Effects of menopause and high-intensity training on insulin sensitivity and muscle metabolism

Role of menopausal hormone therapy in the prevention of postmenopausal osteoporosis

The use of menopausal hormone therapy (MHT) has declined due to concerns about its potential side effects. However, its pivotal role in managing postmenopausal osteoporosis is gaining increased recognition. In this article, we explore how MHT assists postmenopausal women in maintaining bone health and preventing fractures. Recent research indicates that MHT significantly reduces the risk of fractures in women. This benefit is evident regardless of a woman's bone mineral density or their use of progestogens. However, there is limited evidence suggesting that the skeletal benefits continue once the treatment is discontinued. Possible complications of MHT include heart attacks, clots, strokes, dementia, and breast cancer. The most suitable candidates for MHT are women who have recently entered menopause, are experiencing menopausal symptoms, and are below 60 years of age with a minimal baseline risk of adverse events. The treatment is available to those who meet these criteria. For women undergoing premature menopause, MHT can be considered as a means to protect bone health, especially if initiated before menopause or if accelerated bone loss is documented soon after menopause. Such decisions should be made after evaluating individual risk factors and benefits.

Menopause-Biology, consequences, supportive care, and therapeutic options

Menopause is the cessation of ovarian function, with loss of reproductive hormone production and irreversible loss of fertility. It is a natural part of reproductive aging. The physiology of the menopause is complex and incompletely understood. Globally, menopause occurs around the age of 49 years, with geographic and ethnic variation. The hormonal changes of the menopause transition may result in both symptoms and long-term systemic effects, predominantly adverse effects on cardiometabolic and musculoskeletal health. The most effective treatment for bothersome menopausal symptoms is evidence-based, menopausal hormone therapy (MHT), which reduces bone loss and may have cardiometabolic benefits. Evidence-based non-hormonal interventions are also available for symptom relief. Treatment should be individualized with shared decision-making. Most MHT regimens are not regulator approved for perimenopausal women. Studies that include perimenopausal women are needed to determine the efficacy and safety of treatment options. Further research is crucial to improve menopause care, along with research to guide policy and clinical practice.

Role of Alternate Therapies to Improve the Quality of Life in Menopausal Women: A Systematic Review

Middle aged women in majority undergoing menopausal symptoms are unaware of the physiological changes happening in their body, necessary lifestyle changes and alternate therapies to overcome the symptoms. All major electronic sources of relevant information were systematically searched and collected data were pooled under specific subheadings. From the reviewed papers, the awareness on symptoms and related complications of menopause in the middle aged women were consolidated. Studies helped to identify alternative therapies replacing or in parallel with the Hormone Replacement Therapy to overcome the menopausal symptoms. Reduced oestrogen and progesterone level causes physiological, psychological, and genitourinary symptoms. Prolonged consequences cause libido, osteoporosis, and cardio vascular diseases. Hypo-estrogenic status is well managed with alternative therapies including dietary intervention, acupuncture, aromatherapy, exercise, and yoga. Dietary interventions involving foods like Fennel, Soy, Black Cohash, St. John Wort, Red Clover and Date Pollen were found to be managing vasomotor symptoms and sexual dysfunction. Non-Hormonal and Non-Pharmacological impact behind acupuncture treatment was well accepted. Various studies proved inhaling and massaging with Lavender, Neroli oil, Fennel, Rose, and Geranium essential oils balance cortisol hormone and reduce stress and anxiety. Impact of yoga therapy on neurohormonal pathways reduce both psychological and physiological symptoms. Reviews summarizes various symptoms and complications during menopausal transition and alternate ways of better management with dietary intervention, yoga, exercise, aromatherapy, and acupuncture to improve the quality of menopausal women's life.

