Exercise training, lipid regulation, and insulin action: a tangled web of cause and effect

Exercise, Physical Activity, and Cardiometabolic Health: Insights into the Prevention and Treatment of Cardiometabolic Diseases

Physical activity (PA) and exercise are widely recognized as essential components of primary and secondary cardiovascular disease (CVD) prevention efforts and are emphasized in the health promotion guidelines of numerous professional societies and committees. The protean benefits of PA and exercise extend across the spectrum of CVD, and include the improvement and reduction of risk factors and events for atherosclerotic CVD (ASCVD), cardiometabolic disease, heart failure, and atrial fibrillation (AF), respectively. Here, we highlight recent insights into the salutary effects of PA and exercise on the primary and secondary prevention of ASCVD, including their beneficial effects on both traditional and nontraditional risk mediators; exercise "prescriptions" for ASCVD; the role of PA regular exercise in the prevention and treatment of heart failure; and the relationships between, PA, exercise, and AF. While our understanding of the relationship between exercise and CVD has evolved considerably, several key questions remain including the association between extreme volumes of exercise and subclinical ASCVD and its risk; high-intensity exercise and resistance (strength) training as complementary modalities to continuous aerobic exercise; and dose- and intensity-dependent associations between exercise and AF. Recent advances in molecular profiling technologies (ie, genomics, transcriptomics, proteomics, and metabolomics) have begun to shed light on interindividual variation in cardiometabolic responses to PA and exercise and may provide new opportunities for clinical prediction in addition to mechanistic insights.

Lifestyle changes in arterial hypertension - an important objective of cardiovascular rehabilitation. The role of physical exercise

Cardiovascular rehabilitation includes lifestyle changing measures, secondary drug prevention and physical training programs. Identifying and addressing cardiovascular risk factors, among which arterial hypertension, is an important objective of cardiovascular rehabilitation. Patients with arterial hypertension should be initially assigned to a cardiovascular risk class. Alongside drug therapy, a healthy diet and physical activity play an important role in the control of blood pressure values Keywords: arterial hypertension, physical exercise,

Metformin May Contribute to Inter-individual Variability for Glycemic Responses to Exercise

Metformin and exercise independently improve glycemic control. Metformin traditionally is considered to reduce hepatic glucose production, while exercise training is thought to stimulate skeletal muscle glucose disposal. Collectively, combining treatments would lead to the anticipation for additive glucose regulatory effects. Herein, we discuss recent literature suggesting that metformin may inhibit, enhance or have no effect on exercise mediated benefits toward glucose regulation, with particular emphasis on insulin sensitivity. Importantly, we address issues surrounding the impact of metformin on exercise induced glycemic benefit across multiple insulin sensitive tissues (e.g., skeletal muscle, liver, adipose, vasculature, and the brain) in effort to illuminate potential sources of inter-individual glycemic variation. Therefore, the review identifies gaps in knowledge that require attention in order to optimize medical approaches that improve care of people with elevated blood glucose levels and are at risk of cardiovascular disease.

Effects of Exercise Training during Christmas on Body Weight and Cardiometabolic Health in Overweight Individuals

Individuals with abdominal obesity and metabolic syndrome (MetS) have augmented risk of all-cause mortality. Lifestyle interventions are effective to treat MetS, however, there are periods during the year in which exercise programs are discontinued and improper dietary habits reappear (e.g., Christmas holidays). We aimed to analyze if exercise-training during Christmas holidays would avoid body-weight gains and cardiometabolic deterioration in MetS individuals, using a randomized control trial. Thirty-eight men with MetS undergoing exercise training were randomly allocated to either continue (TRAIN group, n = 16) or discontinue (HOLID group, n = 22) training, during the three weeks of Christmas. Anthropometrics (body weight, fat, and waist circumference), fasting blood metabolites (glucose, insulin, triglycerides, and cholesterol concentrations) and exercise maximal fat oxidation (FO_MAX) and oxygen uptake (VO_2PEAK) were determined before and after Christmas. Both groups were similar at baseline in all parameters (p > 0.05). HOLID group increased body weight (91.3 ± 13.0 to 92.0 ± 13.4 kg, p = 0.004), mean arterial pressure (94.0 ± 10.6 to 97.1 ± 8.9 mmHg, p = 0.026), blood insulin (10.2 ± 3.8 to 12.5 ± 5.4 µIU·mL⁻¹, p = 0.003) and HOMA (3.2 ± 1.3 to 4.1 ± 2.3, p = 0.003). In contrast, TRAIN prevented those disarrangements and reduced total (170.6 ± 30.6 to 161.3 ± 31.3 mg·dL⁻¹, p = 0.026) and low-density lipoprotein cholesterol (i.e., LDL-_C, 104.8 ± 26.1 to 95.6 ± 21.7 mg·dL⁻¹, p = 0.013). TRAIN also prevented the reductions in exercise FO_MAX and VO_2PEAK that was observed in the HOLID group (p = 0.002). In conclusion, exercise training during Christmas, prevents body weight gains and the associated cardiovascular (increase in blood pressure and LDL_-C) and metabolic (reduced insulin sensitivity) health risks are an optimal non-pharmacological therapy for that period of the year.

Treatment of Obesity in Mitigating Metabolic Risk

Through diverse mechanisms, obesity contributes to worsened cardiometabolic health and increases rates of cardiovascular events. Effective treatment of obesity is necessary to reduce the associated burdens of diabetes mellitus, cardiovascular disease, and death. Despite increasing cardiovascular outcome data on obesity interventions, only a small fraction of the population with obesity are optimally treated. This is a primary impetus for this article in which we describe the typical weight loss, as well as the associated impact on both traditional and novel cardiovascular disease risk factors, provided by the 4 primary modalities for obtaining weight loss in obesity-dietary modification, increasing physical activity, pharmacotherapy, and surgery. We also attempt to highlight instances where changes in metabolic risk are relatively specific to particular interventions and appear at least somewhat independent of weight loss. Finally, we suggest important areas for further research to reduce and prevent adverse cardiovascular consequences due to obesity.

Effects of 12 Weeks of Resistance Training on Cardiovascular Risk Factors in School Adolescents

Background and objectives: The practice of physical exercise, especially resistance exercise, is important for the treatment and/or prevention of cardiovascular risk factors in adult individuals. However, there are few studies on its effects on adolescent individuals. Therefore, the aim of the present study was to evaluate the effects of applying a 12-week resistance training program on cardiovascular risk factors in adolescents. Materials and Methods: Thus, 122 adolescents aged 13-16 years of both genders participated in the study from school in the city of Lagarto, Sergipe (SE), Brazil, divided into two groups: Control Group (CG) and Group undergoing resistance training (RTG). Blood collection and anthropometric measurements were performed before and after the 12-week resistance training program (RTP). Results: After 12 weeks of the RTP in the adolescents, there was a reduction in the triglyceride variables (9.55%, p = 0.0286), Low-Density Lipoproteins (LDL) (5.42%, p = 0.0244), non-High-Density Lipoproteins (HDL) (5.40%, p = 0.0019), blood glucose (6.71%, p = 0.0040), systolic blood pressure (10.13%, p < 0.0001), as well as an increase in the body weight variable (1.73%, p = 0.0003). Conclusions: It was concluded that a 12-week RTP can prevent and/or alleviate the development of several chronic degenerative diseases in adulthood and that resistance training is important for maintaining the health of adolescents.

