Mucociliary clearance and its relation with the level of physical activity in daily life in healthy smokers and nonsmokers

Objectives: To investigate the relationship between mucociliary transport and physical activity in daily life (PADL) in smokers and nonsmokers.Methods: Fifty-two current smokers were submitted to an assessment of mucociliary transport (saccharin transit time, STT), carbon monoxide levels in the exhaled air, lung function and smoking history. In addition, subjects kept a pedometer worn at the waist for six days in order to determine their level of PADL (steps/day). The tests were also performed on 30 matched healthy nonsmokers who served as control group.Results: Light smokers (<= 15 cigarettes/day) had a STT of 9 (7-11) min (median [confidence interval]), which was similar to nonsmokers (8 [8-11] min; p = 0.8). Both moderate (16-25 cigarettes/day) and heavy (>25 cigarettes/day) smokers had a significantly higher STT (13 [11-17] min and 13 [10-21] min, respectively) than nonsmokers and light smokers (p < 0.05 for all). There was no difference in the number of steps/day between any of the groups (p > 0.05 for all). In the general group of smokers, STT was not significantly correlated with PADL, pack/years index, years of smoking or age (r < -0.23; p > 0.09 for all). There was significant negative correlation between STT and PADL only in light smokers (r = -0.55; p = 0.02) and nonsmokers (r = -0.42; p = 0.02), but not in moderate and heavy smokers.Conclusion: In light smokers and non-smokers, better mucociliary function is associated to higher daily physical activity level, as opposed to the decreased mucociliary function observed in smokers, i.e., those with moderate and heavy cigarette consumption. (C) 2011 Sociedade Portuguesa de Pneumologia. Published by Elsevier Espana, S. L. All rights reserved.