Comparing Cerebral Blood Flow Auto Regulation in Young Males and Females

Introduction: Cerebral autoregulation (CA) and Mean Cerebral Blood Flow Velocity in males and females are still under controversy. The present study was scheduled to address the effect of sex on these parameters.

Materials and Methods: The Present study was interventional and performed on 30 healthy volunteers (15 males aging from 20-30 yrs and mean age of 23.9±3 years old and 15 females aging from 20 to 30 yrs and mean age of 24.2±2.5 years old). Flow velocity in middle cerebral artery (MCA) was assessed using transcranial Doppler (TCD) ultrasonography with a 2MHz probe. Eckberg’s neck suction device was utilized to stimulate carotid baroreceptors and a standard electrocardiograph, which recorded lead Π ECG traces, demonstrated carotid baroreflex response. In this study mean blood flow velocity in MCA represented the amount of brain blood flow. To analyze the data ANOVA and t-test were employed.

Results: There was a significant reduction in the heart rate after carotid baroreceptors stimulation in both sexes (P<0.001). The difference between the mean blood flow velocity oscillations of both groups in MCA during carotid baroreceptors stimulation was not statistically significant. However this was significantly higher in females both in baseline state and during stimulation (P<0.05).

Conclusion: The results indicated the high efficacy of cerebral blood flow autoregulation and higher cerebral blood flow velocity in females which is probably due to estrogen hormone.