Muscle Sympathetic Nerve Activity is Elevated in Females with Physical Menopause Symptoms

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Introduction Multiple symptoms accompany menopause, including vasomotor symptoms (VMS), physical symptoms, psychosocial symptoms and sexual dysfunction. Previous studies show that experiencing VMS may increase the risks for hypertension and cardiovascular disease (CVD); however, it is unclear whether physical menopausal symptoms, such as weight gain, lack of energy, or reduced muscular strength, contribute to CVD risk. Furthermore, muscle sympathetic nerve activity (MSNA) is elevated with CVD, but the relationship between menopause symptoms and MSNA is unknown. Thus, the aim of our study was to determine if physical menopausal symptoms are correlated with MSNA in postmenopausal females. Methods Eight postmenopausal females (age 63±1yr; menopause age 53±2yr) attended two study visits. The first visit included written informed consent, completion of the Menopause-Specific Quality of Life (MENQOL) and Minnesota Leisure Time Physical Activity (MLTPAQ) Questionnaires, and blood draws to measure sex hormone levels. The MENQOL asks participants to rate how bothered they feel in four areas of symptoms: vasomotor (i.e., VMS), psychosocial, physical, and sexual. The absence of a symptom corresponds with a score of 1 point, whereas a present symptom is rated according to how bothersome it is and is scored from 2-8 points. The MLTPAQ estimates caloric expenditure based on reported habitual physical activity. The second visit was conducted in the morning after an overnight fast and abstinence of alcohol, caffeine and exercise for 12 hours and included measurements of continuous noninvasive BP, heart rate via a 3-lead electrocardiography (ADInstruments, Colorado Springs, CO) and MSNA of the peroneal nerve via microneurography during a 10-minute period of quiet rest. Results Total MENQOL scores ranged from 1.3-2.4 on a 1-8 scale; physical symptom scores ranged from 1.1 to 3.4; and VMS ranged from 1.0-1.7. Body mass index (BMI, kg/m2) was 24±2. Levels of estradiol, total estrogens, testosterone, total estrogens: testosterone ratio, and MLTPAQ were not different between the females. Average mean arterial pressure was (101±5mmHg) and MSNA burst frequency was 29 bursts/min). In addition, MSNA burst frequency correlated with the MENQOL scores for physical symptoms (r=0.73, p=0.04), but not other menopausal symptoms, including VMS (p>0.05), indicating that females with more severe physical symptoms had greater MSNA. Conclusion Although females with VMS have greater CVD risk than those without VMS, data from this small sample of females suggests that reported physical symptoms rather than VMS were elevated with resting MSNA and were strongly associated with MSNA. These findings suggest that females who experience physical menopause symptoms may demonstrate autonomic dysregulation which could contribute to CVD risk.