Is volcanic air pollution associated with decreased heart-rate variability?

• Published in: Heart Asia 2010-01, Vol.2 (1), p.36-41
• Main Authors: Chow, Dominic C, Grandinetti, Andrew, Fernandez, Ed, Sutton, A J, Elias, Tamar, Brooks, Barbara, Tam, Elizabeth K
• Format: Article
• Language: English
• Subjects: Original Research
• ISSN: 1759-1104; 1759-1104
• DOI: 10.1136/ha.2009.001172

ObjectivesTo determine the autonomic cardiovascular control among residents of Hawaii who are exposed to varying levels of volcanic air pollution (vog), which consists largely of sulfur dioxide (SO2) and acid aerosols.MethodsIn a cross-sectional study between April 2006 and June 2008, the authors measured cardiovagal autonomic function by heart-rate variability (HRV) in 72 healthy individuals who lived in four exposure zones on Hawaii Island: vog-free (n=18); episodic exposure to SO2 >200 ppb and acid aerosol (n=19); chronic exposure to SO2 ≥30 ppb and acid aerosol (n=15); and chronic exposure to acid aerosols (n=20). Individuals with diabetes or heart disease, or who had smoked in the preceding month were excluded. HRV was measured in all subjects during rest, paced breathing and active standing (Ewing manoeuvre). HRV was analysed in time and frequency domains and compared between the four exposure zones.ResultsThere were no significant differences between exposure zones in HRV, in either time or frequency domains, even after adjustment for age, gender, ethnicity and body mass index. There was no significant HRV change in three individuals in whom HRV was measured before and during an exposure to combined SO2 100–250 ppb and concentration of respirable particles of diameter ≤2.5 μ (PM2.5) >500 μg/m3. Age was significantly correlated with time-domain parameters during paced breathing and the Ewing manoeuvre.ConclusionsThis study of healthy individuals found no appreciable effects of vog on the autonomic nervous system.