Nordic walking decreased circulating chemerin and leptin concentrations in middle-aged men with impaired glucose regulation

Exercise training modalities in prediabetes: a systematic review and network meta-analysis

Background

Lifestyle modification based on exercise intervention is still the primary way to delay or reverse the development of diabetes in patients with prediabetes. However, there are still challenges in setting up a detailed exercise prescription for people with prediabetes. This study mainly ranks exercise prescriptions by comparing the improvement of glucose and lipid metabolism and the level of weight loss in patients.

Method

All studies on exercise intervention in prediabetes were identified by searching five electronic databases. Risk assessment and meta-analysis were performed on eligible studies.

Results

Twenty-four studies involving 1946 patients with prediabetes and seven exercise intervention models were included in the final analysis. The meta-analysis showed that exercise of any type was more effective for glycemic control in prediabetes than no exercise. However, the changes in blood glucose were moderate. In prediabetes, combining moderate-intensity aerobic exercise with low-to moderate-load resistance training showed the most significant improvements in glycosylated hemoglobin (HbA1c), body mass index (BMI), body weight (BW), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL) (P-score=0.82; 0.70; 0.87; 1; 0.99), low-to moderate-load resistance training showed the most significant improvements in fasting blood glucose (FBG) (P-score=0.98), the vigorous-intensity aerobic exercise showed the most significant improvements in 2-hour post-meal blood glucose (2hPG) and systolic blood pressure (SBP) (P-score=0.79; 0.78), and moderate-intensity aerobic exercise showed the most significant improvements in diastolic blood pressure (DBP) (P-score=0.78).

Conclusion

In summary, moderate-intensity aerobic exercise, low-to moderate-load resistance training and the combination of both have beneficial effects on glycemic control, weight loss, and cardiovascular health in patients with prediabetes. These findings provide valuable guidance for rehabilitation clinicians and patients alike to follow.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD 42021284922.

Aerobic exercise-induced decrease of chemerin improved glucose and lipid metabolism and fatty liver of diabetes mice through key metabolism enzymes and proteins

Our previous studies have implicated an important role of adipokine chemerin in exercise-induced improvements of glycolipid metabolism and fatty liver in diabetes rat, but the underlying mechanisms remain unknown. This study first used an exogenous chemerin supplement to clarify the roles of decreased chemerin in exercised diabetes mice and possible mechanisms of glucose and lipid metabolism key enzymes and proteins [such as adipose triglyceride lipase (ATGL), lipoprotein lipase (LPL), phosphoenolpyruvate carboxykinase (PEPCK), and glucose transporter 4 (GLUT4)]. In addition, two kinds of adipose-specific chemerin knockout mice were generated to demonstrate the regulation of chemerin on glucose and lipid metabolism enzymes and proteins. We found that in diabetes mice, exercise-induced improvements of glucose and lipid metabolism and fatty liver, and exercise-induced increases of ATGL, LPL, and GLUT4 in liver, gastrocnemius and fat were reversed by exogenous chemerin. Furthermore, in chemerin knockdown mice, chemerin(-/-)∙adiponectin mice had lower body fat mass, improved blood glucose and lipid, and no fatty liver; while chemerin(-/-)∙fabp4 mice had hyperlipemia and unchanged body fat mass. Peroxisome proliferator-activated receptor γ (PPARγ), ATGL, LPL, GLUT4 and PEPCK in the liver and gastrocnemius had improve changes in chemerin(-/-)·adiponectin mice while deteriorated alterations in chemerin(-/-)·fabp4 mice, although PPARγ, ATGL, LPL, and GLUT4 increased in the fat of two kinds of chemerin(-/-) mice. CONCLUSIONS: Decreased chemerin exerts an important role in exercise-induced improvements of glucose and lipid metabolism and fatty liver in diabetes mice, which was likely to be through PPARγ mediating elevations of ATGL, LPL and GLUT4 in peripheral metabolic organs.

The effect of exercise training on serum concentrations of chemerin in patients with metabolic diseases: a systematic review and meta-analysis

CONTEXT

Elevated serum concentrations of chemerin is a significant factor in the development of metabolic disorders.