Effects of Exercise Intensity on Cardiometabolic Parameters of Ovariectomized Obese Mice

The aim of this study was to compare the effects of continuous-moderate vs. high-intensity interval aerobic training on cardiovascular and metabolic parameters in ovariectomized high-fat-fed mice. C57BL/6 female ovariectomized were divided into four groups (n=8): low-fat-fed sedentary (SLF); high-fat-fed sedentary (SHF); high-fat-fed moderate-intensity continuous trained (MICT-HF); and high-fat-fed high-intensity interval aerobic trained (HIIT-HF). The high-fat diet lasted 10 weeks. Ovariectomy was performed in the fourth week. The exercise training was carried out in the last four weeks of protocol. Fasting glycemia, oral glucose tolerance, arterial pressure, baroreflex sensitivity, and cardiovascular autonomic modulation were evaluated. Moderate-intensity continuous training prevented the increase in arterial pressure and promoted a reduction in HR at rest, associated with an improvement in the sympathovagal balance in MICT-HF vs. SHF. The high-intensity interval training reduced blood glucose and glucose intolerance in HIIT-HF vs. SHF and MICT-HF. In addition, it improved sympathovagal balance in HIIT-HF vs. SHF. Moderate-intensity continuous training was more effective in promoting cardiovascular benefits, while high-intensity interval training was more effective in promoting metabolic benefits.

The Effect of High-Intensity Interval Training Type on Body Fat Percentage, Fat and Fat-Free Mass: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

This systematic review and meta-analysis of randomized controlled trials (RCTs) compared body compositional changes, including fat mass (FM), body fat percentage (BF%), and fat-free mass (FFM), between different types of high-intensity interval training (HIIT) (cycling vs. overground running vs. treadmill running) as well as to a control (i.e., no exercise) condition. Meta-analyses were carried out using a random-effects model. The I2 index was used to assess the heterogeneity of RCTs. Thirty-six RCTs lasting between 3 to 15 weeks were included in the current systematic review and meta-analysis. RCTs that examined the effect of HIIT type on FM, BF%, and FFM were sourced from online databases including PubMed, Scopus, Web of Science, and Google Scholar up to 21 June 2022. HIIT (all modalities combined) induced a significant reduction in FM (weighted mean difference [WMD]: −1.86 kg, 95% CI: −2.55 to −1.18, p = 0.001) despite a medium between-study heterogeneity (I2 = 63.3, p = 0.001). Subgroup analyses revealed cycling and overground running reduced FM (WMD: −1.72 kg, 95% CI: −2.41 to −1.30, p = 0.001 and WMD: −4.25 kg, 95% CI: −5.90 to −2.61, p = 0.001, respectively); however, there was no change with treadmill running (WMD: −1.10 kg, 95% CI: −2.82 to 0.62, p = 0.210). There was a significant reduction in BF% with HIIT (all modalities combined) compared to control (WMD: −1.53%, 95% CI: −2.13, −0.92, p = 0.001). All forms of HIIT also decreased BF%; however, overground running induced the largest overall effect (WMD: −2.80%, 95% CI: −3.89 to −1.71, p = 0.001). All types of HIIT combined also induced an overall significant improvement in FFM (WMD: 0.51 kg, 95% CI: 0.06 to 0.95, p = 0.025); however, only cycling interventions resulted in a significant increase in FFM compared to other exercise modalities (WMD: 0.63 kg, 95% CI: 0.17 to 1.09, p = 0.007). Additional subgroup analyses suggest that training for more than 8 weeks, at least 3 sessions per week, with work intervals less than 60 s duration and separated by ≤90 s active recovery are more effective for eliciting favorable body composition changes. Results from this meta-analysis demonstrate favorable body composition outcomes following HIIT (all modalities combined) with overall reductions in BF% and FM and improved FFM observed. Overall, cycling-based HIIT may confer the greatest effects on body composition due to its ability to reduce BF% and FM while increasing FFM.

Treating menopause - MHT and beyond

Every woman who lives past midlife will experience menopause, which, by definition, is complete cessation of ovarian function. This process might occur spontaneously (natural menopause) or be iatrogenic (secondary menopause), and can be further classified as 'early' if it occurs before the age of 45 years and 'premature' if it occurs before the age of 40 years. Globally, the mean age of natural menopause is 48.8 years, with remarkably little geographic variation. A woman's age at menopause influences health outcomes in later life. Early menopause is associated with a reduced risk of breast cancer, but increased risks of premature osteoporosis, cardiovascular disease and premature death. The cardinal symptoms of menopause, and adverse health sequelae, are due to loss of ovarian oestrogen production. Consequently, menopausal hormone therapy (MHT) that includes oestrogen or an oestrogenic compound ameliorates menopausal symptoms, while preventing menopause-associated bone loss and cardiometabolic changes. Importantly, comprehensive care of postmenopausal women involves lifestyle optimization (attention to nutrition and physical activity, reducing alcohol consumption and not smoking) and treating other established chronic disease risk factors. This Review offers a commentary specifically on the contemporary use of MHT and novel pharmaceutical alternatives to manage menopausal symptoms.

