Resistance Training and Physical Activity in Postmenopausal Women : Effects on Vasomotor Symptoms, Quality of Life and Microcirculation

Sammanfattning: Background  Menopause is a physiological event, but is associated with bothersome symptoms as well as physical changes that affect women’s health. About 75 % of women experience vasomotor symptoms (hot flushes and night sweats) related to menopause that often reduce quality of life. The vasomotor symptoms may be attributed to dysfunctional temperature regulation centrally in the hypothalamus and peripherally in the skin’s circulation. The most effective treatment for vasomotor symptoms is menopausal hormone therapy, but not all women are able to, or want to, use it.  In addition to the impact on quality of life, studies have associated vasomotor symptoms and menopause with macrovascular endothelial dysfunction. Previous studies on the association of these factors with the skin’s microcirculatory function are small and few. Observational studies have associated physical activity and exercise with less vasomotor symptoms, but the evidence from intervention trials is of low quality and the results are ambiguous. Physical activity has established general health effects, and could potentially decrease vasomotor symptoms by effects on endogenous opioids centrally, and by more efficient thermoregulation peripherally.  The aim of this thesis was to investigate the effect of resistance training on vasomotor symptoms and health-related quality of life in postmenopausal women, and to explore the women’s experiences of the training to find barriers and facilitators. We also aimed to investigate whether the skin’s microcirculatory function differed between women regarding menopausal status, vasomotor symptoms, menopausal hormone therapy, and physical activity.  Material and methods  The first study was an open randomized controlled trial including 65 postmenopausal women with moderate to severe vasomotor symptoms and low physical activity levels. We randomized the women to 15 weeks of resistance training (intervention) or unchanged physical activity (control). The participants registered vasomotor symptoms daily in a diary, and answered health-related quality of life questionnaires at baseline and at 15 weeks. The first 15 women to finish the intervention were recruited to a qualitative study. The women’s experiences of the resistance training intervention were explored in individual interviews after the intervention period, and all were followed-up with telephone interviews after one year. The third study was cross-sectional, including 1148 women from Linköping, 50-64 years old, who participated in the Swedish CArdioPulmonary bioImage Study (SCAPIS). These women answered a questionnaire about menopausal status, vasomotor symptoms and menopausal hormone therapy use, and wore accelerometers for seven days to assess physical activity. The skin’s microcirculation was assessed at rest and during post-occlusive reactive hyperemia.  Results  Moderate to severe vasomotor symptoms per 24 hours decreased significantly more in the group of women randomized to resistance training compared with the control group (mean difference -2.7, 95% CI -4.2 to -1.3). The resistance training group improved in domains of menopause-specific health-related quality of life compared with the control group but there was little impact on generic health-related quality of life. In the qualitative study we found that the vasomotor symptoms acted as a “trigger” for the women to become motivated to exercise. Their motivation then evolved from being driven by hopes of symptom relief into being driven by a wish for general well-being, which was still a driving force after one year. Microvascular function did not differ between postmenopausal and premenopausal women, or between women with or without vasomotor symptoms or menopausal hormone therapy. Women with higher levels of objectively measured and self-reported physical activity had a better reactivity of the skin’s microcirculation. The differences remained significant after adjusting for BMI, smoking, hypertension, diabetes, and education.   Conclusions  Resistance training could be effective for decreasing vasomotor symptoms and improving some aspects of health-related quality of life in motivated postmenopausal women. The vasomotor symptoms themselves spurred motivation to exercise, indicating they present an opportunity to increase physical activity. When a woman seeks medical advice for vasomotor symptoms, this could be a chance for health care professionals to help her initiate or increase exercise. Women who performed more physical activity and exercise had better skin microvascular function, but no association with VMS was found. Future studies are needed to investigate what type and dose of exercise is the most effective to reduce vasomotor symptoms and whether there is a way to predict for whom exercise will or will not be an effective intervention.