OBJECTIVE

This systematic review and meta-analysis evaluated the influence of exercise training on serum concentrations of chemerin in patients with metabolic diseases.

METHODS

Thirteen studies including 463 participants were included and analysed using a random-effects model to calculate weighted mean differences with 95% confidence intervals.

RESULTS

Results indicated that exercise training significantly decreased serum concentrations of chemerin in patients with metabolic diseases when compared with controls. Subgroup analysis showed that exercise training resulted in decreases in serum concentrations of chemerin in men, however, this was not significant in women. Moreover, subgroup analyses based on the type of exercise did not reveal differential effects on serum concentrations of chemerin.

CONCLUSION

Exercise training may produce improvements in serum concentrations of chemerin in patients with metabolic diseases. Further longer-term studies are needed to confirm these findings.

The effects of exercise training on serum concentrations of chemerin in individuals with overweight and obesity: a systematic review, meta-analysis, and meta-regression of 43 clinical trials

CONTEXT

Elevated serum concentrations of chemerin is a significant factor in the development of metabolic disorders in individuals with overweight and obesity.

OBJECTIVE

This systematic review, meta-analysis, and meta-regression evaluated the effects of exercise training on serum concentrations of chemerin in individuals with overweight and/or obesity.

METHODS

Studies published up to January 2021 were identified through four databases. Forty-three studies including 1271 participants were included and analysed using a random-effects model to calculate weighted mean differences with 95% confidence intervals.

RESULTS

Results indicated that exercise training significantly decreased serum concentrations of chemerin in individuals with overweight and/or obesity. Subgroup analysis showed that all types of exercise (aerobic, resistance, and combined training) interventions but not high-intensity interval training decreased serum concentrations of chemerin. Subgroup analysis based on baseline body mass index (BMI), gender, and intervention duration showed significant declines in serum concentrations of chemerin. Meta-regression analysis indicated a linear relationship between changes in body fat percentage (BFP) with serum concentrations of chemerin.

CONCLUSION

Exercise training may decrease serum concentrations of chemerin in individuals with overweight and/or obesity. The chemerin-lowering effects of exercise might be related to declines in BFP. Further studies are needed to confirm these findings.

Effect of physical activity and different exercise modalities on glycemic control in people with prediabetes: a systematic review and meta-analysis of randomized controlled trials

Background

Numerous studies have shown the beneficial effects of exercise on glycemic control in people with prediabetes. However, the most effective exercise modality for improving glycemic control remains unclear. We aimed to assess which exercise training modality is most effective in improving glycemic control in a population with prediabetes.

Methods

We conducted searches in Pubmed/MEDLINE, EMBASE, SPORTDiscus, Web of Science, PEDro, BVS, and the Cochrane Library from inception to June 2022. Included studies reported fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), and 2-hour postprandial (2hPP) levels and implemented an exercise program lasting at least 12 weeks in adults with prediabetes. We performed a direct meta-analysis using a random-effects model and a network meta-analysis. Cochran's Q statistic and the inconsistency I2 test were used to assess the heterogenicity between studies.

Results

Twenty trials were included, with 15 trials (comprising 775 participants with prediabetes) combined in the meta-analysis, and 13 in the network meta-analysis. The meta-analysis results did not show a statistically significant reduction in fasting plasma glucose (FPG) after aerobic training (AT) intervention compared to a control group (mean (95%CI) difference = -5.18 (-13.48; 3.12) mg/dL, Z=1.22, p=0.22). However, a difference of -7.25 (-13.79; -0.71) mg/dL, p=0.03, in FPG after interval training (IT) intervention was detected compared to a control group. After resistance training (RT) intervention, FPG was significantly lower -6.71 (-12.65,-0.77) mg/dL, Z=2.21, p=0.03, and HbA1c by -0.13 (-0.55, 0.29), p=0.54, compared to the control group. The impact of RT compared to no intervention on 2hPP was not statistically significant (p=0.26). The network meta-analysis did not show statistical significance. Most of the studies presented an unclear risk of bias, and a low and very low-quality of evidence. According to the GRADE criteria, the strength of the body of evidence was low.