Beneficial Effect of Ubiquinol on Hematological and Inflammatory Signaling during Exercise

Strenuous exercise (any activity that expends six metabolic equivalents per minute or more causing sensations of fatigue and exhaustion to occur, inducing deleterious effects, affecting negatively different cells), induces muscle damage and hematological changes associated with high production of pro-inflammatory mediators related to muscle damage and sports anemia. The objective of this study was to determine whether short-term oral ubiquinol supplementation can prevent accumulation of inflammatory mediators and hematological impairment associated to strenuous exercise. For this purpose, 100 healthy and well-trained firemen were classified in two groups: Ubiquinol (experimental group), and placebo group (control). The protocol was two identical strenuous exercise tests with rest period between tests of 24 h. Blood samples were collected before supplementation (basal value) (T1), after supplementation (T2), after first physical exercise test (T3), after 24 h of rest (T4), and after second physical exercise test (T5). Hematological parameters, pro- and anti-inflammatory cytokines and growth factors were measured. Red blood cells (RBC), hematocrit, hemoglobin, VEGF, NO, EGF, IL-1ra, and IL-10 increased in the ubiquinol group while IL-1, IL-8, and MCP-1 decreased. Ubiquinol supplementation during high intensity exercise could modulate inflammatory signaling, expression of pro-inflammatory, and increasing some anti-inflammatory cytokines. During exercise, RBC, hemoglobin, hematocrit, VEGF, and EGF increased in ubiquinol group, revealing a possible pro-angiogenic effect, improving oxygen supply and exerting a possible protective effect on other physiological alterations.

Effect of metformin on exercise capacity: A meta-analysis

AIMS

To evaluate the effect of metformin on various parameters of exercise capacity [oxygen consumption (VO₂), peak oxygen consumption (VO_2peak), heart rate (HR), exercise test duration, respiratory exchange ratio (RER), rating of perceived exertion (RPE), lactate and ventilatory anaerobic threshold (VAT)].

METHODS

Studies reporting change in VO₂ or VO_2peak after metformin administration were included. Subgroup analyses were performed as applicable. Mean difference with 95% CIs were pooled using random-effects model [RevMan (v5.3)].

RESULTS

There were no changes in VO₂ and VO_2peak in the overall population [VO₂: n = 388, mean difference: -0.12 ml/kg/min, 95% CI: -0.74, 0.51, p = 0.71 (i² = 0%, p = 0.99); VO_2peak: n = 345, mean difference: 0.41 ml/kg/min, 95% CI: -0.51, 1.33, p = 0.38 (i² = 0%, p = 0.89)], healthy volunteers and patients (type 2 diabetes mellitus, insulin resistance, impaired glucose tolerance/impaired fasting glucose and metabolic syndrome). For patients with insulin resistance, there was a decrease in VO_2peak, but not VO₂. In the overall population, there was a significant decrease in HR and RER, a significant increase in RPE, and no changes in exercise test duration and VAT. In addition, there was an increased VAT in the healthy volunteers.

CONCLUSIONS

In the overall population, metformin did not affect VO₂, VO_2peak, exercise test duration and VAT, although it significantly decreased HR, RER and increased RPE.

Validation and Assessment of Osteoporosis Self-Efficacy Among Iraqi General Population

Background

Poor quality of life, fractures and disability are the consequences of preventable osteoporosis.

Objectives

The aims of this study were to validate and assess Osteoporosis Self-efficacy Scale (OSES-A) Arabic version among Iraqi general population.

Methods

A cross-sectional study with a random cluster sampling method from the community was used. Forward-backward-forward translation method was used to translate the questionnaire from English to Arabic. Beside OSES-A, Osteoporosis Knowledge Tool (OKT) and Osteoporosis Health Belief Scale (OHBS) Arabic versions were used to assess osteoporosis preventive behaviours.

Results

The results showed good face validity and reliability. The construct validity showed two factors which explain 80.86% of the variance. In addition, the result showed low self-efficacy score (658.43±222.014) with 83.33% were found to have low OSES-A level. There were significant associations between age, gender, and self-reported osteoporosis with OSES-A levels. In addition, there were significant differences between age, gender, marital status, family history of osteoporosis, self-reported osteoporosis and osteoporosis diagnosis or screening in relation to total OSES-A scores. Moreover, there were positive correlations between the OSES-A total score with total knowledge and health belief. Multivariate analysis revealed that OKT levels, OHBS levels, age and gender were predictors for OSES-A levels.

Conclusion

This study showed good cultural adaptation and psychometric properties of OSES-A tool and could be used in any osteoprotective educational program.

Improving physical activity after stroke via treadmill training and self management (IMPACT): a protocol for a randomised controlled trial

BACKGROUND

The level of physical activity undertaken by stroke survivors living in the community is generally low. The main objectives of the IMPACT trial are to determine, in individuals undergoing rehabilitation after stroke, if 8 weeks of high-intensity treadmill training embedded in self-management education (i) results in more physical activity than usual physiotherapy gait training and (ii) is more effective at increasing walking ability, cardiorespiratory fitness, self-efficacy, perception of physical activity, participation, and health-related quality of life as well as decreasing cardiovascular risk, and depression, at 8 and 26 weeks.

METHODS

A prospective, two-arm, parallel-group, randomised trial with concealed allocation, blinded measurement and intention-to-treat analysis, will be conducted. 128 stroke survivors undergoing rehabilitation who are able to walk independently will be recruited and randomly allocated to either the experimental or control group, who will both undergo gait training for 30 min, three times a week for 8 weeks under the supervision of a physiotherapist. Outcomes will be measured at baseline (Week 0), on completion of the intervention (Week 8) and beyond the intervention (Week 26). This study has obtained ethical approval from the relevant Human Research Ethics Committees.

DISCUSSION

Improving stroke survivors' walking ability and cardiorespiratory fitness is likely to increase their levels of physical activity. Furthermore, if education in self-management results in sustained high levels of physical activity, this should result in improved participation and quality of life.

TRIAL REGISTRATION

This trial was registered with the Australian New Zealand Clinical Trials Registry ( ACTRN12613000744752 ) on 4th July, 2013.

Psychometric properties and assessment of the Osteoporosis Health Belief Scale among the general Arabic population

BACKGROUND

Any educational program should be implemented with a good understanding of the population's beliefs. Therefore, the aims of this study were to validate the Arabic version of the Osteoporosis Health Belief Scale (OHBS-A) and assess the osteoprotective attitude among the Iraqi population.

METHODS

A cross-sectional design, with a random cluster sampling method from the community, was used. The forward-backward-forward translation method was used to translate the questionnaire from English to Arabic. In addition, the Arabic version of Osteoporosis Knowledge Tool (OKT-A) and the Arabic version of Osteoporosis Self-Efficacy Scale (OSES-A) were used to assess the osteoprotective behaviors.

RESULTS

The results showed good face validity and reliability. The construct validity analysis showed seven factors that explain 72.82% of the variance. In addition, the results revealed a low health belief score (149.95±35.936) with only 36.67% of the study population found to have a high OHBS-A level. The results showed significant differences among employment status, marital status, and osteoporosis (OP) awareness groups in relation to total OHBS-A scores. In addition, there were significant associations between age groups and OP awareness with health belief levels. Moreover, both exercise and calcium intake subscales of the Osteoporosis Knowledge Tool (OKT) positively correlated with all OHBS-A subscales. Exercise and calcium intake subscales of Osteoporosis Self-Efficacy Scale (OSES) positively correlated with the perceived susceptibility and perceived barriers toward exercise and calcium intake. The binary logistic regression analysis showed that OKT levels, OSES levels, and age were predictors of OHBS-A levels.

