Background: Due to the wide range of mechanisms of action of hormonal mediators and other metabolites on the immune system and the function of other tissues of the body, the answers are often different. This is especially true of the response of inflammatory and anti-inflammatory cytokines to exercise in healthy obese or sick individuals. It is well established that obesity or increased body fat levels predispose to most chronic diseases such as type 2 diabetes, respiratory disease, cardiovascular disease or other chronic diseases (1). Among these, IL-1ß is a proinflammatory cytokine that plays an important role in the association of inflammation. However, their exact functional mechanisms under natural conditions as well as in the presence of disease have not yet been fully elucidated (5). IL-1ß is known to regulate the body's inflammatory responses and plays an important role in the association between obesity and inflammatory diseases such as diabetes, metabolic syndrome, atherosclerosis and chronic heart failure (6). In this regard, IL-1ß is a known cytokine among the proteins that regulate cell physiological responses and due to its inflammatory properties has been introduced to develop insulin resistance and a strong mediator to increase it (7). It has been suggested that IL-1ß levels increase in the presence of obesity (2). As some scientific sources indicate its direct relationship with BMI (8). Therefore, it is always hypothesized that weight loss or body fat percentage due to pharmacological or non-pharmacological stimulants such as exercise leading to lower body fat levels is associated with improved components in the inflammatory profile such as IL-1ß , although in this There are also conflicting findings. As in the study of Baldusi et al. (2009), long-term low-intensity aerobic exercise as well as a combined aerobic-resistance training program led to a decrease in IL-1ß levels in obese and diabetic individuals (9). Some studies in animal species have also supported the reduction of this inflammatory cytokine following exercise (10, 11). Contrary to these findings, in another study, plasma IL-1ß levels did not change significantly following a training program (12). Lack of effect of exercise on IL-1ß levels has been reported by some other studies (13). A review of the evidence indicates a mismatch of findings regarding the response or compatibility of IL-10 or other inflammatory components to exercise. On the other hand, due to limited studies in this field on sedentary obese women, the present study aims to determine the effect of a course of aerobic exercise on serum IL-1B levels by emphasizing the pattern of weight changes and other anthropometric indices in middle-aged obese women. Methods: The present study was conducted by quasi-experimental research method and experimental research design with pre-test and post-test design with a control group. The statistical population consists of obese women (36% BMI ≥ 30) in the 21st district of Tehran in the age range of 30 to 40 years (IR. SSRC. REC. 1397. 322). After getting acquainted with the objectives of the study, 30 obese women with inclusion criteria from the statistical population voluntarily participated in the study and were divided into two groups of exercise (6 weeks of aerobic exercise, n = 15) and control (without exercise, n = 15) were divided. Aerobic training and blood sampling: After anthropometric measurements, subjects were asked to come to the blood laboratory for sampling after 10 to 12 hours of night fasting (fasting) between 8 and 9 am. Subjects were asked to refrain from any strenuous physical activity for 48 hours before blood sampling. Blood samples (5 ml) were taken from the left hand vein of each subject in a sitting and resting position and after separating the serum at a temperature of minus 80 until IL-1B was measured (pre-test). Then, the exercise group participated in a 6-week aerobic exercise session with 3 sessions per week in the range of intensity of 60 to 75% of the maximum heart rate in an indoor gym without a slope. Each training session was performed with 5 to 10 minutes of warm-up and stretching movements, then the main stage of the activity was done in the form of running on a flat surface in the indoor space and at the end of cooling for 5 minutes. The intensity of training in each training session was controlled and recorded by a polar pacemaker based on the percentage of maximum heart rate. The main program of each training session was in the form of running at defined intensities, so that the subjects spent the first two weeks with an intensity of 60 to 65, the third and fourth weeks with an intensity of 65 to 75, and the fifth and sixth weeks with an intensity of 70 75% did the maximum heart rate. The volume of activity during the training period started from 10 minutes in the first week and ended to 40 minutes in the last week. Finally, 48 hours after the last training session, blood sampling was performed in the same conditions as the pre-test (post-test). The comparisons between the measurements were determined by paired and unpaired samples t test at P-value of < 0. 05. Results: Findings related to intra-group changes in anthropometric indices in each of the experimental and control groups showed that 6 weeks of aerobic training leads to a significant reduction in anthropometric indices in the experimental group (p <0. 05), but these indices In the control group at the end of the study (post-test) compared to the beginning of the study (pre-test) did not change significantly (p <0. 05). Comparison of baseline levels of serum IL-1B between the experimental and control groups showed that there was no significant difference in this variable between the two groups (p = 0. 683). Could not (p = 0. 219). In other words, aerobic intervention, although it led to a decrease in IL-1B levels in the experimental group, but this change was not statistically significant (Table 2, Figure 4). Serum IL-1B levels also did not change significantly in the control group (p = 0. 718). Conclusion: The findings of the present study showed that aerobic intervention was not associated with a significant change in IL-1B in obese women. In other words, applying 6 weeks of aerobic exercise to 3 sessions per week in the intensity range of 60 to 75% of maximum heart rate does not lead to a significant change in serum IL-1B levels in obese women who have previously been inactive. . However, some recent studies have supported the improvement of inflammatory cytokines in response to aerobic exercise or other training methods. The lack of significant change in IL-1B in the present study can be attributed to the lack of diet control during the training period because the studied obese women followed their diet pattern during the aerobic intervention period. In a recent study, serum resistin levels did not change significantly after 3 months of aerobic exercise in the absence of diet control in obese men (26). In this regard, the findings of a study revealed that 6 months of lifestyle changes in the form of diet in combination with exercise leads to a significant reduction in CRP in elderly women with metabolic syndrome (16). In another study by Bijeh et al., Exercising with dietary calorie restriction in the form of 27 sessions of aerobic exercise during the holy month of Ramadan led to a reduction in body fat percentage with a significant reduction in IL-1B (27). Decreased IL-1B levels through controlled diet and exercise are associated with improved insulin resistance in healthy or sick individuals (28). Researchers also believe that controlling the diet or providing a proper diet when exercising, especially in healthy or obese people, has a stronger effect on the inflammatory profile than when applied alone (29, 30).، 31). It is also possible that balancing or improving the inflammatory profile in response to exercise programs is limited to their levels in skeletal muscle rather than their systemic levels. For example, in one study, 6 months of exercise in the form of 4 to 6 sets of 10-minute cycles per day resulted in decreased levels of TNF-α , IL-6, and IL-1B in skeletal muscle at nine systemic levels in patients with heart failure (32). The findings of this study reveal that aerobic training intervention in absence to in the absence of control diet is not associated with anti-inflammatory property with emphasis on serum IL-1B in obese females.