Leg vascular and skeletal muscle mitochondrial adaptations to aerobic high-intensity exercise training are enhanced in the early postmenopausal phase

Unveiling the role of exercise in modulating plasma heat shock protein 27 levels: insights for exercise immunology and cardiovascular health

Cardiovascular disease is one of the leading causes of mortality worldwide, primarily driven by atherosclerosis, a chronic inflammatory condition contributing significantly to fatalities. Various biological determinants affecting cardiovascular health across different age and sex groups have been identified. In this context, recent attention has focused on the potential therapeutic and preventive role of increasing circulating levels of heat shock protein 27 (plasma HSP27) in combating atherosclerosis. Plasma HSP27 is recognized for its protective function in inflammatory atherogenesis, offering promising avenues for intervention and management strategies against this prevalent cardiovascular ailment. Exercise has emerged as a pivotal strategy in preventing and managing cardiovascular disease, with literature indicating an increase in plasma HSP27 levels post-exercise. However, there is limited understanding of the impact of exercise on the release of HSP27 into circulation. Clarifying these aspects is crucial for understanding the role of exercise in modulating plasma HSP27 levels and its potential implications for cardiovascular health across diverse populations. Therefore, this review aims to establish a more comprehensive understanding of the relationship between plasma HSP27 and exercise.

Sex differences in skeletal muscle metabolism in exercise and type 2 diabetes mellitus

This Review focuses on currently available literature describing sex differences in skeletal muscle metabolism in humans, as well as highlighting current research gaps within the field. These discussions serve as a call for action to address the current lack of sufficient sex-balanced studies in skeletal muscle research, and the resulting limitations in understanding sex-specific physiological and pathophysiological responses. Although the participation of women in studies has increased, parity between the sexes remains elusive, affecting the validity of conclusions drawn from studies with limited numbers of participants. Changes in skeletal muscle metabolism contribute to the development of metabolic disease (such as type 2 diabetes mellitus), and maintenance of skeletal muscle mass is a key component for health and the ability to maintain an independent life during ageing. Exercise is an important factor in maintaining skeletal muscle health and insulin sensitivity, and offers promise for both prevention and treatment of metabolic disease. With the increased realization of the promise of precision medicine comes the need to increase patient stratification and improve the understanding of responses in different populations. In this context, a better understanding of sex-dependent differences in skeletal muscle metabolism is essential.

Higher amounts of habitual physical activity changes the relationship between hot flashes and subclinical cardiovascular disease risk

The menopausal transition is associated with increased risk for cardiovascular disease (CVD). Hot flashes (HF), a cardinal symptom of menopause, have been associated with increased CVD risk, particularly in perimenopausal women. Flow-mediated dilation (FMD) is an indicator of endothelial function and a subclinical CVD risk factor. Lower FMD has been associated with more HF. As moderate to vigorous physical activity (MVPA) is recognized to reduce CVD risk, our goal was to determine whether higher levels of MVPA change the relationship between HF and FMD in perimenopausal women. Healthy perimenopausal women had HF measured objectively using sternal skin conductance for 24 h. MVPA was determined using 7 days of actigraphy. Endothelial function was measured via brachial artery FMD on the non-dominant arm. Pearson correlations and multiple regression analyses were used to evaluate relationships between variables. Simple slopes analysis was performed to understand how MVPA moderates the relationship between HF and FMD. Lower FMD tended to correlate with a higher objective HF rate, and this relationship was stronger for HF measured during waking hours. Controlling for age and BMI, HF and the interaction between HF and MVPA were significant predictors of FMD. Simple slope analysis showed a significant HF effect on FMD with lower (-1SD) MVPA, whereas there was no significant relationship between HF and FMD with higher (+1SD) MVPA. These results suggest that MVPA moderates the relationship between FMD and objective HFs in perimenopausal women.

Plasma volume variations in response to high intensity interval training in obese women: The influential role of menopausal status and age

OBJECTIVE

This study aims to explore the effects of high-intensity interval training (HIIT) on plasma volume (PV) variations in obese women, with a focus on understanding how menopausal status and age influence these changes.

METHODS

We enrolled fifty-nine obese women (perimenopausal and postmenopausal), aged approximately 56.6 years in a six-week HIIT program. Measurements of fitness, health, and PV were taken before and after the intervention. PV was assessed at two points during each session: at post-warm-up (PV1), and immediately post-training (PV2). These measurements were derived using hematocrit (Ht) and hemoglobin (Hb) values.

RESULTS

The intervention led to notable reductions in anthropometric measures and blood pressure (P < 0.01). For all women pre- and post-HIIT comparisons revealed significant differences in the extent of PV reduction at all two points (P < 0.01). Multiple linear regression analysis revealed that age was a significant contributor to the decreases in plasma volume (PV) observed both after warm-up and following the supramaximal cycling test - SCT (r = 0.44 and r = 0.57). On the other hand, menopause status was an independent predictor for PV decreases after warm-up (r = 0.33) as well after SCT (r = 0.38). Following HIIT, only menopause status accounted for 19 % of the variation in PV decreases after warm-up and 21 % of the variation in PV decreases after SCT.

CONCLUSIONS

The findings suggest that HIIT is effective in enhancing plasma volume among obese menopausal women, attenuating the age-related decline in PV.

