Influence of a submaximal and maximal aerobic exercise session on mucociliary clearance and autonomic function in smokers

ABSTRACT The aim of this study was to evaluate and to correlate the behavior of mucociliary clearance and the autonomic nervous system of smokers after submaximal and maximal aerobic exercise sessions. We evaluated 25 smokers and 15 nonsmokers aged between 30 and 50 years. Both groups were submitted to the saccharin transit time (STT) test and heart rate variability (HRV) before and after a submaximal (six-minute walk test) and maximal (cardiopulmonary test) exercise. Paired t-test or Wilcoxon were used for intragroup analysis and the unpaired t-test or Mann-Whitney for intergroup analysis. The correlation was performed using Pearson or Spearman coefficients (p<0.05). Saccharine transit time reduced significantly after submaximal and maximal exercises in both groups. After the submaximal exercise, both groups presented significant reduction of the RR interval and increased heart rate (HR). In the nonsmoker group there were significant reductions in the RMSSD, HFms² and SD1 indexes. After maximal exercise, both groups showed significant reductions in SDNN, RMSSD, RR, LF and HF interval, in ms² and normalized units, SD1 and SD2, in addition to the increase in HR, LFun, and LF/HF ratio. STT positively correlated with LFms² (r = 0.520, p = 0.008) after the maximal exercise for the smoker group. We concluded, that regardless of the intensity of aerobic exercise, mucociliary clearance increases in smokers, but this alteration seems to be influenced by the autonomic nervous system only during maximum exercise.