CONCLUSION

Besides cultural obstacles, an educational program for both genders and all age groups is important and should be tailored according to culture needs.

Effects of endurance training on serum lipids

BACKGROUND AND AIMS

Physical activity is recommended as part of the lifestyle modification for the treatment of hyperlipidemia, however, the literature reports heterogeneous quantitative effects of exercise on serum lipids. We therefore reviewed the effects of aerobic exercise on serum lipids with special focus on the training effectiveness.

METHODS

Data regarding effects of endurance training (ET) on total Cholesterol (TC), LDL-Cholesterol (LDL-C), HDL-Cholesterol (HDL-C) and triglycerides (TG) were evaluated in a selective literature search. To account for the observed heterogeneity of the training interventions, studies were analyzed according to effectiveness (duration, intensity, frequency) of training.

RESULTS

Unselected training intervention studies did not exert significant effects on serum LDL-C but showed minor positive effects on HDL-C and TG. Effective endurance training - defined as endurance training performed by an intensity of 65-75% of the heart rate reserve (corresponding to 75-85% maximum heart rate or 65-80% VO_2max) for a duration of 40-50min per training unit on 3-4days/week over a period of 26-40weeks showed improvement of serum lipids. Effective training lowered TC by -3.75% (p=0.0006), LDL-C by -4.76% (p=0.0015), TG by -8.24% (p=0.0004) and increased HDL-C by +4.43% (p=0.0061).

CONCLUSION

The analysis suggests that a minimum exercise threshold is necessary to produce effects on serum lipids. Overall, the quantitative effect of physical activity on serum lipids is small.

Concurrent aerobic plus resistance exercise versus aerobic exercise alone to improve health outcomes in paediatric obesity: a systematic review and meta-analysis

OBJECTIVE

To determine if the combination of aerobic and resistance exercise is superior to aerobic exercise alone for the health of obese children and adolescents.

DESIGN

Systematic review with meta-analysis.

DATA SOURCES

Computerised search of 3 databases (MEDLINE, EMBASE, and Cochrane Controlled Trials Registry).

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies that compared the effect of supervised concurrent exercise versus aerobic exercise interventions, with anthropometric and metabolic outcomes in paediatric obesity (6-18 years old). The mean differences (MD) of the parameters from preintervention to postintervention between groups were pooled using a random-effects model.

RESULTS

12 trials with 555 youths were included in the meta-analysis. Compared with aerobic exercise alone, concurrent exercise resulted in greater reductions in body mass (MD=-2.28 kg), fat mass (MD=-3.49%; and MD=-4.34 kg) and low-density lipoprotein cholesterol (MD=-10.20 mg/dL); as well as greater increases in lean body mass (MD=2.20 kg) and adiponectin level (MD=2.59 μg/mL). Differences were larger for longer term programmes (>24 weeks).

SUMMARY

Concurrent aerobic plus resistance exercise improves body composition, metabolic profiles, and inflammatory state in the obese paediatric population.

TRIAL REGISTRATION NUMBER

CRD42016039807.

The impact of early aerobic exercise on brain microvascular alterations induced by cerebral hypoperfusion

The therapeutic potential of early exercise training following cerebral hypoperfusion was investigated on brain perfusion and inflammation in rats with permanent bilateral occlusion of the common carotid arteries (2VO). Wistar rats were subjected to 2VO or sham surgery and each group was then subdivided randomly into sedentary or exercise groups. Early exercise training was initiated after three days of 2VO or sham surgery and consisted of seven days of treadmill training (30min/day at ∼60% of maximal exercise test), composing four groups: 1) Sham sedentary (Sham-Sed), 2) Sham exercised (Sham-Ex), 3) 2VO sedentary (2VO-Sed) and 4) 2VO exercised (2VO-Ex). Microvascular cerebral blood flow (MCBF) and NADPH oxidase and eNOS gene expression were evaluated by laser speckle contrast imaging and RT-PCR, respectively, and brain functional capillary density and endothelial-leukocyte interactions were evaluated by fluorescence intravital video-microscopy. The 2VO-Sed group presented a decrease in MCBF (Sham-Sed: 230.9±12.2 vs. 2VO-Sed: 183.6±10.6 arbitrary perfusion units, P<0.05) and in functional capillary density (Sham-Sed: 336.4±25.3 vs. 2VO-Sed: 225.5±28.1capillaries/mm², P<0.05). Early intervention with physical exercise was able to prevent the cerebral microvascular inflammation by decreasing endothelial-leukocyte interactions (2VO-Ex: 0.9±0.3 vs. 2VO-Sed: 5±0.6cells/min/100μm, P<0.0001) and reducing brain NADPH oxidase gene expression (2VO-Ex: 1.7±0.1 arbitrary units, P<0.05). Cerebral microcirculatory and inflammatory alterations appear to be triggered during the first days after 2VO surgery, and early intervention with physical exercise may represent a means of preventing the microvascular alterations induced by chronic cerebral hypoperfusion.

National Lipid Association Annual Summary of Clinical Lipidology 2016

The National Lipid Association (NLA) Annual Summary of Clinical Lipidology is a yearly updated summary of principles important to the patient-centered evaluation, management, and care of patients with dyslipidemia. This summary is intended to be a "living document," with future annual updates based on emerging science, clinical considerations, and new NLA Position, Consensus, and Scientific Statements, thus providing an ongoing resource that applies the latest in medical science towards the clinical management of patients with dyslipidemia. Topics include the NLA Recommendations for Patient-Centered Management of Dyslipidemia, genetics, Familial Hypercholesterolemia, secondary causes of dyslipidemia, biomarkers and advanced lipid testing, nutrition, physical activity, obesity, adiposopathy, metabolic syndrome, diabetes mellitus, lipid pharmacotherapy, lipid-altering drug interactions, lipoprotein apheresis, dyslipidemia management and treatment based upon age (children, adolescents, and older individuals), dyslipidemia considerations based upon race, ethnicity and gender, dyslipidemia and human immune virus infection, dyslipidemia and immune disorders, adherence strategies and collaborative care, and lipid-altering drugs in development. Hyperlinks direct the reader to sentinel online tables, charts, and figures relevant to lipidology, access to online atherosclerotic cardiovascular disease risk calculators, worldwide lipid guidelines, recommendations, and position/scientific statements, as well as links to online audio files, websites, slide shows, applications, continuing medical education opportunities, and patient information.

Moderate-intensity exercise alters markers of alternative activation in circulating monocytes in females: a putative role for PPARγ

PURPOSE

Monocytes may be primed towards differentiation into classically activated M1 macrophages or alternatively activated M2 macrophages. M1 macrophages greatly contribute to the inflammation which promotes insulin resistance, whereas M2 macrophages resolve inflammation. We have previously shown that exercise increases M2 marker expression in mixed mononuclear cells, possibly via activation of the nuclear transcription factor PPARγ. However, these effects have not been demonstrated specifically within monocytes. Thus, we aimed to investigate whether moderate-intensity exercise elicited similar effects on monocytic M1/M2 marker expression and PPARγ activity to those reported previously in mononuclear cells, so as to further elucidate the mechanisms by which exercise may alter inflammatory status and, accordingly, prevent insulin resistance.