Preworkout dietary nitrate magnifies training-induced benefits to physical function in late postmenopausal women: a randomized pilot study

To inform end points for future work, we explored the utility of preworkout (i.e., an acute dose before training) beetroot juice (BRJ) combined with exercise (BRJ + EX) to augment indices of physical function in postmenopausal women compared with exercise only (EX). A two-arm pilot study was used to compare 24 postmenopausal women following an 8-wk, circuit-based exercise intervention. Participants were randomized to BRJ + EX (n = 12) or EX (n = 12). BRJ + EX participants consumed 140 mL of BRJ 120-180 min (only) before training for 7 wk, then discontinued during the final week to mitigate carryover effects. Physical function indices were 6-min walk test (6MWT), estimated V̇o2peak, heart rate recovery (HRR), and maximal knee extensor power (Pmax). A treadmill task was used to measure V̇o2 on-kinetics wherein mean response time (MRT) coincided with the duration to reach 63% of steady-state V̇o2. Results showed greater changes (Δ) among BRJ + EX participants for 6MWT distance (40 ± 23 m vs. 8 ± 25 m; P = 0.003, d = 1.35), ΔV̇o2peak (1.5 ± 0.9 mL·kg-1·min-1 vs. 0.3 ± 1.0 mL·kg-1·min-1; P = 0.008, d = 1.20), and ΔHRR (-10 ± 6 beats/min vs. -1 ± 9 beats/min; P = 0.017, d = 1.05). Large and medium effect sizes favoring BRJ + EX were detected for ΔPmax (P = 0.07, d = 0.83) and ΔMRT (P = 0.257, d = 0.50), respectively. In postmenopausal women, BRJ + EX appears to magnify some adaptive benefits to physical function including aerobic capacity and recovery beyond that of training without BRJ. Investigation into contributing mechanisms is needed.NEW & NOTEWORTHY Though exercise training represents the principal strategy to combat age-related decline, the attendant effects of menopause weaken aspects of exercise adaptation compared with premenopausal women and age-matched men. Here we provide important initial evidence that preworkout (i.e., an acute dose before training) beetroot juice coupled with an 8-wk, circuit-based exercise training intervention may uniquely benefit late postmenopausal women by enhancing indices of physical function including aerobic capacity and recovery.

Exercise training alters skeletal muscle microvascular endothelial cell properties in recent postmenopausal females

The present study examined and compared the impact of exercise training on redox and molecular properties of human microvascular endothelial cells derived from skeletal muscle biopsies from sedentary recent (RPF, ≤ 5 years as postmenopausal) and late (LPF, ≥ 10 years as postmenopausal) postmenopausal females. Resting skeletal muscle biopsies were obtained before and after 8 weeks of intense aerobic exercise training for isolation of microvascular endothelial cells and determination of skeletal muscle angiogenic proteins and capillarisation. The microvascular endothelial cells were analysed for mitochondrial respiration and production of reactive oxygen species (ROS), glycolysis and proteins related to vascular function, redox balance and oestrogen receptors. Exercise training led to a reduced endothelial cell ROS formation (∼50%; P = 0.009 and P = 0.020 for intact and permeabilized cells (state 3), respectively) in RPF only, with no effect on endothelial mitochondrial capacity in either group. Basal endothelial cell lactate formation was higher (7%; P = 0.028), indicating increased glycolysis, after compared to before the exercise training period in RPF only. Baseline endothelial G protein-coupled oestrogen receptor (P = 0.028) and muscle capillarisation (P = 0.028) was lower in LPF than in RPF. Muscle vascular endothelial growth factor protein was higher (32%; P = 0.002) following exercise training in LPF only. Exercise training did not influence endothelial cell proliferation or skeletal muscle capillarisation in either group, but the CD31 level in the muscle tissue, indicating endothelial cell content, was higher (>50%; P < 0.05) in both groups. In conclusion, 8 weeks of intense aerobic exercise training reduces ROS formation and enhances glycolysis in microvascular endothelial cells from RPF but does not induce skeletal muscle angiogenesis. KEY POINTS: Late postmenopausal females have been reported to achieve limited vascular adaptations to exercise training. There is a paucity of data on the effect of exercise training on isolated skeletal muscle microvascular endothelial cells (MMECs). In this study the formation of reactive oxygen species in MMECs was reduced and glycolysis increased after 8 weeks of aerobic exercise training in recent but not late postmenopausal females. Late postmenopausal females had lower levels of G protein-coupled oestrogen receptor in MMECs and lower skeletal muscle capillary density at baseline. Eight weeks of intense exercise training altered MMEC properties but did not induce skeletal muscle angiogenesis in postmenopausal females.

Effects of aging and endurance exercise training on cardiorespiratory fitness and cardiac structure and function in healthy midlife and older women

Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality in women in developed societies. Unfavorable structural and functional adaptations within the heart and central blood vessels with sedentary aging in women can act as the substrate for the development of debilitating CVD conditions such as heart failure with preserved ejection fraction (HFpEF). The large decline in cardiorespiratory fitness, as indicated by maximal or peak oxygen uptake (V̇o2max and V̇o2peak, respectively), that occurs in women as they age significantly affects their health and chronic disease status, as well as the risk of cardiovascular and all-cause mortality. Midlife and older women who have performed structured endurance exercise training for several years or decades of their adult lives exhibit a V̇o2max and cardiac and vascular structure and function that are on par or even superior to much younger sedentary women. Therefore, regular endurance exercise training appears to be an effective preventative strategy for mitigating the adverse physiological cardiovascular adaptations associated with sedentary aging in women. Herein, we narratively describe the aging and short- and long-term endurance exercise training adaptations in V̇o2max, cardiac structure, and left ventricular systolic and diastolic function at rest and exercise in midlife and older women. The role of circulating estrogens on cardiac structure and function is described for consideration in the timing of exercise interventions to maximize beneficial adaptations. Current research gaps and potential areas for future investigation to advance our understanding in this critical knowledge area are highlighted.

