Seasonal and secular variations in selected indicators of the cardiovascular system among 7-11 years old children

Abstract

The aim was to study seasonal variations in selected indicators of the cardiovascular system (CVS) in primary school students over 5 academic years and compare the findings with the results obtained in 2004-2007. Methods. Heart rate (HR) and its variability, blood pressure (BP) and its variability and cardiac performance were studied using spiroarteriocardiorhythmograph (SACR). Data were collected in late March - early April and late September - early October. The measurements were taken in in 2016-2019 (n=214, 701 measurements) and in 2004-2007 (n=317, 810 measurements). The analysis of the dynamics of semiannual changes ("delta" indicators, in% of the initial level) of CVS indicators of schoolchildren was carried out. As a comparison group, we used adult women (sample size -285 people), surveyed once in different seasons in 2002-2012. Results. Seasonal variability was revealed only for systolic blood pressure and LF / HF ratio reflecting the level of autonomic regulation of the cardiovascular system. In 2016-2019, in the sample of primary school students, an increase in systolic blood pressure over the school year (autumn - spring) and a decrease in LF / HF (in 2 nd - 5th grades ) was fixed. However, in 2004-2007 in children of the same age, seasonal changes had the opposite direction - a decrease in systolic blood pressure over the school year and an increase in LF / HF (in 1st - 5th grades), which corresponds to the seasonal variation of these indicators in adults. Conclusion. The obtained data showed a change in seasonal variability of the functional state of the CVS in primary school children. It has been suggested that such changes could be related to the computerization of education, but further research is warranted.