METHODS/RESULTS

19 sedentary females completed an 8 week moderate-intensity exercise programme (walking 45 min, thrice weekly). Monocytes were isolated from blood via immunomagnetic separation; monocyte expression of M2 markers (Dectin-1: 2.6 ± 1.9-fold; IL-10: 3.0 ± 2.8-fold) significantly increased, whilst the expression of the M1 marker MCP-1 significantly decreased (0.83 ± 0.2 cf. basal), over the duration of the programme. Serum PPARγ activity levels and PPARγ target-genes (CD36: 1.9 ± 1.5-fold; LXRα: 5.0 ± 4.7-fold) were significantly increased after the 8 week exercise programme. Associated with these effects were significant improvements in systemic insulin sensitivity (McAuley's ISI: Δ0.98 M/mU/L cf. basal).

CONCLUSION

Exercise participation suppressed M1 markers and induced M2 markers in monocytes, potentially via PPARγ-triggered signalling, and these effects may contribute (perhaps via priming of monocytes for differentiation into M2 tissue-macrophages) to improved systemic insulin sensitivity in exercising participants. These findings provide an alternative mechanism by which exercise may exert its anti-inflammatory effects in order to prevent insulin resistance and type 2 diabetes.

Exercise Dose in Clinical Practice

There is wide variability in the physical activity patterns of the patients in contemporary clinical cardiovascular practice. This review is designed to address the impact of exercise dose on key cardiovascular risk factors and on mortality. We begin by examining the body of literature that supports a dose-response relationship between exercise and cardiovascular disease risk factors, including plasma lipids, hypertension, diabetes mellitus, and obesity. We next explore the relationship between exercise dose and mortality by reviewing the relevant epidemiological literature underlying current physical activity guideline recommendations. We then expand this discussion to critically examine recent data pertaining to the impact of exercise dose at the lowest and highest ends of the spectrum. Finally, we provide a framework for how the key concepts of exercise dose can be integrated into clinical practice.

Synergistic association of changes in serum uric acid and triglycerides with changes in insulin resistance after walking exercise in community-dwelling older women

INTRODUCTION

Serum uric acid (SUA) and triglyceride (TG) levels are strongly correlated with insulin resistance; however, the association after a walking exercise program in community-dwelling older women has not been investigated.

METHODS

The present study included 100 postmenopausal women (mean ± standard deviation, 68 ± 7 years) from a rural village in Japan. The Nordic walking program of 120 min per week was performed for 12 weeks. Before and after the intervention, SUA, TG, various relevant factors and homeostasis model assessment of insulin resistance (HOMA-IR) were measured.

RESULTS AND CONCLUSIONS

Multivariate linear regression analysis showed that baseline TG and γ-glutamyltransferase (GGT) were significantly associated with baseline HOMA-IR. After the 12-week training program, changes in TG, SUA and GGT were significantly associated with changes in HOMA-IR. In addition to their direct associations, we observed a synergistic association between changes in TG and SUA and changes in HOMA-IR. Participants were divided into three groups (tertiles) according to changes in TG and SUA. The tertiles of changes in SUA correlated significantly with changes in HOMA-IR in participants in the tertile with the greatest decrease in TG (r = 0.525, p = 0.001), but not in the other two tertiles of change in TG (r = 0.049, p = 0.699). There was a significant interaction between SUA and TG for changes in HOMA-IR (β = 0.281, p = 0.005). These results suggest that changes in TG and SUA are synergistic factors associated with changes in insulin resistance after a 12-week walking exercise program in community-dwelling older women.

The effects of exercise training on the traditional lipid profile and beyond

The purpose of this review is to provide up-to-date information regarding the effects of aerobic and resistance exercise training on the traditional blood lipid and lipoprotein profile. In addition, emerging coronary artery disease (CAD) risk factors, such as postprandial lipemia (PPL) and metabolic syndrome (MetS), are reviewed. Numerous studies report that aerobic exercise combined with weight loss significantly reduces blood cholesterol, low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C), and triglycerides (TG) while improving high-density lipoprotein cholesterol (HDL-C). Both aerobic and resistance training demonstrated a reduction in non-HDL-C independent of changes in body weight. Transient beneficial effects of a single session of aerobic exercise are observed for PPL. Nonetheless further research is needed to provide a better understanding of the potential mechanisms for reducing PPL. Exercise as an intervention for patients with MetS leads to improved CAD risk factors including atherogenic dyslipidemia, blood pressure, body composition, insulin sensitivity, and fat metabolism.

Links between osteoarthritis and diabetes: implications for management from a physical activity perspective

Osteoarthritis (OA) and type 2 diabetes mellitus (T2DM) often coexist in older adults. Those with T2DM are more susceptible to developing arthritis, which has been traditionally attributed to common risk factors, namely, age and obesity. Alterations in lipid metabolism and hyperglycemia might directly impact cartilage health and subchondral bone, contributing to the development/progression of OA. Adequate management of older persons with both conditions benefits from a comprehensive understanding of the associated risk factors. We discuss common risk factors and emerging links between OA and T2DM, emphasizing the importance of physical activity and the implications of safe and effective physical activity.

Manganese superoxide dismutase and oxidative stress modulation

Oxidative stress is characterized by imbalanced reactive oxygen species (ROS) production and antioxidant defenses. Two main antioxidant systems exist. The nonenzymatic system relies on molecules to directly quench ROS and the enzymatic system is composed of specific enzymes that detoxify ROS. Among the latter, the superoxide dismutase (SOD) family is important in oxidative stress modulation. Of these, manganese-dependent SOD (MnSOD) plays a major role due to its mitochondrial location, i.e., the main site of superoxide (O(2)(·-)) production. As such, extensive research has focused on its capacity to modulate oxidative stress. Early data demonstrated the relevance of MnSOD as an O(2)(·-) scavenger. More recent research has, however, identified a prominent role for MnSOD in carcinogenesis. In addition, SOD downregulation appears associated with health risk in heart and brain. A single nucleotide polymorphism which alters the mitochondria signaling sequence for the cytosolic MnSOD form has been identified. Transport into the mitochondria was differentially affected by allelic presence and a new chapter in MnSOD research thus begun. As a result, an ever-increasing number of diseases appear associated with this allelic variation including metabolic and cardiovascular disease. Although diet and exercise upregulate MnSOD, the relationship between environmental and genetic factors remains unclear.

Lipid outcomes from supervised exercise interventions in healthy adults

OBJECTIVES

To meta-analyze lipid outcomes from supervised exercise interventions among healthy adults.

METHODS

Comprehensive search strategies identified trials testing supervised exercise interventions in samples of healthy adults. Data were coded and analyzed using random effects meta-analysis methods. Moderator analyses explored whether design, sample, or intervention characteristics were linked with lipid outcomes.

RESULTS

Data were analyzed from 344 comparisons. The overall mean effect size for 2-group comparisons was 0.28, corresponding to reduced total cholesterol of 8.65 mg/dl. Study effect sizes were greater where participants were obese at baseline, and for interventions utilizing low-intensity exercise.

CONCLUSIONS

Supervised exercise interventions can improve lipid outcomes for healthy adults, with possible greater improvement for obese individuals, and through low-intensity exercise.

