Autonomic function in perimenopausal women experiencing vasomotor symptoms

Vasomotor symptoms (VMS, e.g., hot flashes and night sweats) are experienced by ~75% of women throughout menopause and may be linked to the future development of hypertension. A potential mechanism underlying this association is heightened sympathetic outflow and reduced baroreflex function. Although VMS begin during the menopausal transition, to date there are no data examining sympathetic outflow or baroreflex sensitivity in perimenopausal women experiencing VMS. Therefore, the purpose of this study was to test the hypothesis that perimenopausal women with VMS have higher muscle sympathetic nerve activity (MSNA) and reduced baroreflex sensitivity compared to women without VMS (Control). Twelve midlife women (ages 42-56yrs) were classified as perimenopausal using the STRAW+10 criteria. Women self-reported VMS burden using a Likert scale of 0-5 for frequency and severity of both hot flashes and night sweats, wherein higher scores indicate greater symptom burden. Women were separated into two groups based on symptoms scores of either 0-1, occurring ‘never’ or ‘rarely’ with a severity of ‘slight’ to ‘N/A’ (Control, n=7; age 49±4yrs, BMI 23±3kg/m2), or 2-5 where symptoms where occurring ‘occasionally’ to ‘almost always’ with severity of ‘mild’ to ‘extreme’ (VMS, n=5; age 50±5yrs, BMI 24±3kg/m2). We measured MSNA via peroneal microneurography (Control n=4 vs. VMS n=5), heart rate via ECG, and blood pressure (BP) via finger photoplethysmography (Finapres Medical Systems, Amsterdam, The Netherlands). Baroreflex function was assessed during the Valsalva Maneuver; cardiovagal baroreflex sensitivity (cvBRS) was calculated as the slope of the relation between changes in systolic BP and R-R interval during phase IV of the Valsalva, whereas sympathetic baroreflex sensitivity (sBRS) was calculated as MSNA burst frequency divided by the maximal fall in diastolic BP during the Valsalva maneuver. Resting mean arterial BP was not different between groups (Control 85±8 vs. VMS 89±4 mmHg, P=0.35), however resting MSNA burst frequency (Control 11±3 vs. VMS 24±7 bursts/min, P=0.01) and burst incidence (Control 21±11 vs. VMS 39±13 bursts/100 heartbeats, P=0.06) was higher in the VMS group. Although cvBRS was not different between groups (Control 5.9±3.6 vs VMS 8.3±4.0 ms/mmHg, P=0.33), sBRS tended to be greater in VMS (Control -0.36±0.15 vs. VMS -0.66±0.28 bursts/beat/mmHg, P=0.09). These preliminary data suggest perimenopausal women experiencing VMS exhibit higher resting MSNA and sympathetic baroreflex sensitivity. Additional research is needed to understand the impact of VMS and the menopausal transition on autonomic function. Supported by NIH R01 HL 146558 and P20 GM 1131125 This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.