Menopause: a cardiometabolic transition

Menopause is often a turning point for women's health worldwide. Increasing knowledge from experimental data and clinical studies indicates that cardiometabolic changes can manifest at the menopausal transition, superimposing the effect of ageing onto the risk of cardiovascular disease. The menopausal transition is associated with an increase in fat mass (predominantly in the truncal region), an increase in insulin resistance, dyslipidaemia, and endothelial dysfunction. Exposure to endogenous oestrogen during the reproductive years provides women with protection against cardiovascular disease, which is lost around 10 years after the onset of menopause. In particular, women with vasomotor symptoms during menopause seem to have an unfavourable cardiometabolic profile. Early management of the traditional risk factors of cardiovascular disease (ie, hypertension, obesity, diabetes, dyslipidaemia, and smoking) is essential; however, it is important to recognise in the reproductive history the female-specific conditions (ie, gestational hypertension or diabetes, premature ovarian insufficiency, some gynaecological diseases such as functional hypothalamic amenorrhoea, and probably others) that could enhance the risk of cardiovascular disease during and after the menopausal transition. In this Review, the first of a Series of two papers, we provide an overview of the literature for understanding cardiometabolic changes and the management of women at midlife (40-65 years) who are at higher risk, focusing on the identification of factors that can predict the occurrence of cardiovascular disease. We also summarise evidence about preventive non-hormonal strategies in the context of cardiometabolic health.

Physiological Responses to Low-Volume Interval Training in Women

Interval training is a form of exercise that involves intermittent bouts of relatively intense effort interspersed with periods of rest or lower-intensity exercise for recovery. Low-volume high-intensity interval training (HIIT) and sprint interval training (SIT) induce physiological and health-related adaptations comparable to traditional moderate-intensity continuous training (MICT) in healthy adults and those with chronic disease despite a lower time commitment. However, most studies within the field have been conducted in men, with a relatively limited number of studies conducted in women cohorts across the lifespan. This review summarizes our understanding of physiological responses to low-volume interval training in women, including those with overweight/obesity or type 2 diabetes, with a focus on cardiorespiratory fitness, glycemic control, and skeletal muscle mitochondrial content. We also describe emerging evidence demonstrating similarities and differences in the adaptive response between women and men. Collectively, HIIT and SIT have consistently been demonstrated to improve cardiorespiratory fitness in women, and most sex-based comparisons demonstrate similar improvements in men and women. However, research examining insulin sensitivity and skeletal muscle mitochondrial responses to HIIT and SIT in women is limited and conflicting, with some evidence of blunted improvements in women relative to men. There is a need for additional research that examines physiological adaptations to low-volume interval training in women across the lifespan, including studies that directly compare responses to MICT, evaluate potential mechanisms, and/or assess the influence of sex on the adaptive response. Future work in this area will strengthen the evidence-base for physical activity recommendations in women.

The effects of low-intensity exercise on cardiac glycogenesis and glycolysis in male and ovariectomized female rats on a fructose-rich diet

We previously reported that low-intensity exercise prevented cardiac insulin resistance induced by a fructose-rich diet (FRD). To examine whether low-intensity exercise could prevent the disturbances of key molecules of cardiac glucose metabolism induced by FRD in male and ovariectomized (ovx) female rats, animals were exposed to 10% fructose solution (SF) or underwent both fructose diet and exercise (EF). Exercise prevented a decrease in cardiac GSK-3β phosphorylation induced by FRD in males (p < .001 vs. SF). It also prevented a decrease in PFK-2 phosphorylation in ovx females (p < .001 vs. SF) and increased the expression of PFK-2 in males (p < .05 vs. control). Exercise did not prevent a decrease in plasma membrane GLUT1 and GLUT4 levels in ovx females on FRD. The only effect of exercise on glucose transporters that could be indicated as beneficial is an augmented GLUT4 protein expression in males (p < .05 vs. control). Obtained results suggest that low-intensity exercise prevents harmful effects of FRD towards cardiac glycogenesis in males and glycolysis in ovx females. PRACTICAL APPLICATIONS: Low-intensity exercise, equivalent to brisk walking, was able to prevent disturbances in cardiac glycolysis regulation in ovx female and the glycogen synthesis pathway in male rats. In terms of human health, although molecular mechanisms of beneficial effects of exercise on cardiac glucose metabolism vary between genders, low-intensity running may be a useful non-pharmacological approach in the prevention of cardiac metabolic disorders in both men and postmenopausal women.