The role of estrogen in female skeletal muscle aging: A systematic review

Aging is associated with a loss of skeletal muscle mass and function that negatively impacts the independence and quality of life of older individuals. Females demonstrate a distinct pattern of muscle aging compared to males, potentially due to menopause, when the production of endogenous sex hormones declines. This systematic review aims to investigate the current knowledge about the role of estrogen in female skeletal muscle aging. A systematic search of MEDLINE Complete, Global Health, Embase, PubMed, SPORTDiscus, and CINHAL was conducted. Studies were considered eligible if they compared a state of estrogen deficiency (e.g. postmenopausal females) or supplementation (e.g. estrogen therapy) to normal estrogen conditions (e.g. premenopausal females or no supplementation). Outcome variables of interest included measures of skeletal muscle mass, function, damage/repair, and energy metabolism. Quality assessment was completed with the relevant Johanna Briggs critical appraisal tool, and data were synthesized in a narrative manner. Thirty-two studies were included in the review. Compared to premenopausal women, postmenopausal women had reduced muscle mass and strength, but the effect of menopause on markers of muscle damage and expression of the genes involved in metabolic signaling pathways remains unclear. Some studies suggest a beneficial effect of estrogen therapy on muscle size and strength, but evidence is largely conflicting and inconclusive, potentially due to large variations in the reporting and status of exposure and outcomes. The findings from this review point toward a potential negative effect of estrogen deficiency on aging skeletal muscle, but further mechanistic evidence is needed to clarify its role.

Effect of Exercise Training on Blood Pressure in Healthy Postmenopausal Females: A Systematic Review with Meta-analysis

INTRODUCTION

The prevalence of hypertension is greater in postmenopausal females compared with males of similar age. Previous meta-analyses of normotensive and hypertensive adults have shown that aerobic exercise training reduces systolic blood pressure (SBP) and/or diastolic blood pressure (DBP). However, the effect of aerobic exercise training on blood pressure specifically within healthy postmenopausal females remains unclear. This systematic review with meta-analysis quantified the effect of aerobic exercise training on resting SBP and DBP in healthy postmenopausal females.

METHODS

The systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Review and Meta-analyses guidelines and was registered in PROSPERO (CRD42020198171). The literature search was done in MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, CINAHL Plus, and SPORTDiscus. Randomized controlled trials involving healthy postmenopausal females with normal or high normal blood pressure and undergoing ≥4 wk of aerobic exercise training were included. The total weighted mean change in SBP and DBP was compared between the exercise and the control interventions. A random-effects model was used to calculate the overall effect sizes of the weighted mean differences and the 95% confidence interval (CI).

RESULTS

Twelve studies were included in the meta-analysis (exercise interventions: n = 357, age = 60 ± 4 yr, baseline SBP/DBP = 128 ± 13/79 ± 8 mm Hg; control interventions: n = 330, age = 60 ± 4 yr, baseline SBP/DBP = 126 ± 11/77 ± 6 mm Hg). Compared with the change observed in response to the control interventions, exercise training significantly reduced SBP (-0.43 mm Hg, 95% CI = -0.78 to -0.09, P = 0.02) and DBP (-0.39 mm Hg, 95% CI = -0.73 to -0.05, P = 0.05).

CONCLUSIONS

Aerobic exercise training significantly reduces resting SBP and DBP in healthy postmenopausal females with normal or high normal blood pressure. However, this reduction is small and of uncertain clinical significance.

Pelvic floor muscle rehabilitation for genitourinary syndrome of menopause: why, how and when?

Genitourinary syndrome of menopause (GSM) is caused by chronic deprivation of estrogen and other sex steroids during the postmenopausal period, which leads to changes in the vulvovaginal tissues. These changes cause bothersome symptoms, such as vaginal dryness, pruritus, dyspareunia, increased daytime urinary frequency, urgency and urinary incontinence, which have considerable negative effects on women's quality of life and sexual function. Recent studies have investigated a novel treatment approach for GSM. Pelvic floor muscle (PFM) rehabilitation, a low-cost conservative management with no side-effects, has been studied alone or in combination with other treatment modalities to reduce the signs and symptoms of GSM. The aim of this article is to discuss why PFM rehabilitation could be useful for women with GSM, how it may help improve signs and symptoms of GSM and when this treatment should be recommended.

Exercised accelerated the production of muscle-derived kynurenic acid in skeletal muscle and alleviated the postmenopausal osteoporosis through the Gpr35/NFκB p65 pathway

Background

Reduced serum estrogen levels in postmenopausal patients not only aggravate bone loss but also impact myokine secretion. Emerging evidence has revealed the importance of myokines in bone metabolism, and exercise can interfere with the secretion of myokines. However, few studies have explored the impact of exercise on myokine secretion in the postmenopausal osteoporosis (PMOP) process.

Methods

Ten-weeks-old C57B/L6 female mice were used for constructing the postmenopausal osteoporosis model. The expression levels of kynurenine aminotransferases (Kats) were detected by RT-PCR and Western Blot. The concentration of serum kynurenic acid (Kyna) was detected by HPLC-MS. Micro-CT analysis was used for determine the changes of bone mineral density and the microstructure. The primary osteoblast and osteoclast were isolated from mice to determine the effect and mechanism of Kyna on the bone formation and resorption.

Results

In our research, we found a lower serum level of muscle-derived kynurenic acid (Kyna) in PMOP model mice, accompanied by a decreased level of kynurenine aminotransferases (Kats) in the gastrocnemius muscle. Moreover, treadmill-running exercise upregulated the muscle levels of KATs and increased the serum concentration of Kyna, which was positively correlated with the alleviation of bone loss. Furthermore, we found that exogenous Kyna treatment alleviated bone mineral loss and microstructure destruction in PMOP mice by inhibiting osteoclast maturation and increasing osteoblast viability. Mechanistically, we observed that Kyna reduced the NFκB p65 phosphorylation level by activating the Gpr35 receptor, which inhibited NFATc1 expression in osteoclasts and upregulated Runx2 expression in osteoblasts.