National Lipid Association Annual Summary of Clinical Lipidology 2015

The National Lipid Association (NLA) Annual Summary of Clinical Lipidology 2015 is a summary of principles important to the patient-centered evaluation, management, and care of patients with dyslipidemia. This summary is intended to be a "living document," with future annual updates based on emerging science, clinical considerations, and new NLA Position and Consensus Statements. The goal is to provide clinicians an ongoing resource that translates the latest advances in medical science toward the evaluation and treatment of patients with dyslipidemia. The 2015 NLA Annual Summary of Clinical Lipidology was founded on the principles of evidence-based medicine and is generally consistent with established national and international lipid guidelines. Topics include a general discussion of the 2014 NLA Recommendations for Patient-Centered Management of Dyslipidemia, genetics, secondary causes of dyslipidemia, biomarkers and "advanced lipid testing," medical nutrition, physical activity, obesity, pharmacotherapy, statin safety, lipid-altering drug interactions, lipoprotein apheresis, dyslipidemia in children and adolescence, dyslipidemia in older individuals, race/ethnicity, and women, health information technology and electronic medical records, as well as investigational lipid-altering drugs in development.

Early and current physical activity: relationship with intima-media thickness and metabolic variables in adulthood

BACKGROUND

It is unclear whether early physical activity has a greater influence on intima-media thickness and metabolic variables than current physical activity.

OBJECTIVE

To analyze the relationship between current and early physical activity, metabolic variables, and intima-media thickness measures in adults.

METHOD

The sample was composed of 55 healthy subjects of both sexes (33 men and 22 women). Total body fat and trunk fat were estimated by dual-energy X-ray absorptiometry. Carotid and femoral intima-media thickness were measured using a Doppler ultrasound device. A 12-hour fasting blood sample collection was taken (fasting glucose and lipid profile). Early physical activity was assessed through face-to-face interview, and the current physical activity was assessed by pedometer (Digi-Walker Yamax, SW200), which was used for a period of seven days.

RESULTS

Current physical activity was negatively related to total cholesterol (rho=-0.31), while early physical activity was negatively related to triglycerides (rho=-0.42), total cholesterol (rho=-0.28), very low density lipoprotein (rho=-0.44), and carotid intima-media thickness (rho=-0.50). In the multivariate model, subjects engaged in sports activities during early life had lower values of very low density lipoprotein (b=-8.74 [b95%CI=-16.1; -1.47]) and carotid intima-media thickness (b=-0.17 [95%CI: -0.28; -0.05]).

CONCLUSION

Early 95%CI physical activity has a significant influence on carotid intima-media thickness, regardless of the current physical activity.

Insulin Sensitivity Following Exercise Interventions: Systematic Review and Meta-Analysis of Outcomes Among Healthy Adults

OBJECTIVE

Although exercise can improve insulin sensitivity, no adequate synthesis exists of exercise intervention studies with regard to their effect on insulin sensitivity. This comprehensive meta-analysis synthesized the insulin sensitivity outcomes of supervised exercise interventions.

METHOD

Extensive literature searching located published and unpublished intervention studies that measured insulin sensitivity outcomes. Eligible studies tested supervised exercise interventions among healthy adults. Primary study characteristics and results were coded. Random-effects meta-analyses of standardized mean differences included moderator analyses.

RESULTS

Data were synthesized across 2509 subjects (115 samples, 78 reports). The overall mean effect size for 2-group postintervention comparisons was 0.38 (95% confidence interval [CI] = 0.25-0.51, I (2) = 0%) and for 2-group pre-post comparisons was 0.43 (95% CI = 0.30-0.56, I (2) = 52%; higher mean insulin sensitivity for treatment than control subjects). The postintervention mean of 0.38 is consistent with treatment subjects ending studies with a mean fasting insulin of 6.8 mU/L if control participants' mean fasting insulin were 7.9 mU/L. Exploratory moderator analyses did not document different insulin sensitivity effect sizes across intervention characteristics or sample attributes.

CONCLUSION

This study documented that exercise is a valuable primary care and community health strategy for healthy adults to improve insulin sensitivity and lower the risk for diabetes conferred by insulin resistance.

Treadmill Exercise Training Modulates Hepatic Cholesterol Metabolism and Circulating PCSK9 Concentration in High-Fat-Fed Mice

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a novel biomarker of LDL clearance and a therapeutic target of cardiovascular disease. We examined the effects of aerobic exercise training in modulating PCSK9 abundance and hepatic sterol regulation in high-fat-fed C57BL/6 mice. Mice (n = 8) were assigned to a low-fat (LF), high-fat (HF), or an HF with exercise (HF + EX) group for 8 weeks. The HF + EX group was progressively trained 5 days/week on a motorized treadmill. The HF + EX group was protected against body weight (BW) gain and diet-induced dyslipidemia compared with the HF group. The HF + EX group demonstrated an increase in hepatic PCSK9 mRNA (1.9-fold of HF control, P < 0.05) and a reduction in plasma PCSK9 (14%) compared with the HF group. Compared with HF mice, HF + EX mice demonstrated reduced hepatic cholesterol (14%) and increased (P < 0.05) nuclear SREBP2 protein (1.8-fold of HF group) and LDLr mRNA (1.4-fold of HF group). Plasma PCSK9 concentrations correlated positively with plasma non-HDL-C (P = 0.01, r = 0.84). Results suggest that treadmill exercise reduces non-HDL cholesterol and differentially modulates hepatic and blood PCSK9 abundance in HF-fed C57BL/6 mice.

Obesity, adiposity, and dyslipidemia: a consensus statement from the National Lipid Association

The term "fat" may refer to lipids as well as the cells and tissue that store lipid (ie, adipocytes and adipose tissue). "Lipid" is derived from "lipos," which refers to animal fat or vegetable oil. Adiposity refers to body fat and is derived from "adipo," referring to fat. Adipocytes and adipose tissue store the greatest amount of body lipids, including triglycerides and free cholesterol. Adipocytes and adipose tissue are active from an endocrine and immune standpoint. Adipocyte hypertrophy and excessive adipose tissue accumulation can promote pathogenic adipocyte and adipose tissue effects (adiposopathy), resulting in abnormal levels of circulating lipids, with dyslipidemia being a major atherosclerotic coronary heart disease risk factor. It is therefore incumbent upon lipidologists to be among the most knowledgeable in the understanding of the relationship between excessive body fat and dyslipidemia. On September 16, 2012, the National Lipid Association held a Consensus Conference with the goal of better defining the effect of adiposity on lipoproteins, how the pathos of excessive body fat (adiposopathy) contributes to dyslipidemia, and how therapies such as appropriate nutrition, increased physical activity, weight-management drugs, and bariatric surgery might be expected to impact dyslipidemia. It is hoped that the information derived from these proceedings will promote a greater appreciation among clinicians of the impact of excess adiposity and its treatment on dyslipidemia and prompt more research on the effects of interventions for improving dyslipidemia and reducing cardiovascular disease risk in overweight and obese patients.

Cessation of physical exercise changes metabolism and modifies the adipocyte cellularity of the periepididymal white adipose tissue in rats

All of the adaptations acquired through physical training are reversible with inactivity. Although significant reductions in maximal oxygen uptake (Vo2max) can be observed within 2 to 4 wk of detraining, the consequences of detraining on the physiology of adipose tissue are poorly known. Our aim was therefore to investigate the effects of discontinuing training (physical detraining) on the metabolism and adipocyte cellularity of rat periepididymal (PE) adipose tissue. Male Wistar rats, aged 6 wk, were divided into three groups and studied for 12 wk under the following conditions: 1) trained (T) throughout the period; 2) detrained (D), trained during the first 8 wk and detrained during the remaining 4 wk; and 3) age-matched sedentary (S). Training consisted of treadmill running sessions (1 h/day, 5 days/wk, 50-60% Vo2max). The PE adipocyte size analysis revealed significant differences between the groups. The adipocyte cross-sectional area (in μm(2)) was significantly larger in D than in the T and S groups (3,474 ± 68.8; 1,945.7 ± 45.6; 2,492.4 ± 49.08, respectively, P < 0.05). Compared with T, the isolated adipose cells (of the D rats) showed a 48% increase in the ability to perform lipogenesis (both basal and maximally insulin-stimulated) and isoproterenol-stimulated lipolysis. No changes were observed with respect to unstimulated lipolysis. A 15% reduction in the proportion of apoptotic adipocytes was observed in groups T and D compared with group S. The gene expression levels of adiponectin and PPAR-gamma were upregulated by factors of 3 and 2 in D vs. S, respectively. PREF-1 gene expression was 3-fold higher in T vs. S. From these results, we hypothesize that adipogenesis was stimulated in group D and accompanied by significant adipocyte hypertrophy and an increase in the lipogenic capacity of the adipocytes. The occurrence of apoptotic nuclei in PE fat cells was reduced in the D and T rats; these results raise the possibility that the adipose tissue changes after detraining are obesogenic.