Conclusion

Resistance training and IT had demonstrated benefits on glycemic indices, especially on FPG, in a population with prediabetes. Further studies with larger sample sizes and a more robust methodology that compare different types of exercise modalities, frequencies, and durations, are needed to establish a beneficial exercise intervention.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=370688, identifier CRD42022370688.

A review of the impact of energy balance on triple-negative breast cancer

Cancer cells cannot proliferate without sufficient energy to generate biomass for rapid cell division, as well as to fuel their functions at baseline. For this reason, many recent observational and interventional studies have focused on increasing energy expenditure and/or reducing energy intake during and after cancer treatment. The impact of variance in diet composition and in exercise on cancer outcomes has been detailed extensively elsewhere and is not the primary focus of this review. Instead, in this translational, narrative review we examine studies of how energy balance impacts anticancer immune activation and outcomes in triple-negative breast cancer (TNBC). We discuss preclinical, clinical observational, and the few clinical interventional studies on energy balance in TNBC. We advocate for the implementation of clinical studies to examine how optimizing energy balance-through changes in diet and/or exercise-may optimize the response to immunotherapy in people with TNBC. It is our conviction that by taking a holistic approach that includes energy balance as a key factor to be considered during and after treatment, cancer care may be optimized, and the detrimental effects of cancer treatment and recovery on overall health may be minimized.

Impact of Two Types of Exercise Interventions on Leptin and Omentin Concentrations and Indicators of Lipid and Carbohydrate Metabolism in Males with Metabolic Syndrome

Leptin (LEP) and omentin (OMEN) are proteins whose concentrations change with the development of the metabolic syndrome (MetS). There are few intervention studies using various forms of physical activity in people with MetS that aim to determine the impact of physical exercise on the fluctuations of the presented hormones, and their results are contradictory. The present study aimed to examine the effect of two types of exercise intervention on LEP and OMEN concentrations and indicators of lipid and carbohydrate metabolism in males with MetS. The study included 62 males with MetS (age 36.6 ± 6.9 years, body mass 110.31 ± 17.37 kg), randomly allocated to EG1, the examined group with aerobic training (n = 21); EG2, the examined group with combined aerobic and resistance training (n = 21), both for 12 weeks, and the control group (CG) without interventions (n = 20). Anthropometric measurements, body composition (body fat [BF], android body fat [ANDR]), as well as a biochemical blood analysis (omentin [OMEN], leptin [LEP], quantitative insulin sensitivity check index [QUICKI], high-density lipoprotein cholesterol [HDL-C] and nonHDL-C) were performed at baseline, and at 6 and 12 weeks of interventions and after 4 weeks after ending intervention (follow-up). Intergroup and intragroup comparisons were performed. In the intervention groups EG1 and EG2, a decrease in BF was observed as well as an improvement in carbohydrate metabolism parameters. In the EG1 group, the level of ANDR was reduced. In EG2 a decrease in LEP concentration between measurements was confirmed. However, no significant changes were found in the concentration of OMEN in any groups. Combined aerobic and resistance exercises led to a higher reduction of LEP concentration than applying only aerobic training in males with MetS.

Effects of exercise training on inflammatory and cardiometabolic health markers in overweight and obese adults: a systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

The improvements in inflammation and cardiometabolic health play an important role in the prevention and treatment of obesity. However, the interactions between different exercise training (ET) modalities with inflammatory and cardiometabolic biomarkers are not completely understood. This systematic review and meta-analysis investigated the effects of ET on inflammatory and cardiometabolic health markers in overweight and obese adults.

EVIDENCE ACQUISITION

A systematic search was conducted in PubMed, CINAHL, MEDLINE, Cochrane, Google Scholar, Scopus and Web of Science up to December 15, 2021. Thirty-five studies including 2752 participants were included and analyzed using a random-effects model to estimate weighted mean differences (MD) with 95% confidence intervals (CI).