Conclusion

Our results revealed that the muscle levels of Kats and serum level of Kyna were negatively correlated with the severity of PMOP. Exercise intervention and exogenous Kyna treatment alleviated the impairment of bone microstructure through the Gpr35 receptor, paving the way for a novel therapeutic intervention in PMOP.

The Translational potential of this article

This study provides evidences that Kyna could increase the osteoblastgenesis and inhibit the osteoclastgenesis, which could be a novel therapeutic approach for osteoporosis treatment.

Short-Term Supplementation With Fermented Red Clover Extract Reduces Vascular Inflammation in Early Post-menopausal Women

The decline in estrogen at menopause poses a critical challenge to cardiovascular and metabolic health. Recently, a growing interest in the role of phytoestrogens, with a particular focus on isoflavones, has emerged as they can bind to estrogen receptors and may mimic the roles of endogenous estrogen. Fermented red clover extract (RC) contains isoflavones with superior bioavailability compared to non-fermented isoflavones, however little is known regarding the impact of isoflavones on cardiovascular and metabolic health. We assessed markers of vascular health in plasma and skeletal muscle samples obtained from healthy but sedentary early post-menopausal women (n = 10; 54 ± 4 years) following 2 weeks of twice daily treatment with placebo (PLA) or RC (60 mg isoflavones per day). The two interventions were administered using a randomized, double-blind, crossover design with a two-week washout period. Plasma samples were utilized for assessment of markers of vascular inflammation. There was a statistically significant reduction (~5.4%) in vascular cell adhesion molecule 1 (VCAM-1) following 2 weeks of RC supplementation compared to PLA (p = 0.03). In contrast, there was no effect of RC supplementation compared to PLA on skeletal muscle estrogen receptor content and enzymes related to vascular function, and angiogenesis. Supplementation with RC reduces vascular inflammation in early post-menopausal women and future studies should address the long-term impact of daily supplementation with RC after menopause.

Linking Physical Activity to Breast Cancer via Sex Hormones, Part 1: The Effect of Physical Activity on Sex Steroid Hormones

The effect of physical activity on breast cancer risk may be partly mediated by sex steroid hormones. This review synthesized and appraised the evidence for an effect of physical activity on sex steroid hormones. Systematic searches were performed using MEDLINE (Ovid), EMBASE (Ovid), and SPORTDiscus to identify experimental studies and prospective cohort studies that examined physical activity and estrogens, progestins, and/or androgens, as well as sex hormone binding globulin (SHBG) and glucocorticoids in pre- and postmenopausal women. Meta-analyses were performed to generate effect estimates. Risk of bias was assessed, and the GRADE system was used to appraise quality of the evidence. Twenty-eight randomized controlled trials (RCT), 81 nonrandomized interventions, and six observational studies were included. Estrogens, progesterone, and androgens mostly decreased, and SHBG increased, in response to physical activity. Effect sizes were small, and evidence quality was graded moderate or high for each outcome. Reductions in select sex steroid hormones following exercise supports the biological plausibility of the first part of the physical activity-sex hormone-breast cancer pathway. The confirmed effect of physical activity on decreasing circulating sex steroid hormones supports its causal role in preventing breast cancer.See related reviews by Lynch et al., p. 11 and Drummond et al., p. 28.

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.

Aerobic High-Intensity Exercise Training Improves Cardiovascular Health in Older Post-menopausal Women

The aim of this study was to determine the effect of a period of aerobic high intensity training on central- and peripheral cardiovascular parameters in older post-menopausal women. Eleven healthy post-menopausal (>10 years after menopause) women (mean age: 64 years; BMI: 25.3 kg m⁻²) completed an 8-week period of supervised, high intensity cycle training, with sessions conducted three times per week. Before and after the training period maximal oxygen uptake, body composition, popliteal artery flow mediated dilation, exercise hyperemia, arterial blood pressure, and plasma lipids were assessed. In addition, levels of estrogen related receptor α (ERRα) and vasodilator enzymes were determined in muscle biopsy samples. Training induced an 18% increase (P < 0.001) in maximal oxygen uptake. Plasma High-density lipoprotein (HDL) was higher (P < 0.05) after than before the training period. Fat mass was reduced (4.9%; P < 0.01), whereas lean body mass was unaltered. Mean arterial blood pressure was unchanged (91 vs. 88 mmHg; P = 0.058) with training. Training did not induce a change in popliteal flow mediated dilation. Exercise hyperemia at submaximal exercise was lower (P < 0.01; 11 and 4.6% at 10 and 16 W, respectively) after compared to before training. Muscle ERRα (~1.7-fold; P < 0.01) and eNOS (~1.4-fold; P < 0.05) were higher after the training intervention. The current study demonstrates that, in older post-menopausal women, a period of aerobic high intensity training effectively increases maximal oxygen uptake and improves the cardiovascular health profile, without a parallel improvement in conduit artery function.

Does Exercise Influence the Susceptibility to Arterial Thrombosis? An Integrative Perspective

Arterial thrombosis is the primary cause of death worldwide, with the most important risk factors being smoking, unhealthy diet, and physical inactivity. However, although there are clear indications in the literature of beneficial effects of physical activity in lowering the risk of cardiovascular events, exercise can be considered a double-edged sword in that physical exertion can induce an immediate pro-thrombotic environment. Epidemiological studies show an increased risk of cardiovascular events after acute exercise, a risk, which appear to be particularly apparent in individuals with lifestyle-related disease. Factors that cause the increased susceptibility to arterial thrombosis with exercise are both chemical and mechanical in nature and include circulating catecholamines and vascular shear stress. Exercise intensity plays a marked role on such parameters, and evidence in the literature accordingly points at a greater susceptibility to thrombus formation at high compared to light and moderate intensity exercise. Of importance is, however, that the susceptibility to arterial thrombosis appears to be lower in exercise-conditioned individuals compared to sedentary individuals. There is currently limited data on the role of acute and chronic exercise on the susceptibility to arterial thrombosis, and many studies include incomplete assessments of thrombogenic clotting profile. Thus, further studies on the role of exercise, involving valid biomarkers, are clearly warranted.

