Cardiovascular adaptations after 10 months of intense school-based physical training for 8-to 10-year-old children

This study examined cardiovascular adaptations in 8- to 10-year-old schoolchildren after 10 months (a full school year) of 3 x 40 minute per week of small-sided ball games (SSG, including football, basketball, and/or floorball) or circuit strength training (CST). The study involved 291 Danish schoolchildren, 8-10 years old, cluster-randomized to SSG (n = 93, 4 schools, 5 classes), CST (n = 83, 4 schools, 4 classes), or a control group (CON, n = 115, 2 schools, 5 classes). Before and after the 10month intervention, resting heart rate and blood pressure measurements were performed as well as comprehensive transthoracic echocardiography and peripheral arterial tonometry (PAT). Analysis of baseline-to-10-months changes showed between-group differences (P < 0.05) after both training interventions in diastolic blood pressure (delta scores: SSG -2.1 +/- 6.0 mm Hg; CST -3.0 +/- 7.1 mm Hg; CON 0.2 +/- 5.3 mm Hg). Moreover, there were between-group differences in delta scores (P < 0.05) in interventricular septum thickness (SSG 0.17 +/- 0.87 mm; CST 0.30 +/- 0.94 mm; CON -0.15 +/- 0.68 mm), left-atrial volume index (SSG 0.32 +/- 5.13 mL/m(2); CON 2.60 +/- 5.94 mL/m (2)), and tricuspid annular plane systolic excursion (SSG -0.4 +/- 3.3 mm; CON: 0.1 +/- 3.6 mm). No significant between-group differences were observed for the PAT-derived reactive hyperemia index. In conclusion, 10 months of 3 x 40 minutes per week of SSG and CST in 8- to 10-year-old children decreased diastolic blood pressure and elicited discrete cardiac adaptations, suggesting that intense physical exercise in school classes can have effects on cardiovascular health in children.