Document Type : Original Article

Authors

• Behnam Bagherzadeh Rahmani ¹
• Amir Hossein Haghighi ²
• Roya Askari ³

¹ PhD Student in Exercise Physiology, Faculty of Sport Sciences, Hakim Sabzevari University, Sabzevar, Iran.

² Professor at Department of Exercise Physiology, Faculty of Sport Sciences, Hakim Sabzevari University, Sabzevar, Iran.

³ Associate Professor at Department of Exercise Physiology, Faculty of Sport Sciences, Hakim Sabzevari University, Sabzevar, Iran

Abstract

Extended Abstract
Background and Aim: In recent decades, the prevalence of obesity and cardiovascular diseases has increased, contributing to metabolic disorders and chronic inflammation (1, 3, 4). Interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) play key roles in inflammation and insulin resistance (5, 8, 9, 11). While IL-6 exhibits anti-inflammatory effects in response to exercise, its secretion from adipose tissue can exacerbate chronic inflammation (6-9). Physical training, particularly a combination of resistance and aerobic training, has been shown to reduce inflammation, improve body composition, and enhancing physical fitness (14, 18). The physiological adaptations induced by resistance training depend on how it is performed (14, 17). This study aimed to examine the effects of traditional and circuit resistance training combined with aerobic exercise on pro-inflammatory adipokines (IL-6 and TNF-α), body weight, and muscle strength in obese men. 
Materials and Methods: This quasi-experimental study employed a pre-test and post-test design over 12 weeks, involving 36 obese men. Participants were recruited through public advertisements and randomly assigned to three groups: control, traditional resistance training + aerobic training (TRT+AT), and circuit resistance training + aerobic training (CRT+AT). Inclusion criteria included an age range of 20–32 years, a BMI over 30 kg/m2, no regular physical activity in the past six months, and general health. Exclusion criteria criteria encompassed the use of metabolism-affecting drugs, joint disorders, and chronic diseases. The study was approved by the Hakim Sabzevari University Ethics Committee (code: IR.HSU.REC.1401.004). All participants were informed about the study protocol and provided written consent. The training program included a 10-minute warm-up, resistance training, and a 5-minute cool-down. Resistance training consisted of eight exercises (four upper-body and four lower-body movements) with progressive intensity increments: 55% 1RM (weeks 1–4), 64% 1RM (weeks 5–8), and 75% 1RM (weeks 9–12) (20). TRT was performed in three sets, while CRT was executed in a circuit format. Aerobic training was performed on a treadmill after a 5-minute rest at an intensity of 45–65% Heart rate reserve, adjusted using the Karvonen formula (21, 22). The control group maintained their usual lifestyle without any exercise interventions. Body weight was measured using a calibrated scale, Upper-body and lower-body strength were evaluated via bench press and leg press, respectively. Blood samples were collected 48 hours before and after the intervention following 12 hours of fasting. Plasma IL-6 and TNF-α levels were measured using the ELISA method. The Shapiro-Wilk test was used to assess data normality. Repeated-measures ANOVA was employed for between-group comparisons, while sheffe test was used for within-group analyses. Statistical analyses was performed using SPSS version 29, with a significance level set at p<0.05.
Findings: The Shapiro-Wilk test confirmed the normal distribution of data (p>0.05). Between-group comparisons revealed significant changes in IL-6 and TNF-α levels (p<0.001). Post-hoc analysis showed a significant decrease in IL-6 levels in both the TRT (p<0.001) and CRT (p<0.001) groups compared to the control, with no significant difference between the two training groups (p=0.18). Similarly, TNF-α levels decreased in the TRT (p=0.02) and CRT (p=0.01) groups compared to the control, with no significant difference between the two training groups (p=0.15). The control group showed no significant changes in IL-6 (p=0.38) or TNF-α (p=0.58). Muscle strength assessments showed significant improvements in both TRT and CRT groups for bench press and leg press (p<0.001), with no significant difference between the two groups (p=0.21 for bench press, p=0.24 for leg press). The control group showed no significant changes in bench press (p=0.15) or leg press (p=0.66). Body weight also showed significant changes (p=0.01). The CRT group had a significant reduction in weight compared to the control (p=0.02), while the difference between the TRT and control groups was not statistically significant (p=0.07). Within-group analysis revealed a significant weight reduction in both training groups (p<0.001), while the control group experienced a significant weight gain (p<0.001). Overall, both TRT and CRT effectively reduced IL-6 and TNF-α levels, increased muscle strength, and promoted weight loss, with no significant differences between the two training methods.
Conclusion: This study demonstrated that 12 weeks of traditional and circuit resistance training combined with aerobic exercise significantly reduced IL-6 and TNF-α levels, decreased body weight, and increased muscle strength in obese men. CRT had a greater impact on weight reduction, which may be due to shorter rest periods and higher post-exercise metabolic rate (27, 34). Consistent with previous research, our findings suggest that combining resistance and aerobic training elicits greater anti-inflammatory effects than either modality alone (25, 26). Training intensity and duration appear to be key factors influencing IL-6 and TNF-α reduction (27, 29, 31).
Since reducing fat mass and modulating inflammatory adipokines are critical for preventing metabolic complications of obesity, well-structured exercise programs can play a significant role in improving physical health, reducing economic burdens, and lowering obesity- and diabetes-related mortality rates.
Ethical Considerations
This study was approved by the Ethics Committee of Hakim Sabzevari University (IR.HSU.REC.1401.004). All participants were informed about the study procedures and provided written informed consent.
Compliance with Ethical Guidelines
The research followed the ethical standards of the Declaration of Helsinki and institutional guidelines. Participation was voluntary, and confidentiality was maintained.
Funding
This study received no external funding and was conducted with the resources available to the research team.
Conflicts of Interest
The authors declare no conflicts of interest regarding the publication of this study.

Keywords

• Obesity
• Inflammation
• Interleukin-6
• Tumor necrosis factor alpha
• Exercise training