[Study on the changes of heart-rate in lead-exposed workers]

ECG examination and questionnaires survey were performed among lead-exposed workers in order to assess whether moderate occupational lead exposure may cause autonomic nervous system (ANS) dysfunction. The tests included; 1. heart-rate response to Valsalva manoeuvre (HR-V); 2. heart-rate variation during deep breathing (HR-DB); 3. immediate heart-rate response to immediate stand up (30:15 or Max:Min). The results did not show any evidence that lead exposure is related to ANS dysfunction. There was no significant difference between the exposed workers and controls who were with the same ages (P > 0.05). The important cause for ANS dysfunction was aging.