Heart rate variability in workers chronically exposed to lead

Area of Science:

• Environmental Health
• Occupational Medicine
• Cardiology

Background:

• Lead is a known neurotoxin.
• The impact of lead on autonomic nervous system (ANS) activity, assessed via heart rate variability (HRV), remains unclear.
• This study investigates the ANS in individuals with chronic occupational lead exposure.

Purpose of the Study:

• To evaluate the effects of chronic occupational lead exposure on autonomic nervous system function.
• To determine if lead exposure alters heart rate variability (HRV) parameters.

Main Methods:

• 22 copper foundry workers with elevated lead levels and 13 healthy controls underwent 24-hour ambulatory ECG monitoring.
• Lead concentration and free erythrocyte protoporphyrins (FEP) were measured.
• Standard short-term and long-term HRV parameters were analyzed.

Main Results:

• No significant overall differences in HRV parameters were observed between lead-exposed workers and controls.
• In lead-exposed workers, higher lead concentrations correlated negatively with nighttime HRV parameters (SDNN, TP, LF).
• Lead exposure was associated with a reduced physiological increase in HF values from day to night, unlike controls.

Conclusions:

• While overall HRV indices were similar, chronic lead exposure may subtly disturb autonomic nervous system function.
• The blunted nocturnal increase in HF values in exposed workers suggests ANS dysregulation.
• Lead exposure's impact on the age-related HRV patterns observed in controls indicates a potential neurotoxic effect.