EVIDENCE SYNTHESIS

The meta-analysis found that ET significantly (P<0.05) increased adiponectin (WMD: 0.72 µg/mL; 95% CI: 0.60 to 0.84; SMD=0.65) and maximal oxygen consumption levels (WMD: 5.26 mL.kg.min; 95% CI: 3.84, 6.69; SMD=1.21). Moreover, ET significantly (P<0.05) reduced fasting insulin (WMD: -2.40 μIU/mL; 95% CI: -3.43 to -1.37; SMD=-0.87), fasting blood glucose (WMD: -5.41 mg/dL; 95% CI: -7.91, -2.91; SMD=-0.66), insulin resistance (WMD: -0.66; 95% CI: -1.08, -0.24; SMD=-0.66) and triglyceride levels (WMD: -10.88 mg/dL; 95% CI: -17.61, -4.15; SMD=-0.91). No significant changes were observed in interleukin-6, tumor necrosis factor-α, leptin, C-reactive protein and cholesterol concentrations. Subgroup analysis by type of training indicated that aerobic and resistance exercise had the most consistent beneficial effects as compared to other modalities.

CONCLUSIONS

Our findings suggest that ET may improve inflammation and cardiometabolic health in overweight and obese adults. Aerobic and resistance training appear to be more beneficial for improving adiponectin, fasting insulin, fasting blood glucose, insulin resistance index and triglyceride levels as compared to other exercise modalities. Further long-term studies are required to confirm and expand on these findings.

Comparison of the Effect of Endurance, Strength and Endurance-Strength Training on Glucose and Insulin Homeostasis and the Lipid Profile of Overweight and Obese Subjects: A Systematic Review and Meta-Analysis

The most effective type of training to improve cardiometabolic parameters in overweight subjects is unknown. This meta-analysis compared the effect of endurance, strength and combined training on glucose, insulin metabolism and the lipid profile of overweight and obese adults. The Cochrane, PubMed, Scopus and Web of Science databases were searched to identify randomised trials assessing the effect of training intervention on fasting and 2 h glucose and insulin levels, glycated haemoglobin (HbA1c), homeostatic model assessment of insulin resistance (HOMA), C-peptide, total cholesterol (TC), low- (LDL-C) and high-density lipoprotein cholesterol and triglycerides (TG). Forty-six studies were included showing that endurance training more favourably reduced HbA1c (p = 0.044), and LDL-C (p = 0.021) than strength training. Endurance-strength training more effectively decreased glucose (p = 0.002), HbA1c (p = 0.032), HOMA (p = 0.002), TC (p = 0.039), LDL-C (p = 0.046), HDL (p = 0.036) and TG levels (p = 0.025) than strength training. Combined training significantly reduced the HOMA index (p = 0.009) and TG levels (p = 0.039) compared with endurance training. Endurance and endurance-strength training have a more favourable effect on glucose and insulin homeostasis and lipid profile than strength training in overweight and obese adults. However, the results from this meta-analysis should be interpreted cautiously due to significant heterogeneity among included studies.

Improved Aerobic Capacity and Adipokine Profile Together with Weight Loss Improve Glycemic Control without Changes in Skeletal Muscle GLUT-4 Gene Expression in Middle-Aged Subjects with Impaired Glucose Tolerance

(1) Objective: The aim of this study was to clarify the role of adipokines in the regulation of glucose metabolism in middle-aged obese subjects with impaired glucose tolerance in response to a long-term exercise and dietary intervention. (2) Methods: Skeletal muscle, plasma and serum samples were examined in 22 subjects from an exercise−diet intervention study aiming to prevent type 2 diabetes. The subjects were further divided into two subgroups (non-responders n = 9 and responders n = 13) based on their achievement in losing at least 3 kg. (3) Results: The two-year exercise−diet intervention reduced leptin levels and increased adiponectin levels in responders; the changes in leptin levels were significantly associated with changes in their weights (r = 0.662, p < 0.01). In responders, insulin sensitivity (Bennett and McAuley index) increased and was associated with changes in maximal oxygen uptake (VO2peak) (r = 0.831, p < 0.010 and r = 0.890, p < 0.01). In addition, the VO2peak and oxidative capacity of skeletal muscle improved in responders, but not in non-responders. However, there were no changes between the two groups in expressions of the glucose transporter protein-4 (GLUT-4) gene or of AMP-activated protein kinase (AMPK)-α1 or AMPK-α2 proteins. (4) Conclusions: The exercise−diet intervention decreased serum leptin and increased serum adiponectin concentrations, improved glucose control without affecting GLUT-4 gene expression in the skeletal muscle in responders.

