Cardiovascular adaptations to exercise training in postmenopausal women with type 2 diabetes mellitus

Decrease in serum asprosin levels following six weeks of spinning and stationary cycling training in overweight women

OBJECTIVES

Secreted by white adipose tissue, asprosin is a newly recognized adipokine whose physiological function is not well comprehended. This study intended to determine the effect of spinning and stationary cycling on serum asprosin levels in overweight women.

METHODS

Forty-five overweight women with BMI>25 kg/m² in the age range of 30-40 years were assigned randomly to three groups of 15 participants: control, spinning (group cycling with music), and stationary bike (individual pedaling on a stationary bike). The participants performed the exercises three sessions per week for six weeks. Lipid profile and asprosin levels were measured by enzymatic and ELISA methods, respectively. Moreover, the paired t-test and one-way ANOVA were employed to make within-group and between-group comparisons, respectively.

RESULTS

The stationary cycling and spinning exercise groups experienced significant reductions in weight, BMI, serum triglyceride, and asprosin levels from the pretest to the posttest. The control group showed no statistically significant differences. Serum concentrations of total cholesterol and low-density lipoprotein only declined in the spinning group. In this regard, neither the control group nor the stationary bicycle exhibited no significant change over time. The spinning group demonstrated a significant rise in high-density lipoprotein levels, which was not observed in the control group. In addition, there was no significant difference in WHR index between the intervention groups.

CONCLUSIONS

By lowering the serum asprosin level, a spinning exercise program appears to be effective in reducing disorders linked to metabolic diseases in overweight women.

Effect of combined aerobic and resistance exercise on blood pressure in postmenopausal women: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

The purpose of this study is to evaluate the effects of combined aerobic and resistance exercise on blood pressure (BP) in postmenopausal women. The results of this study will provide an effective means for postmenopausal women to control BP and reduce the morbidity and mortality of cardiovascular disease (CVD).

METHODS

Eligible studies were searched in five electronic databases until November 2020, and 11 randomized controlled trials that met the inclusion criteria were included in this systematic review and meta-analysis. The random-effects model was used to calculate overall effect sizes of weighted mean differences (WMD) and 95% confidence interval (CI). This study was registered in PROSPERO with the registration number: CRD42021225546.

RESULTS

Compared with the control group, the aerobic combined resistance exercise significantly decreased the systolic blood pressure (SBP) and diastolic blood pressure (DBP) by 0.81 mmHg (95% CI, -1.34 to -0.28) and 0.62 mmHg (95% CI, -1.11 to -0.14), respectively. The results of the meta-analysis also indicated that a significant reduction in brachial-to-ankle pulse wave velocity (baPWV) of - 1.18 m/s (95% CI, -1.81 to -0.56) and heart rate (HR) of -0.22 beats/min (95% CI: -0.42 to -0.02) after combined aerobic and resistance exercise intervention. Subgroup analysis showed that postmenopausal women ≥60 years of age who were overweight or had a normal baseline BP were more sensitive to the combined aerobic and resistance exercise. When combined aerobic and resistance exercise frequency < 3 times/week, weekly exercise time ≥ 150 min, or the duration of exercise lasted for 12 weeks, the SBP and DBP of postmenopausal women could be reduced more effectively.

CONCLUSIONS

The present study indicates that combined aerobic and resistance exercise can significantly reduce BP in postmenopausal women. Accordingly, combined aerobic and resistance exercise may be an effective way to prevent and manage hypertension in postmenopausal women.

Effects of Combined Resistance and Aerobic Training on Arterial Stiffness in Postmenopausal Women: A Systematic Review

The aim of this systematic review was to investigate the effects of combined resistance and aerobic exercise on arterial stiffness in postmenopausal women. Two databases, PubMed and Google Scholar were searched to identify relevant studies. The methodological quality was assessed with the Physiotherapy Evidence Database (PEDro) scale. Only seven studies met the eligibility criteria, and their outcomes were presented. Four studies demonstrated the effects of combined resistance and aerobic training, while three showed the effectiveness of exercise with both training components, aerobic and resistance. In all studies, arterial stiffness was measured by brachial–ankle pulse wave velocity (baPWV). Participants were middle-aged or older postmenopausal women of various health statuses (hypertensive, with comorbidities or healthy). The results unequivocally show that combined training reduces arterial stiffness. The most important finding of this review paper is that the applied type of exercise decreased baPWV in the range of 0.6–2.1 m/s. Moreover, combined resistance and aerobic exercise for 12 weeks, performed three times a week for about 60 min per training session, at a moderate intensity (40–60% HRR or HRmax), may be clinically meaningful to the cardiovascular system. In conclusion, we can say that combined resistance and aerobic training, or exercise with resistance and aerobic components, have important health implications for the prevention of cardiovascular disease and the maintenance or improvement of health in middle-aged and older postmenopausal women with different health conditions.

