CHANGE IN CARDIOVAGAL NERVOUS RESPONSE TO FACIAL COLD STIMULI THROUGHOUT MENSTRUAL CYCLE

Abstract

‹Objective› In previous animal studies, it has been observed that ovarian hormones centrally alter baroreflex modulation of cardiovagal nervous control. If this central action of ovarian hormones is observed in human females, non-baroreflex modulation of cardiovagal nervous control should change with the menstrual cycle. The hypothesis in this study was that cardiovagal nervous response to facial cold stimuli (non-baroreflex modulation) changes throughout menstrual cycle.‹Subjects and methods› Eight young healthy women with a normal menstrual cycle participated in this study. The menstrual cycle was divided into 5 phases (menstrual, follicular, ovulatory, early luteal and late luteal) . Resing ECG RR intervals, cardiovagal nervous activity (by heart rate variability), RR intervals and cardiovagal nervous response to facial cold stimuli were measured during each menstrual phase. RR intervals and cardiovagal nervous response to facial cold stimuli were evaluated paying attention to the “quantity” and “quickness” of the changes.‹Results› There were no phase differences in resting RR intervals and cardiovagal nervous activity. Quantity of RR intervals and cardiovagal nervous response and quickness of. RR intervals to facial cold stimuli did not change throughout the menstrual cycle. The speed of cardiovagal nervous response to facial cold accelerated in the follicular phase, and to the contrary, slowed down in the early luteal phase, ‹Conclusion› These data suggest the speed of cardiovagal nervous response mediated non-baroreflex mechanism changes throughout the menstrual cycle.