Comparison of the Effect of Endurance, Strength, and Endurance-Strength Training on Inflammatory Markers and Adipokines Levels in Overweight and Obese Adults: Systematic Review and Meta-Analysis of Randomised Trials

The aim of this meta-analysis was to compare the effects of endurance, strength, and combined training on inflammatory markers and adipokine concentrations in overweight and obese adults. We performed a literature search of the Cochrane Library, PubMed, Scopus, and Web of Science databases and identified 24 randomised control trials published prior to June 2021. Our findings indicate that endurance training was significantly more beneficial than strength training in reducing C-reactive protein (CRP) (standard mean difference (SMD): −1.317, 95% confidence intervals (CI): −2.565, −0.070, p = 0.0385), interleukin 6 (IL-6) (SMD: −0.363, 95% CI: −0.648, −0.078, p = 0.0126), and visfatin (SMD: −0.618, 95% CI: −1.015, −0.222, p = 0.0023) concentrations. Moreover, combined training was more beneficial than strength training alone in lowering tumour necrosis factor-alpha (TNF-α) levels (SMD: 0.890, 95% CI: −0.301, 1.478, p = 0.0030). There were no differences between the effects of different types of training programmes on adiponectin and leptin concentrations. In conclusion, compared with strength training, endurance training is more effective in lowering CRP, IL-6, and visfatin concentrations, while combined training is more beneficial in reducing TNF-α levels in overweight and obese adults. Further studies are needed to determine which type of training has a better effect on adiponectin and leptin concentrations in this population.

Resistance training effectiveness on body composition and body weight outcomes in individuals with overweight and obesity across the lifespan: A systematic review and meta-analysis

To systematically review and analyze the effects of resistance-based exercise programs on body composition, regional adiposity, and body weight in individuals with overweight/obesity across the lifespan. Using PRISMA guidelines, randomized controlled trials were searched in nine electronic databases up to December 2020. Meta-analyses were performed using random-effects model. One-hundred sixteen articles describing 114 trials (n = 4184 participants) were included. Interventions involving resistance training and caloric restriction were the most effective for reducing body fat percentage (ES = -3.8%, 95% CI: -4.7 to -2.9%, p < 0.001) and whole-body fat mass (ES = -5.3 kg, 95% CI: -7.2 to -3.5 kg, p < 0.001) compared with groups without intervention. Significant results were also observed following combined resistance and aerobic exercise (ES = -2.3% and -1.4 kg, p < 0.001) and resistance training alone (ES = -1.6% and -1.0 kg, p < 0.001) compared with no training controls. Resistance training alone was the most effective for increasing lean mass compared with no training controls (ES = 0.8 kg, 95% CI: 0.6 to 1.0 kg, p < 0.001), whereas lean mass was maintained following interventions involving resistance training and caloric restriction (ES = ~ - 0.3 kg, p = 0.550-0.727). Results were consistently observed across age and sex groups (p = 0.001-0.011). Reductions in regional adiposity and body weight measures were also observed following combined resistance and aerobic exercise and programs including caloric restriction (p < 0.001). In conclusion, this study provides evidence that resistance-based exercise programs are effective and should be considered within any multicomponent therapy program when caloric restriction is utilized in individuals with overweight or obesity.