The effect of exercise training on blood pressure in menopause and postmenopausal women: A systematic review of randomized controlled trials

The prevalence of hypertension is higher in postmenopausal than in premenopausal women. Regular exercise training has been shown to be effective in addressing hypertension. The aim of this systematic review was to synthesize the effect of exercise training on systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP) in menopausal and postmenopausal women. This review was reported according to the PRISMA statement and registered in PROSPERO. The literature search was done in MEDLINE, Embase, Cochrane CENTRAL and ClinicalTrials. Randomized controlled trials involving menopausal and postmenopausal women undergoing exercise training were included. Two blinded reviewers assessed risk of bias in the included studies by using the Cochrane Risk of Bias tool. A random-effects model was used for all analyses. Significance was set at P < 0.05. Compared with the control group, exercise training resulted in clinically significant reductions on SBP (MD -3.43 mmHg; 95% CI, -5.16, -1.71; P < 0.0001), DBP (MD, -2.25 mmHg; 95% CI, -3.40, -1.11; P = 0.0001) and MAP (MD, -3.48 mmHg; 95% CI, -5.84, -1.11; P = 0.004). Aerobic training (AT) did not produce a significant reduction in SBP, DBP and MAP (P >0.05). Combined training (CT) generated larger reductions. Exercise training generated small but clinically relevant reductions in SBP, DBP and MAP in menopausal and postmenopausal women, younger or older than 65 years, with prehypertension or hypertension. AT did not lead to a clinically relevant improvement in blood pressure (BP) in this population. In addition, CT showed the largest reductions in SBP, DBP and MAP.

The impact of exercise training on inflammatory markers in postmenopausal women: A systemic review and meta-analysis

BACKGROUND

The postmenopausal stage of life is associated with increased systemic inflammation that may be mitigated through exercise training. The effects of exercise training on inflammatory markers in postmenopausal women, however, require further elucidation. We therefore performed a systematic review and meta-analysis to investigate the available high-quality research on the effects of exercise training on inflammatory markers in postmenopausal women.

METHOD

Electronic searches in PubMed, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, and Google Scholar were conducted to identify articles published through April 2021, for studies comparing exercise training to a control condition, on inflammatory markers including CRP, IL-6, TNF-α and adiponectin in postmenopausal women. Randomized or non-randomized controlled trials of exercise training were included according to the following criteria: (A) English language articles; (B) involving women participants who were post-menopausal; (C) providing measures of inflammatory markers including IL-6, TNF-α, CRP or adiponectin at baseline and after completion of the intervention; (D) an exercise training intervention duration of ≥4 weeks.

RESULTS

Results were extracted from the included studies and standardized mean differences (SMD) and 95% confidence intervals (95% CIs) were calculated. Thirty-two studies (representing 38 intervention groups) involving 1510 postmenopausal women were retrieved from the databases for analyses. Overall, exercise training significantly reduced IL-6 [-0.75 (95% CI: -1.07 to -0.42), p < 0.001; 20 interventions], TNF-α [-0.64 (95% CI: -0.91 to -0.37), p < 0.001; 24 interventions] and CRP [-0.64 (95%CI: -0.91 to -0.38), p < 0.001; 21 interventions] and increase adiponectin [0.98 (95% CI: 0.10 to 1.86), p = 0.02; 6 interventions], when compared with control. Furthermore, subgroup analyses suggested that aerobic, resistance, and combined training significantly reduced IL-6, TNF-α and CRP (p < 0.05). Exercise training improved IL-6, TNF-α and CRP in both younger (age < 64 years) and older (age ≥ 64 years) participants (p < 0.05).

