title: Assessment of the Cardiac Autonomic Nervous System in Mercury-Exposed Individuals via Post-Exercise Heart Rate Recovery.
abstract: OBJECTIVE
  The aim of this study was to assess exercise heart rate recovery (HRR) indices in mercury-exposed individuals when evaluating their cardiac autonomic function.
  
  
  METHODS
  Twenty-eight mercury-exposed individuals and 28 healthy controls were enrolled. All the subjects underwent exercise testing and transthoracic echocardiography. The HRR indices were calculated by subtracting the first- (HRR1), second- (HRR2) and third-minute (HRR3) heart rates from the maximal heart rate. The two groups were evaluated in terms of exercise test parameters, especially HRR, and a correlation analysis was performed between blood, 24-hour urine and hair mercury levels and the test parameters.
  
  
  RESULTS
  The mercury-exposed and control groups were similar in age (37.2 ± 6.6 vs. 36.9 ± 9.0 years), had an identical gender distribution (16 females and 12 males) and similar left ventricular ejection fractions (65.5 ± 3.1 vs. 65.4 ± 3.1%). The mean HRR1 [25.6 ± 6.5 vs. 30.3 ± 8.2 beats per min (bpm); p = 0.009], HRR2 (43.5 ± 5.3 vs. 47.8 ± 5.5 bpm; p = 0.010) and HRR3 (56.8 ± 5.1 vs. 59.4 ± 6.3 bpm; p = 0.016) values were significantly lower in the mercury-exposed group than in the healthy controls. However, there were no significant correlations between blood, urine and hair mercury levels and exercise test parameters.
  
  
  CONCLUSIONS
  Mercury-exposed individuals had lower HRR indices than normal subjects. In these individuals, mercury exposure measurements did not show correlations with the exercise test parameters, but age did show a negative correlation with these parameters. Therefore, cardiac autonomic functions might be involved in cases of mercury exposure.
authors.affiliation: Department of Clinical Toxicology, Ankara Occupational Diseases Hospital, Ankara, Turkey.
authors.forename: Omer Hinc
authors.initials: OH
authors.lastname: Yilmaz
authors.forename: Ugur Nadir
authors.initials: UN
authors.lastname: Karakulak
authors.forename: Engin
authors.initials: E
authors.lastname: Tutkun
authors.forename: Ceylan
authors.initials: C
authors.lastname: Bal
authors.forename: Meside
authors.initials: M
authors.lastname: Gunduzoz
authors.forename: Emine
authors.initials: E
authors.lastname: Ercan Onay
authors.forename: Mehmet
authors.initials: M
authors.lastname: Ayturk
authors.forename: Mujgan
authors.initials: M
authors.lastname: Tek Ozturk
authors.forename: Mehmet Erdem
authors.initials: ME
authors.lastname: Alaguney
mesh_terms: D000328:Adult; D001341:Autonomic Nervous System / Q000187:drug effects* / Q000503:physiopathology*; D001794:Blood Pressure; D003430:Cross-Sectional Studies; D004452:Echocardiography; D015444:Exercise / Q000502:physiology; D005080:Exercise Test; D005260:Female; D006197:Hair / Q000737:chemistry; D006321:Heart / Q000187:drug effects* / Q000503:physiopathology*; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006801:Humans; D008297:Male; D008628:Mercury / Q000032:analysis; D008630:Mercury Poisoning / Q000503:physiopathology*; D008875:Middle Aged
chemical_list: D008628:Mercury