Resistance Band Exercise Training Prevents the Progression of Metabolic Syndrome in Obese Postmenopausal Women

Metabolic syndrome (MetS) is classified as a combination of risk factors for cardiovascular disease (CVD), and postmenopausal women are specifically at an increased risk for MetS, in part due to the hormonal and metabolic changes that occur at the menopause transition. It is crucial to combat the components of MetS with appropriate lifestyle interventions in this population, such as exercise. This study aimed to examine the effects of a resistance band exercise training program in obese postmenopausal women with MetS. A total 35 postmenopausal women were randomly assigned to either a control group (CON, n = 17) or a resistance band exercise training group (EX, n = 18). Participants in the EX group trained 3days/week. Levels of blood glucose, insulin, homeostatic model of insulin resistance (HOMA-IR), blood lipid profile, anthropometrics, and blood pressure (BP) were measured at baseline and after the exercise intervention. There were significant group by time interactions (p < 0.05) for blood glucose (Δ-4.5 mg/dl), insulin (Δ -1.3 μU/ml), HOMA-IR (Δ -0.6), triglycerides (Δ -9.4 mg/dl), low-density lipoprotein cholesterol(Δ -10.8 mg/dl), systolic BP(Δ -3.4 mmHg), body fat percentage (Δ -3.0 %), and waist circumference (Δ -3.4 cm), which significantly decreased (p < 0.05), and lean body mass (Δ 0.7 kg) and high-density lipoprotein cholesterol (Δ 5.1 mg/dl), which significantly increased (p < 0.05) after EX compared to no change in CON. The present study indicates that resistance band exercise training may be an effective therapeutic intervention to combat the components of MetS in this population, potentially reducing the risk for the development of CVD.

Menopausal transition does not influence skeletal muscle capillary growth in response to cycle training in women

The influence of the menopausal transition, with a consequent loss of estrogen, on capillary growth in response to exercise training remains unknown. In the present study, we evaluated the effect of a period of intense endurance training on skeletal muscle angiogenesis in late premenopausal and recent postmenopausal women with an age difference of <4 yr. Skeletal muscle biopsies were obtained from the thigh muscle before and after 12 wk of intense aerobic cycle training and analyzed for capillarization, fiber-type distribution, and content of vascular endothelial growth factor (VEGF). At baseline, there was no difference in capillary per fiber ratio (C:F; 1.41 ± 0.22 vs. 1.40 ± 0.30), capillary density (CD; 305 ± 61 vs. 336 ± 52 mm²), muscle fiber area (MFA; 4,889 ± 1,868 vs. 4,195 ± 749), or distribution of muscle fiber type I (47.3% ± 10.1% vs. 49.3% ± 15.1%), between the pre- and postmenopausal women, respectively. There was a main effect of training on the C:F ratio (+9.2% and +12.1%, for the pre- and postmenopausal women, respectively) and the CD (+6.9% and +8.9%, for the pre- and postmenopausal women, respectively). MFA and fiber-type distribution were unaltered by training. Skeletal muscle VEGF protein content was similar between groups at baseline, and there was a main effect of training (+21.1% and +27.2%, for the pre- and postmenopausal women, respectively). In conclusion, the loss of estrogen per se at menopause does not influence the capillary growth response to intense aerobic exercise training.NEW & NOTEWORTHY We evaluated the effect of 12 wk of intense aerobic exercise training on skeletal muscle angiogenesis in late pre- and recent postmenopausal women, with <4 yr of age difference. There was a main effect of training on capillary per fiber ratio, capillary density, and muscle VEGF protein content, with no difference between groups. It is concluded that the loss of estrogen per se at menopause does not influence the capillary growth response to intense aerobic training.