CONCLUSION

These results suggest that exercise training may be an effective intervention for reducing pro-inflammatory markers and increasing adiponectin in postmenopausal women.

Effects of Resistance and Combined training on Vascular Function in Type 2 Diabetes: A Systematic Review of Randomized Controlled Trials

BACKGROUND

Cardiovascular disease (CVD) is the main cause of mortality in type 2 diabetes (T2D). Exercise can reduce the risk factors associated with CVD in T2D patients. However, research evaluating its beneficial effects in these patients has used different measurement protocols and types of exercise, complicating comparison.

AIM

To assess the effects of resistance training (RT) and combined training (CT) on the vascular function of T2D patients.

METHODS

A database search (MEDLINE, Scopus, and Web of Science) was performed to identify relevant articles that were published up to August 2017. Only original studies evaluating the effects of RT or CT interventions on vascular function in T2D patients were included. The articles were reviewed independently by at least three reviewers. The Cochrane guidelines were used to assess the methodological quality of the studies. Fourteen studies were finally included. Two studies only used RT and twelve studies used CT as intervention strategy.

RESULTS AND CONCLUSIONS

The results show that resistance training is a useful means for primary treatment of vascular diseases and maintenance of vascular function in T2D patients. However, more studies are necessary to gain full knowledge of the beneficial effects and to identify tailored exercise plans to optimize these benefits. The information provided in this review may help to improve current treatment of vascular diseases in T2D patients and to design future studies.

Physical deconditioning is the common denominator in both obese and overweight subjects with nonalcoholic steatohepatitis

BACKGROUND

Obesity and decreased physical activity mirror increasing prevalence of nonalcoholic fatty liver disease (NAFLD).

AIM

We aimed to investigate associations between aerobic fitness, anthropometrics and disease parameters in patients with nonalcoholic steatohepatitis (NASH). We hypothesised that NASH subjects have lower aerobic power and capacity than untrained, sedentary, normal subjects.

METHODS

Forty subjects (60% obese, 40% overweight) with biopsy-confirmed NASH and NAFLD activity score (NAS) ≥4 were enrolled in a clinical trial where anthropometrics, laboratories, liver fat content by MRI, activity, and aerobic fitness by cycle ergometry data were obtained.

RESULTS

NASH subjects were significantly deconditioned compared to 148 untrained, sedentary, healthy subjects from our laboratory in aerobic power (VO2peak) (NASH 16.8 ± 6.6 vs control 28.4 ± 10.6 mL/kg/min, P < 0.0001) and capacity (VO2 at lactate threshold [LT]) (NASH 8.3 ± 2.5 vs control 14.1 ± 5.9 mL/kg/min, P < 0.0001). NASH subjects' fitness was comparable to the "least fit" tertile of controls: VO2peak [NASH 16.8 ± 6.6 vs "least fit" 17.3 ± 3.3, P = 0.64]) and VO2 at LT (NASH 8.3 ± 2.5 vs "least fit" 9.3 ± 2.1, P = 0.31). Fitness was similar in obese compared to overweight subjects (adjusted for gender) and was not correlated with visceral adiposity or NAS. Engaging in dedicated cardiovascular activity correlated with higher VO2peak and VO2peak at LT.

CONCLUSIONS

Aerobic deconditioning was universally present in NASH subjects. NASH subjects' fitness was similar to our laboratory's "least fit" untrained, sedentary control subjects. Further research investigating NASH patients' ability to improve low baseline aerobic fitness is warranted.

Faster heart rate and muscular oxygen uptake kinetics in type 2 diabetes patients following endurance training

