Journal of Preventive Medicine

Introduction
Obesity as a chronic disease is caused by abnormal or excessive accumulation of fat, which can harm health. Since obesity is associated with an increased risk of atherosclerosis, diabetes, metabolic syndrome, non-alcoholic fatty liver disease, cancer, heart disease and reduced life expectancy, new strategies to minimize the negative effect of obesity on the quality of life (QoL) and health care systems should be developed. Obesity, especially central obesity, is also related to many endocrine disorders such as thyroid dysfunction. Recent studies have shown that BMI higher than normal level is associated with increased risk of thyroid cancer. A higher serum level of TSH can cause thyroid malignancies in obese people. Obese people have higher LDL, total cholesterol and triglyceride level. Fat accumulation in arteries cause the blockage of arteries and, thus, the narrowing of the walls of arteries, resulting in high blood pressure. In addition, the accumulation of fat inside non-fat cells causes cell dysfunction or death.
Endurance training and resistance training in obese people can have beneficial effects on cardiovascular risk factors, but it seems that concurrent endurance and resistance training is more effective It has been recommended that patients perform 3-5 sessions of endurance training and 2 sessions of resistance training per week, which can be time-consuming. As a result, by performing concurrent training for 3 sessions a week, they can benefit from the endurance and resistance exercises by spending the least amount of time. Since the prevalence of obesity in women is higher than in men and this issue can cause the society to face many problems, finding a suitable solution to reduce obesity, which itself is the cause of many diseases, is of great importance. This study aims to investigate the effect of concurrent endurance-resistance training on TSH, lipid profile, and physical function indicators in overweight and obese women.

Methods
This is a quasi-experimental study. The study population consists of overweight and obese women referred to the health centers in Neyshabur, Iran. After obtaining informed consent from participants, recording their demographic information, blood sampling, and physical function tests in the pre-test phase, the participants were divided into two training (n=15) and control (n=15) groups randomly by lottery method. Then, the participants in the training group performed concurrent endurance-resistance training for 8 weeks, while the control group did not perform any exercises during this period. Each training session lasted approximately 60-90 minutes. First, the participants performed warm-up movements for 10 minutes. Then, they performed resistance exercises followed by endurance exercises. After finishing the main exercises, they performed movements to cool down for 10 minutes. Resistance exercises included movements with elastic bands or with the help of wall. Endurance exercises included running and jumping rope. The intensity of running was controlled through calculating the wrist pulse rate by subtracting the age from 220, and intensity of jumping rope was controlled by counting the number of jumps per minute. After the end of the intervention, the post-test assessments were conducted. Statistical analysis was in SPSS software, version 23 and the significance level was set at 0.05.

Results
The results of repeated measures analysis of variance showed that concurrent training caused a significant reduction in BMI (P=0.03, partial eta squared [pη2]=0.66). However, there was no significant change in body weight, WHR, and body fat percentage (P=0.21). The changes in daily calorie consumption were not significantly different between the two groups (P=0.13). Moreover, concurrent training significantly improved endurance, upper and lower body muscle strength, and HDL (P<0.001, pη2=0.32-0.75). No significant changes were observed in the levels of TSH, LDL, triglycerides, and total cholesterol (P=0.70-0.90).

Conclusion
Regarding the effect of 8 weeks of concurrent endurance-resistance training in overweight and obese women on the variables related to body composition, a significant reduction was observed in the BMI, but no significant difference was observed in body weight, body fat percentage, and WHR between the two groups. A significant increase in the physical function variables was also observed. Moreover, there was a significant increase in HDL level, but the changes in LDL, triglyceride and total cholesterol were not significant. After 8 weeks of concurrent training, no significant difference was observed in the TSH level between the two groups. According to the results, trainers and healthcare providers for women in Iran can use concurrent endurance-resistance training to improve physical function indicators and some cardiovascular risk factors in obese and overweight women. More research is needed to find a suitable exercise program with sufficient intensity and duration to affect other cardiovascular risk factors and TSH level of obese and overweight women.

Ethical Considerations
Compliance with ethical guidelines
This study was approved by the Ethical Committee of Hakim Sabzevari University, Sabzevar, Iran (Code: IR.HSU.REC.1397.012).

Funding
This research did not receive any grant from funding agencies in the public, commercial, or non-profit sectors.

Authors' contributions
Methodology: Amir Hossein Haghighi, and Roya Askari; Investigation: Amir Hossein Haghighi, and Fateme Shahri; Statistical analysis: Fateme Shahri and Hadi Shahrabadi; Writing the original draft: Fateme Shahri; Review and editing: Amir Hossein Haghighi, and Hadi Shahrabadi; Supervision: Amir Hossein Haghighi.

Conflicts of interest
The authors declared no conflict of interest.


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