Effects of High-Intensity Exercise Training on Adipose Tissue Mass, Glucose Uptake and Protein Content in Pre- and Post-menopausal Women

The menopausal transition is accompanied by changes in adipose tissue storage, leading to an android body composition associated with increased risk of type 2 diabetes and cardiovascular disease in post-menopausal women. Estrogens probably affect local adipose tissue depots differently. We investigated how menopausal status and exercise training influence adipose tissue mass, adipose tissue insulin sensitivity and adipose tissue proteins associated with lipogenesis/lipolysis and mitochondrial function. Healthy, normal-weight pre- (n = 21) and post-menopausal (n = 20) women participated in high-intensity exercise training three times per week for 12 weeks. Adipose tissue distribution was determined by dual-energy x-ray absorptiometry and magnetic resonance imaging. Adipose tissue glucose uptake was assessed by positron emission tomography/computed tomography (PET/CT) by the glucose analog [18F]fluorodeoxyglucose ([18F]FDG) during continuous insulin infusion (40 mU·m⁻²·min⁻¹). Protein content associated with insulin signaling, lipogenesis/lipolysis, and mitochondrial function were determined by western blotting in abdominal and femoral white adipose tissue biopsies. The mean age difference between the pre- and the post-menopausal women was 4.5 years. Exercise training reduced subcutaneous (~4%) and visceral (~6%) adipose tissue masses similarly in pre- and post-menopausal women. Insulin-stimulated glucose uptake, assessed by [18F]FDG-uptake during PET/CT, was similar in pre- and post-menopausal women in abdominal, gluteal, and femoral adipose tissue depots, despite skeletal muscle insulin resistance in post- compared to pre-menopausal women in the same cohort. Insulin-stimulated glucose uptake in adipose tissue depots was not changed after 3 months of high-intensity exercise training, but insulin sensitivity was higher in visceral compared to subcutaneous adipose tissue depots (~139%). Post-menopausal women exhibited increased hexokinase and adipose triglyceride lipase content in subcutaneous abdominal adipose tissue. Physical activity in the early post-menopausal years reduces abdominal obesity, but insulin sensitivity of adipose tissue seems unaffected by both menopausal status and physical activity.

Mechanisms Underlying Absent Training-Induced Improvement in Insulin Action in Lean, Hyperandrogenic Women With Polycystic Ovary Syndrome

Women with polycystic ovary syndrome (PCOS) have been shown to be less insulin sensitive compared with control (CON) women, independent of BMI. Training is associated with molecular adaptations in skeletal muscle, improving glucose uptake and metabolism in both healthy individuals and patients with type 2 diabetes. In the current study, lean hyperandrogenic women with PCOS (n = 9) and healthy CON women (n = 9) completed 14 weeks of controlled and supervised exercise training. In CON, the training intervention increased whole-body insulin action by 26% and insulin-stimulated leg glucose uptake by 53% together with increased insulin-stimulated leg blood flow and a more oxidative muscle fiber type distribution. In PCOS, no such changes were found, despite similar training intensity and improvements in VO_2max In skeletal muscle of CON but not PCOS, training increased GLUT4 and HKII mRNA and protein expressions. These data suggest that the impaired increase in whole-body insulin action in women with PCOS with training is caused by an impaired ability to upregulate key glucose-handling proteins for insulin-stimulated glucose uptake in skeletal muscle and insulin-stimulated leg blood flow. Still, other important benefits of exercise training appeared in women with PCOS, including an improvement of the hyperandrogenic state.

The Effect of Low-Volume High-Intensity Interval Training on Body Composition and Cardiorespiratory Fitness: A Systematic Review and Meta-Analysis

BACKGROUND

Evidence for the efficacy of low-volume high-intensity interval training (HIIT) for the modulation of body composition is unclear.

OBJECTIVES

We examined the effect of low-volume HIIT versus a non-exercising control and moderate-intensity continuous training (MICT) on body composition and cardiorespiratory fitness in normal weight, overweight and obese adults. We evaluated the impact of low-volume HIIT (HIIT interventions where the total amount of exercise performed during training was ≤ 500 metabolic equivalent minutes per week [MET-min/week]) compared to a non-exercising control and MICT.