Association of physical activity volume and hypercholesterolemia in US adults

BACKGROUND

Several studies illustrate the favorable association between physical activity (PA) and cholesterol levels. There is a paucity of data examining the PA patterns of individuals with and without hypercholesterolemia (HC).

AIM

To examine self-reported moderate and vigorous PA (MVPA) patterns using the most recent PA guidelines among US adults with and without HC.

DESIGN

Cross-sectional study utilizing a secondary data analysis approach.

METHODS

We used data from the 2009 Behavioral Risk Factor Surveillance System (BRFSS). PA categories were based on the 2008 Department of Health and Human Services (DHHS) guidelines.

RESULTS

The age-adjusted prevalence of self-reported HC in US adults was 34%. When stratified by gender, the age-adjusted prevalence of HC was found to be significantly higher in men (36.2%; 95% CI 35.6, 36.8) compared with women (31.8%; 95% CI 31.3, 32.3). The age-adjusted prevalence of meeting the DHHS PA recommendation was 59.1% among participants reporting HC and 68.3% among participants not reporting HC (P < 0.05). Following adjustment for demographics and health history, the odds ratio for meeting the DHHS PA recommendation among participants with HC compared with those without HC was 0.86 (95% CI 0.83, 0.89).

CONCLUSION

Although a large proportion of adults reporting HC report engaging in a volume of MVPA necessary to meet national guidelines, their odds of meeting these guidelines and their MVPA volume may be significantly lower than adults who did not report HC.

Lifestyle impact on meal-induced insulin sensitization in health and prediabetes: A focus on diet, antioxidants, and exercise interventions

The augmented whole-body glucose uptake response to insulin during the postprandial state is described as meal-induced insulin sensitization (MIS). MIS occurs when the presence of food in the upper gastrointestinal tract activates 2 feeding signals (activation of hepatic parasympathetic nerves and elevation of hepatic glutathione level), and causes insulin to release hepatic insulin sensitizing substance (HISS), which stimulates glucose uptake in skeletal muscle, heart, and kidneys. HISS action results in nutrient storage, primarily as glycogen. Impairment of HISS release results in the absence of meal-induced insulin sensitization (AMIS), which causes postprandial hyperglycemia and hyperinsulinemia, and chronically leads to the progression to a cluster of metabolic, vascular, and cardiac dysfunctions, which we refer to as components of the AMIS syndrome. Manipulation of the MIS process in health and in disease, by pharmacological and nonpharmacological interventions, is outlined in this review. High fat or sugar supplemented diet reduces MIS; exercise elevates MIS; and antioxidants protect MIS against reductions associated with diet and age.

Metformin modifies the exercise training effects on risk factors for cardiovascular disease in impaired glucose tolerant adults

Impaired glucose tolerant (IGT) adults are at elevated risk for cardiovascular disease (CVD). Exercise or metformin reduce CVD risk, but the efficacy of combining treatments is unclear.

OBJECTIVE

To determine the effects of exercise training plus metformin (EM), compared with each treatment alone, on CVD risk factors in IGT adults.

DESIGN AND METHODS

Subjects were assigned to placebo (P), metformin (M), exercise training plus placebo (EP), or EM (8/group). In a double-blind design, P or 2,000 mg/d of M were administered for 12 weeks and half performed aerobic and resistance training 3 days/week for ≈ 60 min/day at 70% pretraining heart rate peak. Outcomes included adiposity, blood pressure (BP), lipids, and high sensitivity C-reactive protein (hs-CRP). Z-scores were calculated to determine metabolic syndrome severity.

RESULTS

M and EM, but not EP, decreased body weight compared with P (P < 0.05). M and EP lowered systolic blood pressure by 6% (P < 0.05), diastolic blood pressure by 6% (P < 0.05), and hs-CRP by 20% (M: trend P = 0.06; EP: P < 0.05) compared with P. Treatments raised high-density lipoprotein cholesterol (P < 0.05; EM: trend P = 0.06) compared with P and lowered triacyglycerol (P < 0.05) and metabolic syndrome Z-score compared with baseline (EP; trend P = 0.07 and EM or M; P < 0.05).

CONCLUSIONS

Although exercise and/or metformin improve some CVD risk factors, only training or metformin alone lowered hs-CRP and BP. Thus, metformin may attenuate the effects of training on some CVD risk factors and metabolic syndrome severity in IGT adults.

Chitooligosaccharide induces mitochondrial biogenesis and increases exercise endurance through the activation of Sirt1 and AMPK in rats

By catabolizing glucose and lipids, mitochondria produce ATPs to meet energy demands. When the number and activity of mitochondria are not sufficient, the human body becomes easily fatigued due to the lack of ATP, thus the control of the quantity and function of mitochondria is important to optimize energy balance. By increasing mitochondrial capacity? it may be possible to enhance energy metabolism and improve exercise endurance. Here, through the screening of various functional food ingredients, we found that chitooligosaccharide (COS) is an effective inducer of mitochondrial biogenesis. In rodents, COS increased the mitochondrial content in skeletal muscle and enhanced exercise endurance. In cultured myocytes, the expression of major regulators of mitochondrial biogenesis and key components of mitochondrial electron transfer chain was increased upon COS treatment. COS-mediated induction of mitochondrial biogenesis was achieved in part by the activation of silent information regulator two ortholog 1 (Sirt1) and AMP-activated protein kinase (AMPK). Taken together, our data suggest that COS could act as an exercise mimetic by inducing mitochondrial biogenesis and enhancing exercise endurance through the activation of Sirt1 and AMPK.

Adverse associations of increases in television viewing time with 5-year changes in glucose homoeostasis markers: the AusDiab study

BACKGROUND

Television viewing time is associated cross-sectionally with abnormal glucose tolerance and diabetes risk; however, the impact of changes in television viewing time on glycaemic measures is less understood. We examined relationships of 5-year change in television viewing time with 5-year change in glucose homeostasis markers.

METHODS

Participants in the Australian Diabetes, Obesity and Lifestyle study with data available at the 1999-2000 baseline and the 2004-2005 follow-up were included (4870; 45% men). Television viewing time (h/week) was assessed by questionnaire. Fasting plasma glucose, serum insulin and 2-h plasma glucose were obtained from an oral glucose tolerance test. Beta-cell function and insulin resistance were ascertained using the homeostasis model assessment 2-calculator. Associations of change in television viewing time with changes in glucose homeostasis markers were examined using linear regression models [β-coefficients (95% CI)]. Adjustments included baseline measures of age, television viewing time and glycaemic marker, and baseline and 5-year change in diet quality, energy intake, physical activity and waist circumference.