Association of Cardiopulmonary Exercise Capacity and Adipokines in the General Population

Adipokines and cardiorespiratory fitness (CRF) are associated with the (patho)physiology of cardiometabolic diseases. Whether CRF and adipokines are related is unclear. We investigated associations of CRF with leptin, adiponectin, chemerin, resistin and vaspin. Data from the population-based Study of Health in Pomerania was used (n=1,479; median age 49 years; 51% women). Cardiopulmonary exercise testing was used to measure CRF. Circulating adipokine concentrations were measured by enzyme-linked immunosorbent assay. The association between CRF and adipokines was assessed using multivariable sex-specific quantile regression models. Higher maximum oxygen uptake was significantly associated with lower leptin (men:-0.11 ng/ml; 95%-confidence interval [CI]:-0.18 to-0.03 ng/ml; p<0.005; women:-0.17 ng/ml; 95%-CI:-0.33 to-0.02 ng/ml; p<0.05) and chemerin (men:-0.26 ng/ml; 95%-CI:-0.52 to-0.01 ng/ml; p<0.05; women:-0.41 ng/ml; 95%-CI:-0.82 to-0.01 ng/ml; p<0.05) as well as higher adiponectin concentrations (men: 0.06 µg/ml; 95%-CI: 0.02 to 0.11 µg/ml; p<0.05; women: 0.03 µg/ml; 95%-CI:-0.05 to 0.10 µg/ml; p=0.48). We found that CRF was inversely associated with leptin and chemerin in both sexes and positively associated with adiponectin only in men.

Comparisons of different exercise interventions on glycemic control and insulin resistance in prediabetes: a network meta-analysis

BACKGROUND

In order to recommend the optimal type of exercise for type 2 diabetes prevention, different exercise interventions were compared with respect to their effects on glycemic control and insulin resistance.

METHODS

Studies on the curative effect of aerobic exercise training (AET), resistance training (RT), or control training (CT) on prediabetes were retrieved from the PubMed, Embase, SPORTDiscus, and Cochrane Library databases. Body mass index (BMI); homeostasis model assessment of insulin resistance index (HOMA-IR); and fasting blood glucose (FBG), glycated hemoglobin (HbA1c), and insulin levels were used as outcome indicators. The Q statistic was calculated to evaluate heterogeneity within studies. A fixed- or random-effects model was used for pooling data based on nonsignificant or significant heterogeneities. A consistency test was conducted using a node-splitting analysis.

RESULTS

A total of 13 eligible studies were included. The results of the direct meta-analysis indicated that AET or RT could significantly reduce the HbA1c level in prediabetic individuals compared to CT [AET vs. CT: standardized mean difference (SMD) = - 0.6739, 95% confidence interval (CI) = - 0.9424 to - 0.4055 to RT vs. CT: SMD = - 1.0014, 95% CI = - 1.3582 to - 0.6446]. The findings from the network meta-analysis showed that there were no statistical differences among the four comparisons for all the indicators except for lower HbA1c level (SMD = - 0.75, 95% CI = - 1.31 to - 0.19) and HOMA-IR (SMD = - 1.03, 95% CI = - 1.96 to - 0.10) in the AET group than in the CT group. In addition, prediabetic individuals in the AET + RT group showed greater control of BMI and insulin and FBG levels than those in the other groups, whereas AET was the most effective in controlling HbA1c and HOMA-IR levels in prediabetic individuals.

CONCLUSION

AET, AET + RT, and RT exerted beneficial effects on insulin resistance and glycemic control in prediabetic patients. From the existing data, AET or AET + RT is preferentially recommended for these patients, although further studies may unveil RT as a promising therapy. Benefits from all types of exercise seem to occur in an intensity-dependent manner.

Determining the effect size of aerobic exercise training on the standard lipid profile in sedentary adults with three or more metabolic syndrome factors: a systematic review and meta-analysis of randomised controlled trials

OBJECTIVES

To estimate the change in the standard lipid profile (SLP) of adults diagnosed with ≥3 metabolic syndrome (MetS) factors following aerobic exercise training (AET); and to investigate whether study/intervention covariates are associated with this change.

DESIGN

Systematic review with univariate meta-analysis and meta-regression.

DATA SOURCES

English language searches of online databases from inception until July 2020. ELIGIBILITY CRITERIA: (1) Published randomised controlled human trials with study population ≥10 per group; (2) sedentary adults with ≥3 MetS factors but otherwise free of chronic disease, not pregnant/lactating; (3) AET-only intervention with duration ≥12 weeks; and (4) reporting pre-post intervention SLP outcomes.

