نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشجوی دکتری فیزیولوژی ورزشی، دانشکده تربیت بدنی و علوم ورزشی، دانشگاه تبریز، تبریز، ایران.
2 استاد گروه فیزیولوژی ورزشی، دانشکده تربیت بدنی و علوم ورزشی، دانشگاه تبریز، تبریز، ایران.
3 دانشیار گروه فیزیولوژی ورزشی، دانشکده تربیت بدنی و علوم ورزشی، دانشگاه تبریز، تبریز، ایران.
4 استاد گروه فیزیولوژی ورزشی، دانشکده تربیت بدنی و علوم ورزشی، دانشگاه عراق، کربلا، عراق.
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Extended abstract
Background and Aim: High-intensity interval training (HIIT) has been considered as an effective intervention in body composition improvement, insulin sensitivity and cardiovascular health in overweight and obese individuals. It seems that this type of exercise can be used as an effective training strategy for improving anthropometric and metabolic indices in overweight and obese individuals. In addition, previous studies it have confirmed that HIIT is more effective on serum levels and activity of Agouti-related peptide (AgRP) via improving insulin sensitivity, changes in appetite regulator hormones and effect on hypothalamic leptin pathways. Moreover, the AgRP is known as a signaling peptide that can affects nutritional behavior, energy homeostasis, and fat accumulation. Preliminary evidence also indicates that HIIT may increase the serum levels of AgRP, however, some studies have reported a contradictory results as decrease or lack of significant change. Although, some studies suggest that there is a relationship between obesity indices, including body fat percentage and waist to hip ratio, and serum lipids with AgRP, however, this relationship has a complex and nonlinear nature and probably the role of AgRP in lipid metabolism is exerted by indirect pathways such as changes in body composition and regulation of energy intake and its direct and independent effect on lipid profile is still not confirmed. According to this fact that AgRP has a very important effect on appetite and weight adjustment, and also due to the lack of definite results about the effect of HIIT on this variables and its relationship with anthropometric variables, the purpose of this study was to investigate the effect of 8-week HIIT on serum AgRP levels, total cholesterol, low (LDL), –very low (VLDL) and –high (HDL) density lipoproteins and some of body composition indices in overweight and obese men.
Materials and Methods: this quasi-experimental study with pre-test and post-test design including of two groups of interval and control. The study population consisted of 30-35 year-old men with a body mass index (BMI) of 25–35 kg/m2. Among the volunteers to participate in the study which had the inclusion criteria, according to the G*power software, the number of sample was 36. Participants were randomly assigned into two groups of HIIT (n=18) and control (n=18) group. During the period of the study, 2 HIIT participants were excluded from the study due to the irregularly participation during sessions and 2 control person also were excluded from the study based on the absence in the final blood sampling. The intervention included a 2-week familiarization period followed by 8-week of HIIT that performed by repeated 3 sessions per week. The training sessions were conducted under the supervision of the researcher. The training protocol in the first week of the familiarization consisted of 1 set of runs with 3 repetitions, each repeated for 10 seconds and with intensity of 50-70 % maximal oxygen uptake speed (vVO2max). The rest interval between repetitions was considered 60 seconds. Moreover, in the second week of the familiarization, participants performed 2 sets of HIIT, that each consisted of 3 repetitions of running for 5 seconds at 70-90 % vVO2max. The rest interval between each set and the repetition of 90 seconds was determined. After the third week, the rest of the protocol as a main training (HIIT) consisted of 2-4 sets in each session and 5 repetitions for 20 seconds with intensity of 100-140 % vVO2max. The rest interval between each set of rest (inactive and active rest) and repeat (passive rest) were 180 and 60-80 seconds, respectively. Blood samples (10 ml) were collected after 12 hours of fasting at the beginning of the study and 48 hours after the last training session by a laboratory expert from the antecubital vein of participants. Blood samples were permitted to undergo clotting at room temperature for approximately 30-60 min prior to centrifugation at 3,000 RPM for 10 min. Subsequently, serum was distributed into 1.8-mL aliquots and stored at a temperature of -20°C until biochemical assays were performed. Serum concentrations of variables were measured using enzyme-linked immunosorbent assays (ELISA) (RayBiotech, USA). Also, body composition including weight, BMI, and body fat percentage was measured in fasting state using bioelectrical impedance analysis (230 body composition analyzer; Inbody Co. Ltdˏ Taiwan). For statistical analysis the Shapiro–Wilk test was employed to evaluate the normality of the variables which were normally distributed. The analysis of covariance was used to analyze between-group comparisons at the significance level (p<0.05).
Findings: According to the results, BMI (p=0.0001), body fat percentage (p=0.0001), and waist-to-hip ratio (p=0.0001) decreased significantly in the HIIT group compared to the control group (Table 1). Also, a significant increase in the serum levels of AgRP (p=0.0001) and decrease in triglyceride (p=0.0001), total cholesterol (p=0.0001), LDL (p=0.0001), and VLDL (p=0.0001) were observed in the HIIT group compared to the control group, while HDL reduced significantly only in the control group (p=0.0001) (Table 1).
Conclusion: In agreement with the findings of the present study, earlier research has shown that HIIT can enhance serum levels and activity of AgRP. This effect is likely associated with improved insulin sensitivity, alterations in appetite-regulating hormones, and modulation of hypothalamic leptin signaling pathways, that can be lead to increased leptin levels. Moreover, the improvement in lipid profile following HIIT may be explained by elevated lipoprotein lipase activity, enhanced fatty acid oxidation, and improvement in insulin sensitivity. These mechanisms may contribute to reductions in triglycerides, total cholesterol, and LDL, while increasing HDL levels. Furthermore, the significant decrease in waist-to-hip ratio reflects the beneficial impact of HIIT on reducing visceral fat, which is consistent with previous findings. Therefore, HIIT can be used as an effective training strategy in appetite regulation and improvement of lipid profile and body composition indices in overweight and obese men.
Compliance with Ethical Guidelines: The study was approved by the Research Ethics Committee of the University of Tabriz, Iran, which adheres to the Declaration of Helsinki (Ethical Code: IR.TABRIZU.REC.1403.111).
Funding: This research received no specific grant from any funding agency.
Conflicts of Interest: The authors declare no conflicts of interest.
کلیدواژهها [English]
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