We did not observe any difference in LF (ms) component or in LF/HF ratio,A�neither at baseline nor after MBC in both groups.A�The HF n.u. were significantly greater in R+ than inA�Ra�� at baseline (p < 0.01), and increased significantly after MBC only in R+ (F[1,51] = 9.2,A�p < 0.05).
Multiple Regression Analyses
Multiple regression analyses were performed in all subjects at baseline and after the MBC on the HFA�component expressed in absolute units and n.u. AtA�baseline, these analyses showed a significant influence of physical activity (r = 0.52, p < 0.001) andA�height (r = a�� 0.27, p < 0.01) on HF ms and ofA�bronchial responsiveness on HF n.u. (r = a�� 0.28,A�p < 0.01). After the bronchial challenge test, multiple regression analyses demonstrated a significantA�effect of physical activity (r = 0.83, p < 0.0001),A�baseline FVC (r = a�� 0.3, p < 0.005), and smokingA�habits on HF ms (r = a�� 0.19, p < 0.01), whereasA�the HF n.u. was only influenced by the bronchialA�responsiveness (r = a�� 0.51, p < 0.0001).
Discussion Viagra pharmacy
The main finding of this study is that R+ have a significantly higher parasympathetic tone than Ra�� atA�baseline. Interestingly, R+ also showed a significantA�increase of the index of parasympathetic modulation ofA�HR after bronchial challenge, suggesting a significantA�increase in cardiac reactivity. Moreover, there was aA�significant relationship between the HF (n.u.) component of HRV and hyperresponsiveness of the subjects.
Several studies have shown that airway parasympathetic nerves are tonically active during tidal 26 breathing, producing a stable, readily reversible baseline tone of the airway smooth muscles thatA�likely reflects the opposing influences of contractileA�and relaxant airway parasympathetic nerves. AirwayA�smooth muscle is tonically active under resting conditions since its effects can be abolished by atropine or ipratropium bromide infusion. Moreover, electrophysiologic recordings from both preganglionicA�parasympathetic nerves fibers and postganglionicA�parasympathetic ganglion neurones confirm the existence of a persistent outflow of parasympatheticA�nerves activity to the airways. These results supportA�the view that, in humans, airway tone is mainlyA�vagally controlled. Furthermore, parasympatheticA�airway tone appears to be significantly increased inA�asthmatic subjects compared with nonasthmatic sub-jects. In this study, spectral analysis of HRV wasA�used to assess sympathetic/parasympathetic modulation in subjects who performed the bronchial challenge test. This method allows identification of LFA�and HF components. The LF component corresponds mainly to sympathetic modulation and partially to parasympathetic modulation, whereas theA�HF component represents only parasympatheticA�modulation that could also be assessed by short-termA�indices of Poincare plot (SD1).