Cardiorespiratory kinetics were analyzed in type 2 diabetes patients before and after a 12-week endurance exercise-training intervention. It was hypothesized that muscular oxygen uptake and heart rate (HR) kinetics would be faster after the training intervention and that this would be detectable using a standardized work rate protocol with pseudo-random binary sequences. The cardiorespiratory kinetics of 13 male sedentary, middle-aged, overweight type 2 diabetes patients (age, 60 ± 8 years; body mass index, 33 ± 4 kg·m^-2) were tested before and after the 12-week exercise intervention. Subjects performed endurance training 3 times a week on nonconsecutive days. Pseudo-random binary sequences exercise protocols in combination with time series analysis were used to estimate kinetics. Greater maxima in cross-correlation functions (CCF_max) represent faster kinetics of the respective parameter. CCF_max of muscular oxygen uptake (pre-training: 0.31 ± 0.03; post-training: 0.37 ± 0.1, P = 0.024) and CCF_max of HR (pre-training: 0.25 ± 0.04; post-training: 0.29 ± 0.06, P = 0.007) as well as peak oxygen uptake (pre-training: 24.4 ± 4.7 mL·kg^-1·min^-1; post-training: 29.3 ± 6.5 mL·kg^-1·min^-1, P = 0.004) increased significantly over the course of the exercise intervention. In conclusion, kinetic responses to changing work rates in the moderate-intensity range are similar to metabolic demands occurring in everyday habitual activities. Moderate endurance training accelerated the kinetic responses of HR and muscular oxygen uptake. Furthermore, the applicability of the used method to detect these accelerations was demonstrated.

Arterial compliance in young children: the role of aerobic fitness

Background

Reduced arterial compliance is reflective of vascular dysfunction, which promotes the atherosclerotic process, and is therefore an important predictor of vascular disease. In adults, obesity, age, aerobic fitness, oestrogens and race influence arterial compliance. Although stature and blood pressure are known to influence compliance in children, other determinants are less established. This investigation sought to determine the predictors of arterial compliance in children, assess the extent to which aerobic fitness is related to compliance, and compare compliance between girls and boys.

Methods

Participants (99 children aged 9-11 years, 55 boys) were assessed for aerobic fitness, physical activity level, blood pressure, body mass, percentage fat mass, height, maturity and arterial compliance (large and small). Predictors of compliance were determined using stepwise regression. Second, children were divided into quartiles according to fitness, and arterial compliance was compared using analysis of covariance (ANCOVA). Finally, differences in compliance between girls and boys were assessed using ANCOVA.

Results

We found that fitness, blood pressure and height accounted for 37% of the variance in large artery compliance. Mass, fitness, maturity and blood pressure accounted for 44% of the variance in small artery compliance. Children in the highest fitness quartile had greater compliance than children in the two lowest quartiles, by as much as 34%. There were no differences in compliance between girls and boys after adjusting for covariates.

Discussion

These data show that aerobic fitness is associated with arterial compliance in 9-11-year-old children, supporting the concept that physical fitness may exert a protective effect on the cardiovascular system.

Targeting skeletal muscle mitochondria to prevent type 2 diabetes in youth

The prevalence of type 2 diabetes (T2D) has increased dramatically over the past two decades, not only among adults but also among adolescents. T2D is a systemic disorder affecting every organ system and is especially damaging to the cardiovascular system, predisposing individuals to severe cardiac and vascular complications. The precise mechanisms that cause T2D are an area of active research. Most current theories suggest that the process begins with peripheral insulin resistance that precedes failure of the pancreatic β-cells to secrete sufficient insulin to maintain normoglycemia. A growing body of literature has highlighted multiple aspects of mitochondrial function, including oxidative phosphorylation, lipid homeostasis, and mitochondrial quality control in the regulation of peripheral insulin sensitivity. Whether the cellular mechanisms of insulin resistance in adults are comparable to that in adolescents remains unclear. This review will summarize both clinical and basic studies that shed light on how alterations in skeletal muscle mitochondrial function contribute to whole body insulin resistance and will discuss the evidence supporting high-intensity exercise training as a therapy to circumvent skeletal muscle mitochondrial dysfunction to restore insulin sensitivity in both adults and adolescents.

Blood and interstitial flow in the hierarchical pore space architecture of bone tissue

There are two main types of fluid in bone tissue, blood and interstitial fluid. The chemical composition of these fluids varies with time and location in bone. Blood arrives through the arterial system containing oxygen and other nutrients and the blood components depart via the venous system containing less oxygen and reduced nutrition. Within the bone, as within other tissues, substances pass from the blood through the arterial walls into the interstitial fluid. The movement of the interstitial fluid carries these substances to the cells within the bone and, at the same time, carries off the waste materials from the cells. Bone tissue would not live without these fluid movements. The development of a model for poroelastic materials with hierarchical pore space architecture for the description of blood flow and interstitial fluid flow in living bone tissue is reviewed. The model is applied to the problem of determining the exchange of pore fluid between the vascular porosity and the lacunar-canalicular porosity in bone tissue due to cyclic mechanical loading and blood pressure. These results are basic to the understanding of interstitial flow in bone tissue that, in turn, is basic to understanding of nutrient transport from the vasculature to the bone cells buried in the bone tissue and to the process of mechanotransduction by these cells.