Hypertension is associated with blunted NO-mediated leg vasodilator responsiveness that is reversed by high-intensity training in postmenopausal women

The menopausal transition is associated with increased prevalence of hypertension, and in time, postmenopausal women (PMW) will exhibit a cardiovascular disease risk score similar to male counterparts. Hypertension is associated with vascular dysfunction, but whether hypertensive (HYP) PMW have blunted nitric oxide (NO)-mediated leg vasodilator responsiveness and whether this is reversible by high-intensity training (HIT) is unknown. To address these questions, we examined the leg vascular conductance (LVC) in response to femoral infusion of acetylcholine (ACh) and sodium nitroprusside (SNP) and skeletal muscle markers of oxidative stress and NO bioavailability before and after HIT in PMW [12.9 ± 6.0 (means ± SD) years since last menstrual cycle]. We hypothesized that ACh- and SNP-induced LVC responsiveness was reduced in hypertensive compared with normotensive (NORM) PMW and that 10 wk of HIT would reverse the blunted LVC response and decrease blood pressure (BP). Nine hypertensive (HYP (clinical systolic/diastolic BP, 149 ± 11/91 ± 83 mmHg) and eight normotensive (NORM (122 ± 13/75 ± 8 mmHg) PMW completed 10 wk of biweekly small-sided floorball training (4-5 × 3-5 min interspersed by 1-3-min rest periods). Before training, the SNP-induced change in LVC was lower (P < 0.05) in HYP compared with in NORM. With training, the ACh- and SNP-induced change in LVC at maximal infusion rates, i.e., 100 and 6 µg·min^-1·kg leg mass^-1, respectively, improved (P < 0.05) in HYP only. Furthermore, training decreased (P < 0.05) clinical systolic/diastolic BP (-15 ± 11/-9 ± 7 mmHg) in HYP and systolic BP (-10 ± 9 mmHg) in NORM. Thus, the SNP-mediated LVC responsiveness was blunted in HYP PMW and reversed by a period of HIT that was associated with a marked decrease in clinical BP.

Increased prostacyclin formation after high-intensity interval training in late postmenopausal women

PURPOSE

Aging impairs vascular function in women, with the largest detrimental effects occurring during the menopausal transition. Deficiency in the nitric oxide system has been suggested to be responsible for impairment in vascular function with aging, but recent observations suggest that the prostacyclin system, acting in redundancy with the nitric oxide system, may be of importance too. Improvement in vascular function is a hallmark of exercise training and we hypothesize that leg vascular function is improved by exercise training in late postmenopausal women, and that the underlying mechanism is increased endothelial formation of prostacyclin and responsiveness to prostacyclin by the vascular smooth muscle cells.

METHOD

Femoral-arterial infusion of acetylcholine and epoprostenol was used to assess vascular function and prostacyclin release in ten late postmenopausal women (62 ± 7 years) before and after 10 weeks of high-intensity interval training (floorball conducted as small-sided games).

RESULT

The training intervention increased fitness level (V̇O2max) by 7 ± 7% and reduced systolic and diastolic blood pressure by 10 ± 10 and 5 ± 6 mmHg, respectively. Leg vascular responsiveness to during acetylcholine and epoprostenol infusion was unchanged with training, whereas the release of prostacyclin during acetylcholine infusion increased by 125%.

CONCLUSIONS

In late postmenopausal women, vascular function assessed by femoral-arterial infusion of acetylcholine was not improved after 10 weeks of floorball training, but acetylcholine-induced prostacyclin formation and blood pressure were substantially improved. It is possible that a longer training period could lead to improvements in vascular function and that the observed increase in prostacyclin formation is one of the initial underlying changes.

Increased oxygen extraction and mitochondrial protein expression after small muscle mass endurance training

When exercising with a small muscle mass, the mass-specific O₂ delivery exceeds the muscle oxidative capacity resulting in a lower O₂ extraction compared with whole-body exercise. We elevated the muscle oxidative capacity and tested its impact on O₂ extraction during small muscle mass exercise. Nine individuals conducted six weeks of one-legged knee extension (1L-KE) endurance training. After training, the trained leg (TL) displayed 45% higher citrate synthase and COX-IV protein content in vastus lateralis and 15%-22% higher pulmonary oxygen uptake ( V ˙ O 2 peak ) and peak power output ( W ˙ peak ) during 1L-KE than the control leg (CON; all P < .05). Leg O₂ extraction (catheters) and blood flow (ultrasound Doppler) were measured while both legs exercised simultaneously during 2L-KE at the same submaximal power outputs (real-time feedback-controlled). TL displayed higher O₂ extraction than CON (main effect: 1.7 ± 1.6% points; P = .010; 40%-83% of W ˙ peak ) with the largest between-leg difference at 83% of W ˙ peak (O₂ extraction: 3.2 ± 2.2% points; arteriovenous O₂ difference: 7.1 ± 4.8 mL· L^-1 ; P < .001). At 83% of W ˙ peak , muscle O₂ conductance (D_M O₂ ; Fick law of diffusion) and the equilibration index Y were higher in TL (P < .01), indicating reduced diffusion limitations. The between-leg difference in O₂ extraction correlated with the between-leg ratio of citrate synthase and COX-IV (r = .72-.73; P = .03), but not with the difference in the capillary-to-fiber ratio (P = .965). In conclusion, endurance training improves O₂ extraction during small muscle mass exercise by elevating the muscle oxidative capacity and the recruitment of D_M O_2, especially evident during high-intensity exercise exploiting a larger fraction of the muscle oxidative capacity.

