± 6.92 yr old; n = 18 in each group). Waist circumference (interaction effect: F = 7.423, P = 0.002), fat mass (interaction effect: F = 5.070, P = 0.011), and muscle mass (interaction effect: F = 5.420, P = 0.007) were improved in the exercise group compared with the control group. Fasting glucose increased after the 16-wk follow-up (time effect: F = 73.253, P < 0.001), without an intergroup difference. Insulin levels were greater in the control compared with exercise group (group effect: F = 6.509, P = 0.015). The control group tended to increase the homeostatic model assessment of insulin resistance index (interaction effect: F = 3.493, P = 0.070) and to decrease the QUICKI index (interaction effect: F = 3.364, P = 0.075) to a greater extent compared with the exercise group. Exercise group reduced leptin (interaction effect: F = 11.175, P = 0.002) and adiponectin (interaction effect: F = 4.437, P = 0.043) concentrations in a greater magnitude than the control group. Interleukin (IL)-6 (time effect: F = 17.767, P < 0.001) and tumor necrosis factor α (time effect: F = 9.781, P = 0.004) concentrations decreased after the intervention, without an intergroup difference. IL-17A levels increased in the control compared with exercise group (interaction effect: F = 5.010, P = 0.033). Effects on adiponectin, IL-6, and IL-17A levels seem to depend on baseline body mass index, age, and sex. Percentage changes in leptin correlated positively with changes in homeostatic model assessment of insulin resistance index in the exercise ( r = 0.565, P = 0.015) and control ( r = 0.670, P = 0.002) groups. Conclusions A combined training program can be an effective strategy to improve body composition and inflammatory markers and prevent marked reductions in insulin sensitivity among middle-aged workers.