Combined exercise for people with type 2 diabetes mellitus: a systematic review

Type 2 diabetes mellitus has emerged as a major non-communicable chronic diseases in many countries. The importance of exercise in the prevention and management of this disease is evident. This paper briefly reviews the effects of combining aerobic and resistance exercises on glycemic control, and details the training and characteristics of various interventions in adults with type 2 diabetes mellitus. Literature searches were performed using electronic databases between the 1st of January 1950 and the 15th of September 2011. Of the 403 articles retrieved, 28 studies met our inclusion criteria. Combined exercise protocols seem to improve glycemic control to a greater extent than isolated forms of exercise. Nevertheless, length, duration, intensity, mode, number of exercises, sets and repetitions varied markedly among studies. Supervised training sessions, recommended structured exercises, and splitting aerobic and resistance training in separate sessions may be relevant for best results. Future studies should analyze the effects of different aerobic and resistance training modes, different training and progression methods, and whether one type of exercise is optimal, as these issues are likely to convey greater knowledge on type 2 diabetes mellitus management through combined exercise.

Evidence for sex differences in cardiovascular aging and adaptive responses to physical activity

There are considerable data addressing sex-related differences in cardiovascular system aging and disease risk/progression. Sex differences in cardiovascular aging are evident during resting conditions, exercise, and other acute physiological challenges (e.g., orthostasis). In conjunction with these sex-related differences-or perhaps even as an underlying cause-the impact of cardiorespiratory fitness and/or physical activity on the aging cardiovascular system also appears to be sex-specific. Potential mechanisms contributing to sex-related differences in cardiovascular aging and adaptability include changes in sex hormones with age as well as sex differences in baseline fitness and the dose of activity needed to elicit cardiovascular adaptations. The purpose of the present paper is thus to review the primary research regarding sex-specific plasticity of the cardiovascular system to fitness and physical activity in older adults. Specifically, the paper will (1) briefly review known sex differences in cardiovascular aging, (2) detail emerging evidence regarding observed cardiovascular outcomes in investigations of exercise and physical activity in older men versus women, (3) explore mechanisms underlying the differing adaptations to exercise and habitual activity in men versus women, and (4) discuss implications of these findings with respect to chronic disease risk and exercise prescription.

[Evidence-based guidelines for physical activity of adult Canadians]

This review of the literature provides an update on the scientific biological and psychosocial bases for Canada's Physical Activity Guide for Health Active Living, with particular reference to the effect of physical activity on the health of adults aged 20-55 years. Existing physical activity guidelines for adults from around the world are summarized briefly and compared to the Canadian guidelines. The descriptive epidemiology of physical activity and inactivity in Canada is presented, and the strength of the relationship between physical activity and specific health outcomes is evaluated, with particular emphasis on minimal and optimal physical activity requirements. Finally, areas requiring further investigation are highlighted. Summarizing the findings, Canadian and most international physical activity guidelines advocate moderate-intensity physical activity on most days of the week. Physical activity appears to reduce the risk for over 25 chronic conditions, in particular coronary heart disease, stroke, hypertension, breast cancer, colon cancer, type 2 diabetes, and osteoporosis. Current literature suggests that if the entire Canadian population followed current physical activity guidelines, approximately one-third of deaths related to coronary heart disease, one quarter of deaths related to stroke and osteoporosis, 20% of deaths related to colon cancer, hypertension, and type 2 diabetes, and 14% of deaths related to breast cancer could be prevented. It also appears that the prevention of weight gain and the maintenance of weight loss require greater physical activity levels than current recommendations.