The effect of lifelong endurance exercise on cardiovascular structure and exercise function in women

KEY POINTS

The beneficial effects of sustained or lifelong (>25 years) endurance exercise on cardiovascular structure and exercise function have been largely established in men. The current findings indicate that committed (≥4 weekly exercise sessions) lifelong exercise results in substantial benefits in exercise capacity ( V ̇ O 2 max ), cardiovascular function at submaximal and maximal exercise, left ventricular mass and compliance, and blood volume compared to similarly aged or even younger (middle-age) untrained women. Endurance exercise training should be considered a key strategy to prevent cardiovascular disease with ageing in women as well as men.

ABSTRACT

This study was a retrospective, cross-sectional analysis of exercise performance and left ventricular (LV) morphology in 70 women to examine whether women who have performed regular, lifelong endurance exercise acquire the same beneficial adaptations in cardiovascular structure and function and exercise performance that have been reported previously in men. Three groups of women were examined: (1) 35 older (>60 years) untrained women (older untrained, OU), (2) 13 older women who had consistently performed four or more endurance exercise sessions weekly for at least 25 years (older trained, OT), and (3) 22 middle-aged (range 35-59 years) untrained women (middle-aged untrained, MU) as a reference control for the appropriate age-related changes. Oxygen uptake ( V ̇ O 2 ) and cardiovascular function (cardiac output ( Q ̇ ); stroke volume (SV) acetylene rebreathing) were examined at rest, steady-state submaximal exercise and maximal exercise (maximal oxygen uptake, V ̇ O 2 max ). Blood volume (CO rebreathing) and LV mass (cardiac magnetic resonance imaging), plus invasive measures of static and dynamic chamber compliance were also examined. V ̇ O 2 max (p < 0.001) and maximal exercise Q ̇ and SV were larger in older trained women compared to the two untrained groups (∼17% and ∼27% for Q ̇ and SV, respectively, versus MU; ∼40% and ∼38% versus OU, all p < 0.001). Blood volume (mL kg^-1 ) and LV mass index (g m^-2 ) were larger in OT versus OU (∼11% and ∼16%, respectively, both P ≤ 0.015) Static LV chamber compliance was greater in OT compared to both untrained groups (median (25-75%): MU: 0.065 (0.049-0.080); OU: 0.085 (0.061-0.138); OT: 0.047 (0.031-0.054), P ≤ 0.053). Collectively, these findings indicate that lifetime endurance exercise appears to be extremely effective at preserving or even enhancing cardiovascular structure and function with advanced age in women.

Efficacy of 10-20-30 training versus moderate-intensity continuous training on HbA1c, body composition and maximum oxygen uptake in male patients with type 2 diabetes: A randomized controlled trial

AIM

To compare the efficacy of 10-20-30 training versus moderate-intensity continuous training (MICT) on HbA1c, body composition and maximum oxygen uptake (V˙O₂ max) in male patients with type 2 diabetes (T2D).

MATERIALS AND METHODS

Fifty-one male participants with T2D were randomly assigned (1:1) to a 10-20-30 (N = 26) and a MICT (N = 25) training group. Interventions consisted of supervised cycling three times weekly for 10 weeks, lasting 29 minutes (10-20-30) and 50 minutes (MICT) in a local non-clinical setting. The primary outcome was change in HbA1c from baseline to 10-week follow-up.

RESULTS

Of 51 participants enrolled, 44 (mean age 61.0 ± 6.8 [mean ± SD] years, diagnosed 7.5 ± 5.8 years, baseline HbA1c 7.4% ± 1.3%) were included in the analysis. Training compliance was 84% and 86% in 10-20-30 and MICT, respectively. No adverse events occurred during the intervention. HbA1c decreased (P <0.001) by 0.5 (95% CI -0.72 to -0.21) percentage points with training in 10-20-30, with no change in MICT. The change in 10-20-30 was greater (P <0.05) than in MICT. Visceral fat mass decreased (P <0.05) only with 10-20-30 training, whereas total fat mass decreased (P <0.01) and V˙O₂ max increased (P <0.01) with training in both groups.

CONCLUSIONS

Ten weeks of 10-20-30 training was superior to MICT in lowering HbA1c, and only 10-20-30 training decreased visceral fat mass in patients with T2D. Furthermore, 10-20-30 training was as effective as MICT in reducing total fat mass and increasing V˙O₂ max, despite a 42% lower training time commitment.

Capillary facilitation of skeletal muscle function in health and disease

Skeletal muscle is highly vascularized, with perfusion being tightly regulated to meet wide-ranging metabolic demands. For decades, the capillary supply has been explored mainly in terms of evaluating the capillary numbers and their function in the supply of oxygen and substrates and the removal of metabolic byproducts. This review will focus on recent discoveries concerning the role played by capillaries in facilitating other aspects of cell regulation and maintenance, in health and disease, as well as alterations during the aging process.

Novelty Capillaries play a central role in the coordination of the vascular response that controls blood flow during contraction and the cellular responses to which they feed into. Nitric oxide is an important regulatory compound within the cardiovascular system, and a significant contributor to skeletal muscle capillary angiogenesis and vasodilatory response to agonists. The microvascular network between muscle fibres may play a critical role in the distribution of signalling factors necessary for optimal muscle satellite cell function.

