Effects of High-Intensity Interval Training on Adropin, Blood Glucose Markers, Insulin Resistance

Abstract

Background and objectives: Previous investigations have shown that physical activity can improve insulin sensitivity and body composition by reducing the concentration of inflammatory biomarkers. The study aimed at evaluating effects of eight weeks of resistance training and high-intensity interval training on adropin, blood glucose markers, and body composition in overweight females. Methods: sixteen overweight females (mean age: 30 ± 4.3 years and body mass index= 29 ± 2.6 kg/m 2) were randomly assigned to a resistance training group (n=8) and a high-intensity interval training group (n=8). Participants in both groups trained three times a week for eight weeks. Body composition and serum level of blood markers were determined at baseline and after the last training session. Results: Body mass, body fat percentage, and waist-hip ratio decreased significantly in both groups (p<0.05). VO 2max significantly increased in both groups, while the changes in the resistance training group were greater than in the high-intensity interval training group (p<0.05). Insulin and HOMA-IR concentrations decreased significantly in the resistance training group (p<0.05). Conclusion: Eight weeks of both training procedures could significantly decrease body composition markers. However, the training duration was not sufficient to alter fating blood sugar or adropin concentrations. affect body fat percentage compared to HIIT (9). In one study, eight weeks of ET significantly increased serum adropin concentrations in obese adults (23). Fujie et al. (2015) also reported that eight weeks of ET at 60-70% of maximum heart rate increased adropin concentrations in healthy middle-aged and elderly individuals (24). Furthermore, Alizadeh et al. (2018) demonstrated a significant increase in adropin concentrations following ET in overweight females (25). Given the lack of studies on the effects of resistance training (RT) and HIIT on serum concentrations of adropin in obese or overweight individuals, we aimed to compare effects of RT and HIIT on body composition, insulin, and adropin concentrations in overweight females. MATERIALS AND METHODS Twenty-four overweight and obese females (mean age: 30 ± 4.3 years, mean height: 164.8 ± 4.4 cm) participated in the present study. Inclusion criteria included age of between 25 and 35 years and body mass index (BMI) of 25-35. Exclusion criteria were having cardiovascular disease, diabetes, hypertension, sleep disorders, and history of regular exercise in the last six months. Written consent was obtained from all subjects before participation in the study. The study protocol was approved by the Institutional Human Subject Committee of Ferdowsi University of Mashhad and carried out in accordance with the Declaration of Helsinki. Before baseline measurements, the participants were familiarized with the experiments and procedures. Then, they were randomly assigned into a RT group (n=8) and a HIIT group (n=8). The allocation was stratified by BMI of <25.0 or ≥25.0 kg/m 2 , and the sequence was randomized by a computer. Measurements were made at baseline and after eight weeks of training at a specific time. The subjects were instructed not to alter their regular lifestyle and dietary habits during the study. Maximal strength testing was carried out 24 hours after the body composition measurement. For this purpose, the subjects first warmed up for 10 minutes and then performed two attempts to lift heaviest weight, and the number of repetitions was recorded.