Lipoprotein profile, glycemic control and physical fitness after strength and aerobic training in post-menopausal women with type 2 diabetes

We studied the effects on blood lipids and physical fitness after a training program that combined strength and aerobic exercise in postmenopausal women with type 2 diabetes. Ten patients (55.0 +/- 5.2 years) followed four exercise sessions per week, two strength and two aerobic, and ten (59.4 +/- 3.2 years) served as a control group. Lipid profile, glycated hemoglobin (HbA(1c)), HOMA2 index, exercise stress and muscular testing were assessed at the beginning and after 16 weeks of training program. Exercise training increased significantly HDL-C (17.2%; P < 0.001) and decreased triglycerides (18.9%), HbA(1c) (15.0%), fasting plasma glucose (5.4%), insulin resistance (HOMA2 25.2%) and resting blood pressure (P < 0.01). After 16 weeks of training, exercise time (17.8%) and muscular strength increased significantly (P < 0.001). The results indicated that a combined strength and aerobic training program could induce positive adaptations on lipid profile, glycemic control, insulin resistance, cardiovascular function, and physical fitness in post-menopausal women with type 2 diabetes.

Brisk walking compared with an individualised medical fitness programme for patients with type 2 diabetes: a randomised controlled trial

AIMS/HYPOTHESIS

Structured exercise is considered a cornerstone in type 2 diabetes treatment. However, adherence to combined resistance and endurance type exercise or medical fitness intervention programmes is generally poor. Group-based brisk walking may represent an attractive alternative, but its long-term efficacy as compared with an individualised approach such as medical fitness intervention programmes is unknown. We compared the clinical benefits of a 12-month exercise intervention programme consisting of either brisk walking or a medical fitness programme in type 2 diabetes patients.

METHODS

We randomised 92 type 2 diabetes patients (60 +/- 9 years old) to either three times a week of 60 min brisk walking (n = 49) or medical fitness programme (n = 43). Primary outcome was the difference in changes in HbA1c values at 12 months. Secondary outcomes were differences in changes in blood pressure, plasma lipid concentrations, insulin sensitivity, body composition, physical fitness, programme adherence rate and health-related quality of life.

RESULTS

After 12 months, 18 brisk walking and 19 medical fitness participants were still actively participating. In both programmes, 50 and 25% of the dropout was attributed to overuse injuries and lack of motivation, respectively. Intention-to-treat analyses showed no important differences between brisk walking and medical fitness programme in primary or secondary outcome variables.

CONCLUSIONS/INTERPRETATION

The prescription of group-based brisk walking represents an equally effective intervention to modulate glycaemic control and cardiovascular risk profile in type 2 diabetes patients when compared with more individualised medical fitness programmes. Future exercise intervention programmes should anticipate the high attrition rate due to overuse injuries and motivation problems.

Type 2 diabetes mellitus, resistance training, and innate immunity: is there a common link?

Type 2 diabetes mellitus is a serious chronic disease that is very prevalent in the developed world. The etiology of this disease is not well understood. Recently, the role of the innate immune system in the pathogenesis of type 2 diabetes and its complications has received a great deal of attention. Cytokines, acute phase proteins, and phagocytes have been implicated in this model. Resistance training has known benefits in type 2 diabetic patients and older adults, such as improved insulin action, insulin sensitivity, fasting blood glucose and insulin, and glucose tolerance levels. Actions of pro-inflammatory mediators linked to dysregulated innate immune activity have been associated with type 2 diabetes. The immunomodulatory effects of exercise, and in particular approaches such as resistance training, may provide a strategy to counter these pro-inflammatory effectors. However, the effects of resistance training on innate immunity have not been studied extensively in adults with type 2 diabetes or in older adults who are at increased risk for development of type 2 diabetes. This review discusses the possibility that resistance training may have positive effects on innate immunity in this population and so may provide benefits in addition to improving strength and functional abilities. In particular, the potential of resistance training to modulate pro-inflammatory parameters associated with type 2 diabetes, as a strategy that could provide multiple beneficial health outcomes, is addressed.