RESULTS

For every 5-h per week increase in television viewing time from baseline to 5-year follow-up, changes in glucose homeostasis markers were observed: among women there was a significant increase in fasting plasma glucose [0.01 (0.00-0.02) mmol/l] insulin resistance [0.03 (0.01-0.05)] and insulin secretion [1.07 (0.02-2.12) %]; insulin levels increased [men: 1.20 (0.30-2.09); women: 1.06 (0.32-1.80) pmol/l]; in men, 2-h plasma glucose levels increased [0.06 (0.01-0.1) mmol/l].

CONCLUSION

Five-year increases in television viewing time were associated adversely with changes in glucose homeostasis markers. These findings add to earlier cross-sectional evidence that television viewing time can be associated with biomarkers of diabetes risk.

Metabolic profile in two physically active Inuit groups consuming either a western or a traditional Inuit diet

Objectives

To evaluate the effect of regular physical activity on metabolic risk factors and blood pressure in Inuit with high BMI consuming a western diet (high amount of saturated fatty acids and carbohydrates with a high glycemic index).

Study design

Cross sectional study, comparing Inuit eating a western diet with Inuit eating a traditional diet.

Methods

Two physically active Greenland Inuit groups consuming different diet, 20 eating a traditional diet (Qaanaaq) and 15 eating a western diet (TAB), age (mean (range)); 38, (22–58) yrs, BMI; 28 (20–40) were subjected to an oral glucose tolerance test (OGTT), blood sampling, maximal oxygen uptake test, food interview/collection and monitoring of physical activity.

Results

All Inuit had a normal OGTT. Fasting glucose (mmol/l), HbA1c (%), total cholesterol (mmol/l) and HDL-C (mmol/l) were for Qaanaaq women: 4.8±0.2, 5.3±0.1, 4.96±0.42, 1.34±0.06, for Qaanaaq men: 4.9±0.1, 5.7±0.1, 5.08±0.31, 1.28±0.09, for TAB women: 5.1±0.2, 5.3±0.1, 6.22±0.39, 1.86±0.13, for TAB men: 5.1±0.2, 5.3±0.1, 6.23±0.15, 1.60±0.10. No differences were found in systolic or diastolic blood pressure between the groups. There was a more adverse distribution of small dense LDL-C particles and higher total cholesterol and HDL-C concentration in the western diet group.

Conclusions

Diabetes or impaired glucose tolerance was not found in the Inuit consuming either the western or the traditional diet, and this could, at least partly, be due to the high amount of regular daily physical activity. However, when considering the total cardio vascular risk profile the Inuit consuming a western diet had a less healthy profile than the Inuit consuming a traditional diet.

Impact of aerobic exercise training on heart rate variability and functional capacity in obese women after gastric bypass surgery

BACKGROUND

Obesity is a major public health concern on a global scale. Bariatric surgery is among the treatment options, resulting in significant and sustainable weight loss as well as amelioration of comorbidities. The purpose of this study was to evaluate whether a 12-week aerobic exercise program positively impacts heart rate variability (HRV) and functional capacity after gastric bypass surgery (GBS) in a female cohort.

METHODS

Of the 52 patients initially recruited, 21 were randomized to a training group (TG) or control group and successfully completed the study. Patients were tested on two occasions: 1 week before GBS and 4 months after GBS. Anthropometric variables, body composition, record of heart rate and R-R intervals, and 6-min walk test (6MWT) were assessed at both time points. The TG underwent an aerobic exercise training program on a treadmill (1-h session, totaling 36 sessions over 12 weeks).

RESULTS

The main findings from this study were: (1) only the TG demonstrated a significant increase (p < 0.05) in all indexes of heart rate variability (HRV) after 12 weeks of aerobic exercise training and (2) only the TG demonstrated a significant increase (p < 0.05) in 6MWT distance and decrease in diastolic blood pressure after aerobic exercise training.

CONCLUSIONS

We conclude that 12 weeks of aerobic exercise training improves cardiac autonomic modulation and functional capacity 4 months after GBS.

Phlebodium decumanum is a natural supplement that ameliorates the oxidative stress and inflammatory signalling induced by strenuous exercise in adult humans

Strenuous exercise induces muscle damage due to a highly increased generation of free radicals and inflammatory response and therefore, in this type of exercise, it is important to reduce both oxidative stress and inflammation, at least their negative aspects. The purpose of this study was investigate, for the first time, whether a purified, standard water-soluble fraction obtained from Phlebodium decamanum could reduce the over-expression of inflammation and oxidative stress induced by strenuous exercise. The physical test consisted of a constant run that combined several degrees of high effort (mountain run and ultra-endurance), in permanent climbing. Biochemical parameters, oxidative stress and inflammatory mediators were assessed. The results showed that oral supplementation of P. decumanum during high-intensity exercise effectively reduces the degree of oxidative stress (decreased 8-hydroxy-2'-deoxyguanosine and isoprostanes generation, increased antioxidant enzyme activities in erythrocyte and total antioxidant status in plasma). The data obtained also indicate that this supplementation is efficient in reducing the inflammatory response through the decrease of TNF-α and increase of sTNF-RII, but kept the levels of IL-6 and IL-1ra. In conclusion, oral supplementation of P. decamanum extract during high-intensity exercise effectively reduces the degree of oxidative stress and has anti-inflammatory protective effects, preventing the over-expression of TNF-α but keeping the levels and effects of IL-6. These findings provide a basis for similar Phlebodium supplementation for both professional and amateur athletes performing strenuous exercise in order to reduce the undesirable effects of the oxidative stress and inflammation signalling elicited during high-intensity exercise.

Melatonin supplementation ameliorates oxidative stress and inflammatory signaling induced by strenuous exercise in adult human males

Strenuous exercise induces inflammatory reactions together with high production of free radicals and subsequent muscle damage. This study was designed to investigate for the first time and simultaneously whether over-expression of inflammatory mediators, oxidative stress, and alterations in biochemical parameters induced by acute exercise could be prevented by melatonin. This indoleamine is a potent, endogenously produced free radical scavenger and a broad-spectrum antioxidant; consequently, it might have positive effects on the recovery following an exercise session. The participants were classified into two groups: melatonin-treated men (MG) and placebo-treated individuals (controls group, CG). The physical test consisted in a constant run that combined several degrees of high effort (mountain run and ultra-endurance). The total distance of the run was 50 km with almost 2800 m of ramp in permanent climbing and very changeable climatic conditions. Exercise was associated with a significant increase in TNF-α, IL-6, IL-1ra (in blood), and also an increase in 8-hydroxy-2'-deoxyguanosine (8-OHdG) and isoprostane levels (in urine), and indicated the degree of oxidative stress and inflammation induced. Oral supplementation of melatonin during high-intensity exercise proved efficient in reducing the degree of oxidative stress (lower levels of lipid peroxidation, with a significant increase in antioxidative enzyme activities); this would lead to the maintenance of the cellular integrity and reduce secondary tissue damage. Data obtained also indicate that melatonin has potent protective effects, by preventing over-expression of pro-inflammatory mediators and inhibiting the effects of several pro-inflammatory cytokines. In summary, melatonin supplementation before strenuous exercise reduced muscle damage through modulation of oxidative stress and inflammation signaling associated with this physical challenge.

