Tymchenko S. Heart rate variability and heavy metal content in pupils and students in urban areas.

Heart rate variability (HRV) in urban 10-16 year old pupils and 18-19 year old students related to the lead and cadmium content in the their organism was examined. It was determined that lead and cadmium content in hair in most of the cases was within the normal limits, with the exception of age 10-11 years (exceeded for cadmium) and age of 15-16 years (exceeded for both metals). It was revealed that with the age heart rate variability (HRV) parameters tend to deviate from norm at rest and disbalance of the sympathetic and parasympathetic nervous system (NS) was observed during functional tests. Correlations showed that lead and cadmium in determined concentrations affected HRV more in pupils than in students (0,36<rs<0,58, 0,004<p<0,09). Lead had effect more at age of 10-11 and 18-19 years, cadmium – 15-16 years and both of the metals had the same influence at the age of 12-13 years. Lead mainly influenced on parasympathetic nervous system, while cadmium realized its effects through both and sympathetic and parasympathetic NS.