The Effects of High-Intensity Interval Training on Cardiorespiratory Fitness and IL-6 in Adolescents

Abstract

Cardiovascular disease (CVD) , as a cause of death and illness, is increasing, which is also associated with lower levels of cardiorespiratory fitness (CRF). Physical exercise can improve CRF and spur increases IL-6 (an anti-inflammatory) induced through this same means, which therefore reduces the risk of non-communicable diseases. In addition, high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) have a positive effect on health. This study aims to compare the effect of HIIT versus MICT on CRF and the acute response to exercise-induced plasma IL-6 in healthy and untrained adolescents. Methods: An experimental study with a pre-post design was conducted on 60 untrained and healthy adolescents aged 16.1 ± 0.4. The groups had been trained for 6 weeks with a frequency of three days weekly, while V O2max and blood sampling were performed before and after this activity. The CRF was tested using a multi stage fitness test (MFT), and IL-6 plasma levels were measured with ELISA methods. Results: HIIT increased CRF from 31.2 ± 5.8 to 35.6 ± 6.9 mL / kg / min (p <0.001) and MICT elevated V O2max from 32.3 ± 6.8 to 37.3 ± 6.7 mL / kg / min (p <0.001). In fact, there was no significant difference (p = 0.292) between the two types of training. There was no change in the acute response of the IL-6 at the time of the first and last exercise in both groups. Conclusion: Teenagers need to practice the HIIT and MICT training to reap the associated health benefits. The acute inflammatory response to exercise did not increase significantly, but there were elevated levels of plasma IL-6 afterward.