Evidence-informed physical activity guidelines for Canadian adultsThis article is part of a supplement entitled Advancing physical activity measurement and guidelines in Canada: a scientific review and evidence-based foundation for the future of Canadian physical activity guidelines co-published by Applied Physiology, Nutrition, and Metabolism and the Canadian Journal of Public Health. It may be cited as Appl. Physiol. Nutr. Metab. 32(Suppl. 2E) or as Can. J. Public Health 98(Suppl. 2)

This review of the literature provides an update on the scientific biological and psychosocial bases for Canada’s physical activity guide for healthy active living, with particular reference to the effect of physical activity on the health of adults aged 20–55 years. Existing physical activity guidelines for adults from around the world are summarized briefly and compared with the Canadian guidelines. The descriptive epidemiology of physical activity and inactivity in Canada is presented, and the strength of the relationship between physical activity and specific health outcomes is evaluated, with particular emphasis on minimal and optimal physical activity requirements. Finally, areas requiring further investigation are highlighted. Summarizing the findings, Canadian and most international physical activity guidelines advocate moderate-intensity physical activity on most days of the week. Physical activity appears to reduce the risk for over 25 chronic conditions, in particular coronary heart disease, stroke, hypertension, breast cancer, colon cancer, type 2 diabetes, and osteoporosis. Current literature suggests that if the entire Canadian population followed current physical activity guidelines, approximately one third of deaths related to coronary heart disease, one quarter of deaths related to stroke and osteoporosis, 20% of deaths related to colon cancer, hypertension, and type 2 diabetes, and 14% of deaths related to breast cancer could be prevented. It also appears that the prevention of weight gain and the maintenance of weight loss require greater physical activity levels than current recommendations.

Cardiovascular disease and osteoporosis: balancing risk management

In this narrative review of the current literature, we examine the traditional risk factors and patient profiles leading to cardiovascular disease and osteoporosis. We discuss the interrelationships between risk factors and common pathophysiological mechanisms for cardiovascular disease and osteoporosis. We evaluate the increasing evidence that supports an association between these disabling conditions. We reveal that vascular health appears to have a strong effect on skeletal health, and vice versa. We highlight the importance of addressing the risk benefit of preventative interventions in both conditions. We discuss how both sexes are affected by these chronic conditions and the importance of considering the unique risk of the individual. We show that habitual physical activity is an effective primary and secondary preventative strategy for both cardiovascular disease and osteoporosis. We highlight how a holistic approach to the prevention and treatment of these chronic conditions is likely warranted.

Role of exercise training in cardiovascular autonomic dysfunction and mortality in diabetic ovariectomized rats

Diabetes and menopause markedly increase the risk of cardiovascular disease in women. The objective of the present study was to investigate the effects of exercise training on cardiovascular autonomic dysfunction and on total mortality in diabetic female rats undergoing ovarian hormone deprivation. Female Wistar rats were divided into ovariectomized groups: sedentary and trained controls and sedentary and trained diabetic rats (streptozotocin, 50 mg/kg IV). Trained groups were submitted to an exercise training protocol on a treadmill (8 weeks). The baroreflex sensitivity was evaluated by heart rate responses to arterial pressure changes. Heart rate variability was determined using the SD of the basal heart rate. Vagal and sympathetic tonus were evaluated by pharmacological blockade. Diabetes impaired baroreflex sensitivity ( approximately 55%), vagal tonus ( approximately 68%), and heart rate variability ( approximately 38%). Exercise training improved baroreflex sensitivity and heart rate variability in control and diabetic groups in relation to their sedentary groups. Trained control rats presented increased vagal tonus compared with that of sedentary ones. The sympathetic tonus was reduced in the trained diabetic group as compared with that of other studied groups. Significant correlations were obtained between heart rate variability and vagal tonus with baroreflex sensitivity. Mortality, assessed during the training period, was reduced in trained diabetic (25%) rats compared with mortality in sedentary diabetic rats (60%). Together, these findings suggest that decreases in baroreflex sensitivity and heart rate variability may be related to increased mortality in female diabetic subjects and that improved autonomic regulation induced by exercise training may contribute to decreased mortality in this population.

Health benefits of physical activity: the evidence

The primary purpose of this narrative review was to evaluate the current literature and to provide further insight into the role physical inactivity plays in the development of chronic disease and premature death. We confirm that there is irrefutable evidence of the effectiveness of regular physical activity in the primary and secondary prevention of several chronic diseases (e.g., cardiovascular disease, diabetes, cancer, hypertension, obesity, depression and osteoporosis) and premature death. We also reveal that the current Health Canada physical activity guidelines are sufficient to elicit health benefits, especially in previously sedentary people. There appears to be a linear relation between physical activity and health status, such that a further increase in physical activity and fitness will lead to additional improvements in health status.