Sleep disturbance and sympathetic neural reactivity in postmenopausal females

Abstract

Sleep disturbance, one of the most common menopausal symptoms, contributes to autonomic dysfunction and is linked to hypertension and cardiovascular risk. Longitudinal studies suggest that hyperreactivity of blood pressure (BP) to a stressor can predict the future development of hypertension. It remains unknown if postmenopausal females who experience sleep disturbance (SDG) demonstrate greater hemodynamic and sympathetic neural hyperreactivity to a stressor. We hypothesized that postmenopausal females with reported sleep disturbance would exhibit increased hemodynamic and sympathetic reactivity to a stressor compared with postmenopausal females without sleep disturbance (non-SDG). Fifty-five postmenopausal females (age, 62 ± 4 yr old; SDG, n = 36; non-SDG; n = 19) completed two study visits. The Menopause-Specific Quality of Life Questionnaire (MENQOL) was used to assess the presence of sleep disturbance (MENQOL sleep scale, ≥2 units). Beat-to-beat BP (finger plethysmography), heart rate (HR; electrocardiogram), and muscle sympathetic nerve activity (MSNA; microneurography; SDG, n = 25; non-SDG, n = 15) were continuously measured during a 10-min baseline and 2-min stressor (cold pressor test; CPT) in both groups. Menopause age and body mass index were similar between groups (P > 0.05). There were no differences between resting BP, HR, or MSNA (P > 0.05). HR and BP reactivity were not different between SDG and non-SDG (P > 0.05). In contrast, MSNA reactivity had a more rapid increase in the first 30 s of the CPT in the SDG (burst incidence, Δ10.2 ± 14.8 bursts/100 hb) compared with the non-SDG (burst incidence, Δ4.0 ± 14.8 bursts/100 hb, time × group, P = 0.011). Our results demonstrate a more rapid sympathetic neural reactivity to a CPT in postmenopausal females with perceived sleep disturbance, a finding that aligns with and advances recent evidence that sleep disturbance is associated with sympathetic neural hyperactivity in postmenopausal females.NEW & NOTEWORTHY This is the first study to demonstrate that muscle sympathetic nerve activity (MSNA) to a cold pressor test is augmented in postmenopausal females with perceived sleep disturbance. The more rapid increase in MSNA reactivity during the cold pressor test in the sleep disturbance group was present despite similar increases in the perceived pain levels between groups. Baseline MSNA burst incidence and burst frequency, as well as blood pressure and heart rate, were similar between the sleep disturbance and nonsleep disturbance groups.

Keywords: autonomic nervous system; cardiovascular risk; menopause symptoms; microneurography; women’s health.

Figure 1.

A repeated-measures ANOVA was used to assess the changes in blood pressure (BP) and heart rate (HR) during the cold pressor test (CPT). The absolute changes in systolic BP (SBP, A), diastolic BP (DBP, B), mean arterial pressure (MAP, C), and HR (D) from baseline throughout the 2-min CPT are presented. Systolic BP, DBP, MAP, and HR increased throughout CPT from baseline (time effect, P < 0.001), but these increases were not different between groups. SDG, sleep disturbance group (n = 36); non-SDG, non-sleep disturbance group (n = 19). ANOVA, analysis of variance.

Figure 2.

A repeated-measures ANOVA was used to assess the changes in perceived pain during the cold pressor test (CPT). The absolute changes in perceived pain from baseline throughout the 2-min CPT are presented. Pain increased throughout the CPT from baseline (time effect, P < 0.001), but these increases were not different between groups. SDG, sleep disturbance group (n = 36); non-SDG, non-sleep disturbance group (n = 19). ANOVA, analysis of variance.

Figure 3.

A repeated-measures ANOVA was used to assess the changes in muscle sympathetic nerve activity (MSNA) during the cold pressor test (CPT). A: muscle sympathetic nerve activity burst incidence (BI) was greater for the sleep disturbance group (SDG) compared with the non-SDG (group × time interaction, P = 0.011). SDG had significant increases in MSNA BI from baseline to 30–120 s (P < 0.05 for all time points). Non-SDG demonstrated an increase in MSNA BI from 90 to 120 s (P < 0.05) but not at 30 and 60 s (P > 0.05). B: divergence in MSNA BI reactivity was observed at 30 s in SDG compared with the non-SDG group during the CPT (P = 0.012). C: muscle sympathetic nerve activity burst frequency (BF) increased more rapidly for the SDG compared with the non-SDG (group × time interaction, P = 0.027). ^#Significant difference between group at 30 s of the CPT; ^asignificant increase from baseline in the SDG; and ^bsignificant increase from baseline in the non-SDG. SDG (n = 25); non-SDG (n = 15). D: similar to MSNA BI, MSNA BF tended to increase more at 30 s in the SDG compared with the non-SDG group (P = 0.054). ANOVA, analysis of variance.