Female sex and fluctuations in ovarian hormones across the menstrual cycle do not influence the magnitude of carotid baroreflex resetting during dynamic exercise, though women exhibit greater baroreflex control of heart rate.
Observational (n=34)
No
Does sex or ovarian hormone fluctuation influence carotid baroreflex resetting and function during dynamic exercise in healthy young adults?
Sex and fluctuations in ovarian hormones do not influence exercise resetting of the baroreflex, although women exhibit greater carotid baroreflex control of heart rate during exercise.
Absolute Event Rate: 68% vs 81%
p-value: p=>0.05
To date, no studies have examined whether there are either sex- or ovarian hormone-related alterations in arterial baroreflex resetting and function during dynamic exercise. Thus we studied 16 young men and 18 young women at rest and during leg cycling at 50% heart rate (HR) reserve. In addition, 10 women were studied at three different phases of the menstrual cycle. Five-second pulses of neck pressure (NP) and neck suction (NS) from +40 to -80 Torr were applied to determine full carotid baroreflex (CBR) stimulus response curves. An upward and rightward resetting of the CBR function curve was observed during exercise in all groups with a similar magnitude of CBR resetting for mean arterial pressure (MAP) and HR between sexes (P > 0.05) and at different phases of the menstrual cycle (P > 0.05). For CBR control of MAP, women exhibited augmented pressor responses to NP at rest and exercise during mid-luteal compared with early and late follicular phases. For CBR control of HR, there was a greater bradycardic response to NS in women across all menstrual cycle phases with the operating point (OP) located further away from centering point (CP) on the CBR-HR curve during rest (OP-CP; in mmHg: -13 ± 3 women vs. -3 ± 3 men; P < 0.05) and exercise (in mmHg: -31 ± 2 women vs. -15 ± 3 men; P < 0.05). Collectively, these findings suggest that sex and fluctuations in ovarian hormones do not influence exercise resetting of the baroreflex. However, women exhibited greater CBR control of HR during exercise, specifically against acute hypertension, an effect that was present throughout the menstrual cycle.
Kim et al. (Fri,) conducted a observational in Healthy (n=34). Female sex and ovarian hormone fluctuations vs. Male sex and different menstrual cycle phases was evaluated on Magnitude of carotid baroreflex resetting for mean arterial pressure during exercise (in a.u.) (p=>0.05). Female sex and fluctuations in ovarian hormones across the menstrual cycle do not influence the magnitude of carotid baroreflex resetting during dynamic exercise, though women exhibit greater baroreflex control of heart rate.