Resposta hemodinâmica durante exercício físico isométrico em tabagistas fisicamente ativos

Abstract

BACKGROUND: According to the World Health Organization, smoking is the leading cause of avoidable death worldwide. Many times this is secondary to cardiovascular problems, since it's capable of changing the hemodynamic balance as well as promoting an endothelial dysfunction. Nevertheless, it’s known that the regular practice of exercise is a potential strategy which can reduce the harmful effects of smoking. OBJECTIVE: To compare the hemodynamic response and the arterial blood pressure metaboreflex control among sedentary smokers (SS), fiscally active smokers (FAS) and sedentary non-smokers (SNS) during isometric exercise. METHODS: A cross sectional, observational study in which a convenience sample was composed of male SS, FAS SNS. First of all, hemodynamic variables ware collected for 10 minutes using Biopac and the Digital Infrared Photoplethysmography method (Finometer Pro). Then, the volunteers were submitted to a baseline evaluation followed by three minutes of isometric manual prehension, with a dynamometer loaded with 30% of maximal voluntary handgrip muscular contraction, and two minutes of circulatory occlusion. During the experimental protocol, heart rate (HR), systolic (SABP), diastolic (DABP) and mean (MABP) blood pressure ware measured by the oscillometric method (DIXTAL 2022) and the muscular blood flow (MBF) was measured by venous occlusion plethysmography (Hokanson). Forearm vascular conductance (FVC) was estimate splitting forearm blood flow by mean arterial blood pressure multiplied for 100. The data are presented as mean ± and standard error. For the statistical analysis was use the following tests: Shapiro-Wilk, Test t student, ANOVA one-way, ANOVA two-way followed by Bonferroni post hoc. A significance P≤0,05 and all statistical analysis was runned on SPSS 22.0. RESULTS: 15 SS (28±2 years), 7 FAS (24±2 years) and 16 SNS (26±2 years) was evaluated pared by age and body mass index. During the exercise SABP, DABP and MABP raise similarly between the groups SS, FAS, SNS (SABP - time: P<0,001, group: P=0,92; DABP - time: P<0,001, group: P=0,65; MABP - time: P<0,001, group: P=0,77). In the same way as MBF and FVC (MBF - time: P<0,001, group: P=0,91; FVC - time: P<0,02, group: P=0,92). Although rising in all groups during exercise (time - SS: P<0,001; FAS: P<0,001; SNS: P<0,001), HR on the other hand presented lower values on the FAS than in the SNS group (group: P=0,02). During metoberreflex stimulus SABF and DABF also had similar higher values then the baseline in all groups (SABP - time: P<0,001, group: P=0,88; DABP - time: P<0,001, group: P=0,30). CONCLUSION: Smokers has a preserved metaboreflex and hemodynamic response during isometric handgrip exercise. Moreover, FAS presented lower HR values during exercise compared do SNS.