Exercise adaptations and TGF-β1 levels in recreational cyclists

BACKGROUND: Cycling is a physical exercise that is widely performed to improve physical fitness. Regular physical exercise will lead to adaptations to exercise. This adaptation is useful in suppressing the production of reactive oxygen stress (ROS) generated in response to cellular metabolism that uses oxygen. Transforming growth factor beta-1 (TGF-β1) plays a role in increasing the production of ROS, thus, when the concentration is low, it would lead to an improvement in physical fitness. This study aims to compare levels of TGF-β1 between recreational cyclists and sedentary groups. In addition, this research also compares several other parameters, which are fasting blood sugar levels and lipid profiles (triglycerides, total cholesterol, HDL cholesterol, and LDL cholesterol) between cyclists and sedentaries. METHODS: This was an observational analytical study with a cross-sectional design. The research subjects consisted of 2 groups, each consisting of 21 participants, namely the recreational cyclist and the sedentary group. Anthropometric examinations were carried out, including body weight, height, body mass index, waist circumference, and body fat percentage. Fasting blood glucose concentration and lipid profile (Triglyceride – TG, Total Cholesterol – Total C, HDL Cholesterol – HDL-C, and LDL Cholesterol – LDL-C) were determined by the enzymatic colorimetric methods, and TGF-β1 levels were determined using the fluorescence of specific antibodies for TGF-β1 (pg/ml) using ELISA method. Statistical analysis was performed using IBM SPSS v. 25. RESULTS: The anthropometric variables, other than body height, did not differ significantly between the two groups, so did the fasting blood glucose concentration. Nevertheless, the lipid profile (TG, Total C, HDL-C and LDL-C) were found to be significantly better in the cyclist group (p < 0.05). The mean level of TGF-β1 in recreational cyclists was 8, 908.48 pg/ml, lower than the control group, 10, 229.28 pg/ml. The results of the unpaired t-test showed significant mean differences between the two groups, (p = 0.001; p < 0.05). CONCLUSION: The levels of TGF-β1 in the recreational cyclist group were lower than the sedentary group. Regular physical exercise will trigger exercise adaptations that can suppress latent TGF-β1 activation.