A genome-wide screen for interactions reveals a new locus on 4p15 modifying the effect of waist-to-hip ratio on total cholesterol

Recent genome-wide association (GWA) studies described 95 loci controlling serum lipid levels. These common variants explain ∼25% of the heritability of the phenotypes. To date, no unbiased screen for gene-environment interactions for circulating lipids has been reported. We screened for variants that modify the relationship between known epidemiological risk factors and circulating lipid levels in a meta-analysis of genome-wide association (GWA) data from 18 population-based cohorts with European ancestry (maximum N = 32,225). We collected 8 further cohorts (N = 17,102) for replication, and rs6448771 on 4p15 demonstrated genome-wide significant interaction with waist-to-hip-ratio (WHR) on total cholesterol (TC) with a combined P-value of 4.79×10(-9). There were two potential candidate genes in the region, PCDH7 and CCKAR, with differential expression levels for rs6448771 genotypes in adipose tissue. The effect of WHR on TC was strongest for individuals carrying two copies of G allele, for whom a one standard deviation (sd) difference in WHR corresponds to 0.19 sd difference in TC concentration, while for A allele homozygous the difference was 0.12 sd. Our findings may open up possibilities for targeted intervention strategies for people characterized by specific genomic profiles. However, more refined measures of both body-fat distribution and metabolic measures are needed to understand how their joint dynamics are modified by the newly found locus.

Exercise-induced oxidative stress in humans: cause and consequences

The observation that muscular exercise is associated with oxidative stress in humans was first reported over 30 years ago. Since this initial report, numerous studies have confirmed that prolonged or high-intensity exercise results in oxidative damage to macromolecules in both blood and skeletal muscle. Although the primary tissue(s) responsible for reactive oxygen species (ROS) production during exercise remains a topic of debate, compelling evidence indicates that muscular activity promotes oxidant production in contracting skeletal muscle fibers. Mitochondria, NADPH oxidase, PLA₂-dependent processes, and xanthine oxidase have all been postulated to contribute to contraction-induced ROS production in muscle but the primary site of contraction-induced ROS production in muscle fibers remains unclear. Nonetheless, contraction-induced ROS generation has been shown to play an important physiological function in the regulation of both muscle force production and contraction-induced adaptive responses of muscle fibers to exercise training. Although knowledge in the field of exercise and oxidative stress has grown markedly during the past 30 years, this area continues to expand and there is much more to be learned about the role of ROS as signaling molecules in skeletal muscle.

Effect of combined exercise training on physical and metabolic fitness in adults with intellectual disability: a controlled trial

OBJECTIVE

Investigating the effect of combined aerobic and strength training on metabolic and physical fitness in adults with intellectual disabilities compared to endurance training and no training.

DESIGN

A controlled trial with patients receiving either combined (COM), endurance (END) or no training (C).

SETTING

Two centres for intellectual disabilities (Sterrenhuis, Brasschaat and Emiliani, Lokeren, Belgium).

SUBJECTS

Forty-five adults with intellectual disabilities (mean age: 42 (9,2), mean body mass index (BMI): 24 (3,9), mean IQ: 56 (5,6)).

INTERVENTION

Combined exercise training (n = 15) and endurance training (n = 15) twice a week for 70  minutes per session for 20 weeks and no training (n = 15). Groups were matched for age, sex and intellectual disability.

MAIN MEASURES

Lipid profile, physical fitness (primary); blood pressure and body composition.

RESULTS

Compared to no training, combined exercise training has significant positive effects on total cholesterol levels, aerobic capacity, muscle strength and resting systolic blood pressure, while endurance exercise training has significant effects on aerobic capacity and resting systolic blood pressure. Compared to endurance training, combined exercise training resulted in a significant better evolution of total cholesterol (mean differences: -18 versus -3 mg/dl), 1RM upper (+6 versus +1  kg) and lower limb (+25 versus +8  kg) and abdominal muscles (+15 versus +1  kg), hand grip strength (+9 versus +2  kg), muscle fatigue resistance (+11 versus +5  sec), sit-to-stand (+5 versus +2/30   sec) and systolic blood pressure (-15 versus -10 mmHg).

CONCLUSION

This study revealed a tendency towards more beneficial effects of combined exercise training in adults with intellectual disability.

An essential role for diet in exercise-mediated protection against dyslipidemia, inflammation and atherosclerosis in ApoE⁻/⁻ mice

BACKGROUND

Diet and exercise promote cardiovascular health but their relative contributions to atherosclerosis are not fully known. The transition from a sedentary to active lifestyle requires increased caloric intake to achieve energy balance. Using atherosclerosis-prone ApoE-null mice we sought to determine whether the benefits of exercise for arterial disease are dependent on the food source of the additional calories.

METHODS AND RESULTS

Mice were fed a high-fat diet (HF) for 4.5 months to initiate atherosclerosis after which time half were continued on HF while the other half were switched to a high protein/fish oil diet (HP). Half of each group underwent voluntary running. Food intake, running distance, body weight, lipids, inflammation markers, and atherosclerotic plaque were quantified. Two-way ANOVA tests were used to assess differences and interactions between groups. Exercised mice ran approximately 6-km per day with no difference between groups. Both groups increased food intake during exercise and there was a significant main effect of exercise F((1,44) = 9.86, p<0.01) without interaction. Diet or exercise produced significant independent effects on body weight (diet: F(1,52) = 6.85, p = 0.012; exercise: F(1,52) = 9.52, p<0.01) with no significant interaction. The combination of HP diet and exercise produced a greater decrease in total cholesterol (F(1, 46) = 7.9, p<0.01) and LDL (F(1, 46) = 7.33, p<0.01) with a large effect on the size of the interaction. HP diet and exercise independently reduced TGL and VLDL (p<0.05 and 0.001 respectively). Interleukin 6 and C-reactive protein were highest in the HF-sedentary group and were significantly reduced by exercise only in this group. Plaque accumulation in the aortic arch, a marker of cardiovascular events was reduced by the HP diet and the effect was significantly potentiated by exercise only in this group resulting in significant plaque regression (F1, 49 = 4.77, p<0.05).

CONCLUSION

In this model exercise is beneficial to combat dyslipidemia and protect from atherosclerosis only when combined with diet.

Exercise, abdominal obesity, skeletal muscle, and metabolic risk: evidence for a dose response

The obese are at increased risk for cardiovascular disease and type 2 diabetes. However, some who are obese have no metabolic abnormalities. So, it is not adipose tissue per se, but perhaps where it is located that is important for determining metabolic consequences. Regular exercise is known to reduce risk for metabolic disease through numerous mechanisms. The purpose of this report is to highlight some of the efficacy-based data on the effects of exercise (and also a sedentary lifestyle) on abdominal obesity, visceral fat, and metabolic risk. We also discuss how impaired fatty acid oxidation (FAO) in skeletal muscle may be related to both insulin resistance and a contributor to weight gain. In summary, it is evident that exercise in sufficient amounts can lead to substantial decreases in body weight, total body fat, and visceral fat. Additionally, evidence now supports the conclusion that there is a dose-response relationship between exercise amount and these changes, i.e., more exercise leads to additional benefits. Additionally, there are a number of important cardiometabolic risk factors that were most favorably effected by moderate-intensity compared to vigorous-intensity exercise. Unfortunately, it is also apparent that in sedentary middle-aged men and women, short periods of physical inactivity lead to significant weight gain, substantial increases in visceral fat, and further metabolic deterioration. Finally, favorable modulation of mitochondrial oxidative capacity in skeletal muscle by exercise training may reduce a block for complete oxidation of fatty acids in muscle and thereby relieve a block to effective insulin signaling.