Pelvic floor muscle training: mechanisms of action for the improvement of genitourinary syndrome of menopause

Objective: This study aims to investigate the mechanism of action of pelvic floor muscle training (PFMT) for the improvement of the signs and symptoms of genitourinary syndrome of menopause (GSM) in postmenopausal women with GSM and urinary incontinence (UI).Methods: Twenty-nine women were included in the secondary analysis of a single-arm feasibility study. Using color Doppler ultrasound, the peak systolic velocity, time-averaged maximum velocity, and pulsatility index of the internal pudendal and dorsal clitoral arteries were measured at rest and after a pelvic floor muscle (PFM) contraction task. PFM function was assessed by dynamometry, and vulvovaginal tissue elasticity was measured using the Vaginal Atrophy Index.Results: PFMT significantly improved blood flow parameters in both arteries (p < 0.05) and significantly increased the speed of PFM relaxation after a contraction (p = 0.003). After the intervention, a marginally significant decrease in PFM tone was observed, as well as an increase in PFM strength (p = 0.060 and p = 0.051, respectively). Finally, improvements in skin elasticity and introitus width were observed as measured by the Vaginal Atrophy Index (p < 0.007).Conclusion: Our findings suggest that PFMT improves blood flow in vulvovaginal tissues, PFM relaxation capacity, and vulvovaginal tissue elasticity in postmenopausal women with GSM and UI.

Cardiac perfusion and function after high-intensity exercise training in late premenopausal and recent postmenopausal women: an MRI study

We examined the influence of recent menopause and aerobic exercise training in women on myocardial perfusion, left ventricular (LV) dimension, and function. Two groups (n = 14 each) of healthy late premenopausal (50.2 ± 2.1 yr) and recent postmenopausal (54.2 ± 2.8 yr) women underwent cardiac magnetic resonance imaging (cMRI) at baseline and after 12 wk of high-intensity aerobic training. Measurements included LV morphology, systolic function, and myocardial perfusion at rest and during an adenosine stress test. At baseline, resting myocardial perfusion was lower in the postmenopausal than the premenopausal group (77 ± 3 vs. 89 ± 3 ml·100 g^-1·min^-1; P = 0.01), while adenosine-induced myocardial perfusion was not different (P = 0.81). After exercise training, resting myocardial perfusion was lower in both groups (66 ± 2; P = 0.002 vs. 81 ± 3 ml·100 g^-1·min^-1; P = 0.03). The adenosine-induced change in myocardial perfusion was lower in the groups combined (by 402 ± 17 ml·100 g^-1·min^-1; P = 0.02), and the adenosine-induced increase in heart rate was 10 ± 2 beats/min lower (P < 0.0001) in both groups after training. Normalization of myocardial perfusion using an estimate of cardiac work eliminated the differences in perfusion between the premenopausal and postmenopausal groups and the effect of training. Left ventricle mass was higher in both groups (P = 0.03; P = 0.006), whereas LV end-diastolic (P = 0.02) and stroke (P = 0.045) volumes were higher in the postmenopausal group after training. Twelve weeks of exercise training increased left ventricle mass and lowered resting and adenosine-induced myocardial perfusion, an effect that was likely related to cardiac work. The current data also suggest that the early menopausal transition has limited impact on cardiac function and structure. NEW & NOTEWORTHY This study provides for the first time estimates of myocardial perfusion in late premenopausal and recent postmenopausal women before and after a period of intense aerobic training. Resting myocardial perfusion was lower in postmenopausal than premenopausal women. Training lowered myocardial resting and stress perfusion in both groups, an effect that was likely influenced by the lower heart rate.

High-intensity exercise training ameliorates aberrant expression of markers of mitochondrial turnover but not oxidative damage in skeletal muscle of men with essential hypertension

AIM

To examine whether hypertensive individuals exhibit altered muscle mitochondrial turnover and redox homeostasis compared with healthy normotensive counterparts, and whether the antihypertensive effect of high-intensity exercise training is associated with improved mitochondrial quality and enhanced anti-oxidant defence.

METHODS

In a cross-sectional and longitudinal parallel design, 24 essential hypertensive (HYP) and 13 healthy normotensive (NORM) men completed 6 weeks of high-intensity interval training (HIIT). Twenty four-hour ambulatory blood pressure, body composition, cardiorespiratory fitness, exercise capacity and skeletal muscle characteristics were examined before and after HIIT. Expression of markers of mitochondrial turnover, anti-oxidant protection and oxidative damage was determined in vastus lateralis muscle biopsies. Muscle protein levels of eNOS and VEGF, and muscle capillarity were also evaluated.

RESULTS

At baseline, HYP exhibited lower expression of markers of mitochondrial volume/biogenesis, mitochondrial fusion/fission and autophagy along with depressed eNOS expression compared with NORM. Expression of markers of anti-oxidant protection was similar in HYP and NORM, whereas oxidative damage was higher in HYP than in NORM. In HYP, HIIT lowered blood pressure, improved body composition, cardiorespiratory fitness and exercise capacity, up-regulated markers of mitochondrial volume/biogenesis and autophagy and increased eNOS and VEGF protein content. Furthermore, in HYP, HIIT induced divergent responses in markers of mitochondrial fusion and anti-oxidant protection, did not affect markers of mitochondrial fission, and increased apoptotic susceptibility and oxidative damage.

CONCLUSION

The present results indicate aberrant muscle mitochondrial turnover and augmented oxidative damage in hypertensive individuals. High-intensity exercise training can partly reverse hypertension-related impairments in muscle mitochondrial turnover, but not redox imbalance.

