Abstract
Acute smoke exposure causes changes in autonomic modulation in young people, who recover after 30 minutes. However, it is unclear how acute smoke exposure affects this system in adult smokers at an older age and with the effects of chronic smoking. Aim: To evaluate the acute effects of smoking on an autonomic modulation in adult smokers and to correlate anthropometric and smoking characteristics with autonomic modulation of these subjects. Methods: Autonomic modulation by heart rate variability (HRV) was evaluated in 23 adult smokers (45.5±3years,30.3±13.7pack-years and 28.7±5years of smoking,mean±standard deviation,14 women/9 men) in the sitting position after 12 hours of smoking abstinence, for 30 minutes at rest, 20 minutes while smoking and 30 minutes after smoking. Repeated-measures ANOVA followed by Tukey's test or Friedman's test followed by Dunn's test were used and for correlation Pearson's or Spearman's correlation were used, with P<0.05. Results: During smoking there was a decrease in global variability (SD2,SDNN and LFms2;P<0.05), parasympathetic activity (SD1,RMSS,HFms2 and HFnu;P<0.001) and RR intervals (P<0.001), besides increase in sympathetic activity represented by LFnu and LF/HF ratio (P<0.001). The plot visual analysis showed a reduction in the dispersion of RR intervals, demonstrating lesser variability. No recovery was found in RR intervals, SDNN, RMSSD, SD1 and plot, 30 minutes after smoking. Also, no significant correlations were found between HRV indices and anthropometric and smoking characteristics. Conclusion: Autonomic modulation was partially recovered in adult smokers 30 minutes after acute smoke exposure, with a persistent reduction in parasympathetic activity during the period studied.
- © 2014 ERS
