Effects of School-Based High-Intensity Interval Training on Hemodynamic Parameters and Heart Rate Variability: A Randomized Controlled Trial.

ABSTRACT: Ketelhut, S, Ketelhut, K, Ketelhut, SR, and Ketelhut, RG. Effects of school-based high-intensity interval training on hemodynamic parameters and heart rate variability: A randomized controlled trial. J Strength Cond Res 38(6): 1033-1040, 2024-The purpose of this study was to assess the effects of a child-specific school-based high-intensity interval training (HIIT) implemented into physical education (PE) classes on various hemodynamic parameters and heart rate variability indices. Forty-six students (age 11 ± 1 year) were randomized into an intervention (INT n = 22) and a control group (CON n = 24). During a 12-week period, the INT and CON groups participated in regular PE twice weekly (45-90 minutes). The INT group received HIIT during the first 20 minutes of the 2 PE classes. Systolic and diastolic blood pressure, total peripheral resistance, aortic pulse wave velocity (aPWV), heart rate, SD of normal to normal heartbeat intervals, the root mean square of successive differences between normal heartbeats (RMSSD), the proportion of differences between adjacent normal to normal heartbeat intervals of more than 50 ms, low-frequency power, high-frequency power, and the LF/HF ratio were assessed before and after the experimental period. A p value ≤0.05 was considered statistically significant. Forty students (20 INT; 20 CON) were included in the analysis. A significant time × group interaction was detected for aPWV ( p = 0.05, η2 = 0.099), RMSSD ( p = 0.010, η2 = 0.161), low-frequency power ( p = 0.009, η2 = 0.165), high-frequency power ( p < 0.001, η2 = 0.272), and the LF/HF ratio ( p < 0.001, η2 = 0.354). The INT group revealed significant improvements for the respective parameters. School-based HIIT can induce improvements in cardiovascular parameters. These results highlight the potential of embedding HIIT within the school setting, offering a time-efficient exercise intervention.

School-Based Exercise Intervention Improves Blood Pressure and Parameters of Arterial Stiffness in Children: A Randomized Controlled Trial.

PURPOSE: To evaluate the effectiveness of a school-based exercise intervention on endurance performance (EP), blood pressure (BP), and arterial stiffness in children. METHODS: A total of 105 students (mean age = 8.2 [0.6] y; 51% girls; body mass index = 17.8 [3.0] kg/m2) were randomized to the intervention group (IG, n = 51) and control group (CG, n = 54). During a 37-week experimental period, the IG received an exercise intervention (2 × 45 min/wk) in addition to their regular school physical education class (3 × 45 min/wk). EP, peripheral and central BP, pulse pressure, augmentation pressure, augmentation index, and aortic pulse wave velocity were assessed. RESULTS: Following the intervention, significant changes (P < .05) in EP, peripheral and central systolic BP, pulse pressure, augmentation pressure, augmentation index, and aortic pulse wave velocity were found in the IG. Children in the CG displayed significant changes in peripheral and central diastolic BP. An analysis of the baseline-to-post changes revealed significant between-group differences in EP (P < .001), pulse pressure (P = .028), augmentation pressure (P = .007), and aortic pulse wave velocity (P = .037) that favored the IG and in peripheral and central diastolic BP that favored the CG. CONCLUSION: The school-based exercise intervention had beneficial effects not only on EP but also on different hemodynamic parameters.

Effectiveness of Multi-activity, High-intensity Interval Training in School-aged Children.

The present study aimed to evaluate the effectiveness of a school-based multi-activity HIIT on aerobic fitness (AF) and hemodynamic parameters in children. 46 students were randomized into an intervention group (INT) (N=22) and a control group (CON) (N=24). Throughout a 3-month intervention period, both INT and CON participated in the regular physical education classes (PE) twice a week. Only INT received an instructed HIIT during the first 20 min of the PE. In addition to an AF-test, peripheral (pBP) and central (cBP) blood pressure, augmentation pressure (AP), and aortic pulse wave velocity (aPWV) were assessed. Significant differences in intervention effects in favor of INT were detected for AF (7.73, P=0.007), peripheral systolic BP (-6.13 mmHg, P=0.038), central systolic BP (-5.19 mmHg, P = 0.041), AP (-2.02 mmHg, P=0.013), and aPWV (-0.19 m/sec, P=0.031). The regular HITT intervention showed beneficial effects on AF, BP, and parameters of vascular stiffness already in children.