Effects of LICT-BFR on cardiopulmonary fitness and immune function in youth

Abstract

Cardiopulmonary fitness (CRF) is on the decline among youth. This study aimed to investigate the effects of a low-intensity serial blood flow restriction training exercise protocol on CRF and body composition indices in youth. It also aimed to reveal changes in immune status following low-intensity continuous training exercise in adolescents, shedding light on the regulation of human immunity by exercise. We recruited 50 non-smoking, healthy, and non-exercising young volunteers and randomly divided them into a low-intensity continuous training group (LICT-BFR, n = 25) and a no-exercise Control group (n = 25), with the experimental intervention lasting for ten weeks. Physical function was assessed before and after the intervention. Peripheral blood leukocytes were analyzed for microRNA (miRNA) using Agilent human microRNA 2.0 and genetic software. MiRNA quantification was conducted through reverse transcription real-time quantitative polymerase chain reaction (RT-qPCR). Flow cytometry was used to measure the percentage of various lymphocytes. The results showed that maximum oxygen uptake (VO2 max, p < 0.01) and the percentage of body fat (p < 0.05) were significantly higher in the exercise group compared to the Control group. The LICT-BFR group exhibited a significant decrease in fat mass and visceral fat area (p < 0.05) and an increase in muscle mass (p < 0.05) compared to the Control group. Additionally, six miRNAs (hsa-miR150-5p, 31-5p, 3659, 4419a, 650, and 8485) exhibited reduced expression, with miR-150 showing a significant decrease identified by RT-qPCR (p = 0.021). The percentage of CD3 + T cells was lower in the LICT-BFR group than in the non-exercising subjects (p < 0.001). However, the CD4 + to CD8 + ratio and the percentage of CD4 + T cells showed no significant differences between these two groups. In summary, low-intensity blood flow-restricted continuous training improved CRF in youth and resulted in a statistically significant reduction in T cell numbers and hsa-miR150-5p expression during prolonged exercise training. LICT-BFR was found to modulate the immune system by suppressing T cell and hsa-miR150-5p levels. This study supports the use of low-intensity blood flow restriction continuous training as an ideal exercise protocol.