RESULTS

Various univariate meta-analyses pooled 48 data sets of 2990 participants. Aerobic exercise training significantly (P<.001) improved all lipids (mmol/L mean difference ranges, 95% CIs): total cholesterol, -0.19 (-0.26 to -0.12) to -0.29 (-0.36 to -0.21); triglycerides, -0.17 (-0.19 to -0.14) to -0.18 (-0.24 to -0.13); high-density lipoprotein-cholesterol (HDL-C), 0.05 (0.03 to 0.07) to 0.10 (0.05 to 0.15); and low-density lipoprotein-cholesterol (LDL-C), -0.12 (-0.16 to -0.9) to -0.20 (-0.25 to -0.14). Meta-regression showed that intensity may explain change in triglycerides and volume may explain change in HDL-C and LDL-C.

CONCLUSION

Aerobic exercise training positively changes the SLP of sedentary and otherwise healthy adults with ≥3 MetS factors. Adjusting AET intervention training variables may increase the effects of AET on triglycerides and HDL-C.

PROSPERO REGISTRATION NUMBER

CRD42020151925.

Comparing the effects of 12 months aerobic exercise and resistance training on glucose metabolism among prediabetes phenotype: A explorative randomized controlled trial

AIMS

The pathophysiology of each phenotype of prediabetes is unique that promotes different levels of diabetes and cardiovascular disease risks. Exercise guidelines for individuals with prediabetes including both aerobic and resistance training could improve metabolic control, but its effects on different prediabetes subtypes are unclear. The aim of this explorative randomized controlled trial was to evaluate the effects of aerobic training (AT) or resistance training (RT) on glucose metabolism and lipid profile by different prediabetes subtypes with.

METHODS

A randomized controlled trial in which 128 individuals with isolated impaired fasting glucose (i-IFG; n = 39), isolated impaired glucose tolerance (i-IGT; n = 29), combined glucose tolerance (CGI; n = 27) and isolated elevated HbA_1c (n = 33) were randomly assigned to the control group, AT group and RT group, respectively. Supervised exercise training, including AT and RT were completed at moderate intensity for 60 min per day, three non-consecutive days per week for 12 months. The primary outcome was improvement in glucose metabolism. Secondary outcomes included measure of lipid profile and if these effects were moderated by the prediabetes phenotype.

RESULTS

Of the initial 128 participants, 118 finished the study, but all participants were included in the intention-to-treat analyses. The improvement in 2 h postprandial plasma glucose (2 hPG) between group difference (AT vs. RT) at 12 months was 0.87 (95% CI, -1.59 to-0.16; p < 0.05). Compared with RT group, AT significantly decreased the 2hPG in participants with i-IGT at 12 months (-1.66, 95% CI -3.04 to -0.28; p < 0.05).

CONCLUSIONS

AT program conferred benefits in improving 2 h PG and HbA_1c compared with RT for prediabetes. These findings may moderate by prediabetes phenotype, and AT appeared more effective in i-IGT. A future trial with large sample size and long time follow up of prediabetes phenotype groups are needed.

Effect of physical activity promotion on adiponectin, leptin and other inflammatory markers in prediabetes: a systematic review and meta-analysis of randomized controlled trials

AIMS

Inflammatory stage in prediabetes is associated with increase in level of adipokines and pro-inflammatory cytokines. Physical activity promotion considered as a first-line therapeutic strategy to treat prediabetes. We have conducted the systematic review and meta-analysis to strengthen the evidence on the impact of physical activity promotion on inflammatory markers in prediabetes.

METHODS

Studies were identified using electronic search and manual search techniques by choosing keywords for prediabetes, physical activity and inflammatory marker. Randomized controlled trials on individuals diagnosed with prediabetes and provided intervention in the form of physical activity were included in this review. Adiponectin, leptin, C-reactive protein, interleukin-6 and tumour necrosis factor-α were the considered outcome measures.