The Role of Physical Activity Prescription in Cardiovascular Disease Prevention Amongst South Asian Canadians

Unequivocal evidence suggests an increased prevalence of cardiovascular disease (CVD) amongst South Asian Canadians (SACs) compared to other ethnic cohorts, due to a combination of their unique cardiometabolic profile and environmental factors. This unfavorable CVD profile is characterized by an elevated risk of dyslipidemia, high apolipoprotein B/apolipoprotein A1 ratio, hypertension, glucose intolerance, type 2 diabetes mellitus, as well as increased BMI, body fat percentage, abdominal and visceral adiposity. Despite the overwhelming evidence for the effectiveness of physical activity (PA) in circumventing the onset of CVD and in the reduction of CVD risk factors, SACs are among the most physically inactive cohorts in Canada. This relates to a set of common and unique socio-cultural barriers, such as gender, beliefs and perceptions about illness, immigration, unfavorable PA environments, and their high prevalence of debilitating chronic diseases. Several strategies to improve PA participation rates in this high-risk population have been suggested, and include the implementation of culturally sensitive PA interventions, as well as clinician training in PA prescription through workshops that emphasize knowledge translation into clinical practice. Therefore, the purpose of this mini-review is to highlight and discuss: (1) the burden of heart disease in SACs (2) the cardiovascular benefits of PA for SACs; (3) factors affecting PA participation among SACs and how they can be addressed; (4) the impact of culturally sensitive PA prescription on CVD prevention; (5) barriers to culture-specific PA prescription by clinicians, and strategies to improve its use and impact.

Aerobic exercise training lowers platelet reactivity and improves platelet sensitivity to prostacyclin in pre- and postmenopausal women

Essentials It is unknown how regular exercise affects platelet function after menopause. We studied the effect of 3-months of high-intensity exercise in pre- and postmenopausal women. Platelet sensitivity to the inhibitory effect of arterially infused prostacyclin was increased. Reduced basal platelet reactivity was seen in the premenopausal women only.

SUMMARY

Background The risk of atherothrombotic events increases after the menopause. Regular physical activity has been shown to reduce platelet reactivity in younger women, but it is unknown how regular exercise affects platelet function after the menopause. Objectives To examine the effects of regular aerobic exercise in late premenopausal and recent postmenopausal women by testing basal platelet reactivity and platelet sensitivity to prostacyclin and nitric oxide. Methods Twenty-five sedentary, but healthy, late premenopausal and 24 matched recently postmenopausal women, mean (95% confidence interval) 49.1 (48.2-49.9) and 53.7 (52.5-55.0) years old, participated in an intervention study: 3-month high-intensity supervised aerobic spinning-cycle training (1 h, × 3/week). Basal platelet reactivity was analyzed in platelet-rich plasma from venous blood as agonist-induced % aggregation. In a subgroup of 13 premenopausal and 14 postmenopausal women, platelet reactivity was tested ex vivo after femoral arterial infusion of prostacyclin, acetylcholine, a cyclooxygenase inhibitor, and after acute one-leg knee extensor exercise. Results Basal platelet reactivity (%aggregation) to TRAP-6 (1 μm) was higher in the postmenopausal, 59% (50-68), than the premenopausal women, 45% (35-55). Exercise training reduced basal platelet reactivity to collagen (1 μg mL-1 ) in the premenopausal women only: from 63% (55-71%) to 51% (41-62%). After the training intervention, platelet aggregation was more inhibited by the arterial prostacyclin infusion and the acute exercise in both premenopausal and postmenopausal women. Conclusions These results highlight previously unknown cardioprotective aspects of regular aerobic exercise in premenopausal and postmenopausal women, improving their regulation of platelet reactivity through an increased platelet sensitivity to prostacyclin, which may counterbalance the increased atherothrombotic risk associated with the menopause.

Effects of strict prolonged bed rest on cardiorespiratory fitness: systematic review and meta-analysis

The aim of this systematic review and meta-analysis [International Prospective Register of Systematic Reviews (PROSPERO) CRD42017055619] was to assess the effects of strict prolonged bed rest (without countermeasures) on maximal oxygen uptake (V̇o2max) and to explore sources of variation therein. Since 1949, 80 studies with a total of 949 participants (>90% men) have been published with data on strict bed rest and V̇o2max. The studies were conducted mainly in young participants [median age (interquartile range) 24.5 (22.4–34.0) yr]. The duration of bed rest ranged from 1 to 90 days. V̇o2max declined linearly across bed rest duration. No statistical difference in the decline among studies reporting V̇o2max as l/min (−0.3% per day) compared with studies reporting V̇o2max normalized to body weight (ml·kg−1·min−1; −0.43% per day) was observed. Although both total body weight and lean body mass declined in response to bed rest, we did not see any associations with the decline in V̇o2max. However, 15–26% of the variation in the decline in V̇o2max was explained by the pre-bed-rest V̇o2max levels, independent of the duration of bed rest (i.e., higher pre-bed-rest V̇o2max levels were associated with larger declines in V̇o2max). Furthermore, the systematic review revealed a gap in the knowledge about the cardiovascular response to extreme physical inactivity, particularly in older subjects and women of any age group. In addition to its relevance to spaceflight, this lack of data has significant translational implications because younger women sometimes undergo prolonged periods of bed rest associated with the complications of pregnancy and the incidence of hospitalization including prolonged periods of bed rest increases with age.

NEW & NOTEWORTHY Large interindividual responses of maximal oxygen uptake (V̇o2max) to aerobic exercise training exist. However, less is known about the variability in the response of V̇o2max to prolonged bed rest. This systematic review and meta-analysis showed that pre-bed-rest V̇o2max values were inversely associated with the change in V̇o2max independent of the duration of bed rest. Moreover, we identified a large knowledge gap about the causes of decline in V̇o2max, particularly in postmenopausal women, which may have clinical implications.