Reflexo pressor do exercício físico em mulheres com hipotireoidismo subclínico

Abstract

INTRODUCTION: Patients with subclinical hypothyroidism (SCH) may show changes in the cardiovascular system. Thus, the aim of this study was to evaluate the integrity of the pressor reflex exercise in women with SCH. METHODS: Were evaluated eighteen women with SCH (Group SCH) and twenty euthyroid women (Group Control), matched for age (37 ± 11 vs. 38 ± 11 years; p=0.907, respectively), body mass index (26 ± 5 vs. 24 ± 4 kg/m2; p=0.221, respectively) and level of physical activity (6,93 ± 0,81 vs. 7,66 ± 1,14, p=0,063, respectively). Blood pressure was measured every minute by oscillometry (DIXTAL2023®), heart rate measured continuously by electrocardiogram (DIXTAL2023®) and forearm blood flow by the technique of venous occlusion plethysmography (Hokanson®). In forearm vascular conductance was calculated by dividing the forearm blood flow by the mean arterial pressure multiplied by 100. Registering these variables from baseline for 3 minutes followed by 3 minutes of exercise, the protocols of passive exercise, isometric exercise at 10% of maximal voluntary contraction of forearm exercise at 30% maximal voluntary contraction of the forearm were performed and circulatory occlusion for 2 minutes post-isometric physical exercise to 30%. Two-factor ANOVA was used to test differences, significant considering p< 0.05. RESULTS: During the passive exercise, systolic blood pressure, diastolic and mean suffered significant decline, but similar between SCH and Control groups. The heart rate, forearm blood flow and vascular conductance of the forearm showed no change during the protocol of passive exercise. During mild exercise systolic blood pressure did not undergo any changes, diastolic blood pressure was significantly different between the SCH and Control groups. The values of mean arterial pressure, heart rate, forearm blood flow and vascular conductance of the forearm showed a significant increase and behaved similarly. During exercise of moderate intensity values of systolic, diastolic, mean, forearm blood flow and vascular conductance of the forearm increased significantly and similarly between SCH and Control groups. However, the heart rate behavior was significantly different between the SCH and Control groups, however, both groups showed a significant increase in heart rate from baseline. To circulatory occlusion groups had an increase in systolic blood pressure, diastolic and mean, but with similar behavior. CONCLUSION: Women with SCH have pressor reflex upright exercise.