Sportmedizin im Wandel

Abstract

Objective: Assessment of heart rate variability (HRV) is increasingly used to evaluate dynamic features of cardiovascular (cv) control mechanisms and offers a unique insight into autonomic cv modulation in health and diseases. Regular exercise is known to positively influence hemodynamics and various cv risk factors. The present study aimed to evaluate the efficacy of a nine-month moderate interval-training program on HRV in elementary school children.Methods: 68 students (aged 8.60.5 years, 49% girls, BMI 17.92.5kg/m2), were randomized into intervention (IG) (n=34) and control (KG) (n=34) groups. Both IG and KG had regular physical education classes (PE) (3x45min/week). During a nine-month intervention period IG,received an additional exercise intervention program (2x45min/week). Time and frequency domain measures of HRV were obtained before and after the intervention program.Results: In contrast to KG, IG showed positive modifications of HRV parameters. After the intervention, High FrequencyPower (HF-Power) increased by 7.5% (p<0.001) and Low Frequency-Power (LF-Power) decreased by 3.6% (p<0.026) in IG. After the nine-month intervention, the IG and KG showed differences in HF-Power (p<0.001) and LF-Power (p<0.003) alterations.Conclusion: In elementary school children, an additional regular moderate intensity interval training had favorable effects on measures of cardiac autonomic control due to increasing cardiac vagal activity. Therefore, exercise time in children should be increased as early as possible to positively influence cardiac autonomic function and potentially reduce cardiovascular morbidity in later life.KEY WORDS: Heart Rate Variability, Autonomic Modulation, Exercise Intervention, Elementary School Children