METHODS

A database search was conducted in PubMed (MEDLINE), EMBASE, CINAHL, Web of Science, SPORTDiscus and Scopus from the earliest record to June 2019 for studies (randomised controlled trials and non-randomised controlled trials) with exercise training interventions with a minimum 4-week duration. Meta-analyses were conducted for between-group (low-volume HIIT vs. non-exercising control and low-volume HIIT vs. MICT) comparisons for change in total body fat mass (kg), body fat percentage (%), lean body mass (kg) and cardiorespiratory fitness.

RESULTS

From 11,485 relevant records, 47 studies were included. No difference was found between low-volume HIIT and a non-exercising control on total body fat mass (kg) (effect size [ES]: - 0.129, 95% confidence interval [CI] - 0.468 to 0.210; p = 0.455), body fat (%) (ES: - 0.063, 95% CI - 0.383 to 0.257; p = 0.700) and lean body mass (kg) (ES: 0.050, 95% CI - 0.250 to 0.351; p = 0.744), or between low-volume HIIT and MICT on total body fat mass (kg) (ES: - 0.021, 95% CI - 0.272 to 0.231; p = 0.872), body fat (%) (ES: 0.005, 95% CI - 0.294 to 0.304; p = 0.974) and lean body mass (kg) (ES: 0.030, 95% CI - 0.167 to 0.266; p = 0.768). However, low-volume HIIT significantly improved cardiorespiratory fitness compared with a non-exercising control (p < 0.001) and MICT (p = 0.017).

CONCLUSION

These data suggest that low-volume HIIT is inefficient for the modulation of total body fat mass or total body fat percentage in comparison with a non-exercise control and MICT. A novel finding of our meta-analysis was that there appears to be no significant effect of low-volume HIIT on lean body mass when compared with a non-exercising control, and while most studies tended to favour improvement in lean body mass with low-volume HIIT versus MICT, this was not significant. However, despite its lower training volume, low-volume HIIT induces greater improvements in cardiorespiratory fitness than a non-exercising control and MICT in normal weight, overweight and obese adults. Low-volume HIIT, therefore, appears to be a time-efficient treatment for increasing fitness, but not for the improvement of body composition.

Inactivity and Skeletal Muscle Metabolism: A Vicious Cycle in Old Age

Aging is an inevitable and gradually progressive process affecting all organs and systems. The musculoskeletal system makes no exception, elderly exhibit an increased risk of sarcopenia (low muscle mass),dynapenia (declining muscle strength), and subsequent disability. Whereas in recent years the subject of skeletal muscle metabolic decline in the elderly has been gathering interest amongst researchers, as well as medical professionals, there are many challenges yet to be solved in order to counteract the effects of aging on muscle function efficiently. Noteworthy, it has been shown that aging individuals exhibit a decline in skeletal muscle metabolism, a phenomenon which may be linked to a number of predisposing (risk) factors such as telomere attrition, epigenetic changes, mitochondrial dysfunction, sedentary behavior (leading to body composition alterations), age-related low-grade systemic inflammation (inflammaging), hormonal imbalance, as well as a hypoproteic diet (unable to counterbalance the repercussions of the age-related increase in skeletal muscle catabolism). The present review aims to discuss the relationship between old age and muscle wasting in an effort to highlight the modifications in skeletal muscle metabolism associated with aging and physical activity.

Impact of Endurance and Resistance Training on Skeletal Muscle Glucose Metabolism in Older Adults

Aging is associated with insulin resistance and the development of type 2 diabetes. While this process is multifaceted, age-related changes to skeletal muscle are expected to contribute to impaired glucose metabolism. Some of these changes include sarcopenia, impaired insulin signaling, and imbalances in glucose utilization. Endurance and resistance exercise training have been endorsed as interventions to improve glucose tolerance and whole-body insulin sensitivity in the elderly. While both types of exercise generally increase insulin sensitivity in older adults, the metabolic pathways through which this occurs can differ and can be dependent on preexisting conditions including obesity and type 2 diabetes. In this review, we will first highlight age-related changes to skeletal muscle which can contribute to insulin resistance, followed by a comparison of endurance and resistance training adaptations to insulin-stimulated glucose metabolism in older adults.