[Effect of chronic lead poisoning on the parameters of heart rate variability].

BACKGROUND

The dysfunction of the autonomic nervous system is one of the effects of chronic exposure to lead. Heart rate variability (HRV) is a non-invasive method used to estimate the autonomic system. The aim of the study was to estimate HRV in people occupationally exposed to lead.

MATERIALS AND

METHODS

The study group included 43 copper-smelters and 43 healthy subjects matched individually. A 24-hour ECG Holter monitoring was performed in all men.

RESULTS

The HRV time analysis in a 24-hour observation, as well as for daily activities (6:00-22:00) and nocturnal sleep (22:00-6:00) showed that pNN50 parameter, an estimator of the vagus nerve function, was significantly lower in copper-smelters than in healthy subjects (p < 0.05). The majority of time and spectral HRV parameters, estimated at 15-min intervals during day- and night-time in the group of lead exposed men, were lower than in the control group (p < 0.05).

CONCLUSIONS

In subjects occupationally exposed to lead, HRV is lower than in healthy men, which results rather from the decreased parasympathetic than from the increased sympathetic activity.