RESULTS

Our search retrieved 1,688 citations, 31 full-text articles assessed for eligibility of inclusion. Nine studies satisfied the pre-specified criteria for inclusion. Meta-analysis found that physical activity with or without dietary or lifestyle modification reduces level of leptin (MD-2.11 ng/mL, 95% CI -3.81 - -0.42) and interleukin-6 (MD -0.15 pg/mL, 95% CI -0.25--0.04). It has no effect on level of adiponectin (MD 0.26 µg/mL, 95% CI -0.42- 0.93), C-reactive protein (MD -0.05 mg/L, 95% CI -0.33-0.23) and tumour necrosis factor-α (MD 0.67 pg/mL, 95% CI -2.56-3.89).

CONCLUSIONS

This review suggests that physical activity promotion with dietary and lifestyle modification may reduce the level of leptin and interleukin-6 but are uncertain if there is any effect on levels of adiponectin, C-reactive protein and tumour necrosis factor-α in the individuals with prediabetes.

Walking for hypertension

BACKGROUND

Increased physical activity has been recommended as an important lifestyle modification for the prevention and control of hypertension. Walking is a low-cost form of physical activity and one which most people can do. Studies testing the effect of walking on blood pressure have revealed inconsistent findings.

OBJECTIVES

To determine the effect of walking as a physical activity intervention on blood pressure and heart rate.

SEARCH METHODS

We searched the following databases up to March 2020: the Cochrane Hypertension Specialised Register, CENTRAL (2020, Issue 2), Ovid MEDLINE, Ovid Embase, CINAHL, PsycINFO, SPORTDiscus, PEDro, the WHO International Clinical Trials Registry Platform, and ClinicalTrials.gov. We also searched the following Chinese databases up to May 2020: Index to Taiwan Periodical Literature System; National Digital Library of Theses and Dissertation in Taiwan; China National Knowledge Infrastructure (CNKI) Journals, Theses & Dissertations; and Wanfang Medical Online. We contacted authors of relevant papers regarding further published and unpublished work. The searches had no language restrictions.

SELECTION CRITERIA

Randomised controlled trials of participants, aged 16 years and over, which evaluated the effects of a walking intervention compared to non-intervention control on blood pressure and heart rate were included.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Where data were not available in the published reports, we contacted authors. Pooled results for blood pressure and heart rate were presented as mean differences (MDs) between groups with 95% confidence intervals (CIs). We undertook subgroup analyses for age and sex. We undertook sensitivity analyses to assess the effect of sample size on our findings.

MAIN RESULTS

A total of 73 trials met our inclusion criteria. These 73 trials included 5763 participants and were undertaken in 22 countries. Participants were aged from 16 to 84 years and there were approximately 1.5 times as many females as males. The characteristics of walking interventions in the included studies were as follows: the majority of walking interventions was at home/community (n = 50) but supervised (n = 36 out of 47 reported the information of supervision); the average intervention length was 15 weeks, average walking time per week was 153 minutes and the majority of walking intensity was moderate. Many studies were at risk of selection bias and performance bias. Primary outcome We found moderate-certainty evidence suggesting that walking reduces systolic blood pressure (SBP) (MD -4.11 mmHg, 95% CI -5.22 to -3.01; 73 studies, n = 5060). We found moderate-certainty evidence suggesting that walking reduces SBP in participants aged 40 years and under (MD -4.41 mmHg, 95% CI -6.17 to -2.65; 14 studies, n = 491), and low-certainty evidence that walking reduces SBP in participants aged 41 to 60 years (MD -3.79 mmHg, 95% CI -5.64 to -1.94, P < 0.001; 35 studies, n = 1959), and those aged 60 years of over (MD -4.30 mmHg, 95% CI -6.17 to -2.44, 24 studies, n = 2610). We also found low certainty-evidence suggesting that walking reduces SBP in both females (MD -5.65 mmHg, 95% CI -7.89 to -3.41; 22 studies, n = 1149) and males (MD -4.64 mmHg, 95% CI -8.69 to -0.59; 6 studies, n = 203). Secondary outcomes We found low-certainty evidence suggesting that walking reduces diastolic blood pressure (DBP) (MD -1.79 mmHg, 95% CI -2.51 to -1.07; 69 studies, n = 4711) and heart rate (MD -2.76 beats per minute (bpm), 95% CI -4.57 to -0.95; 26 studies, n = 1747). We found moderate-certainty evidence suggesting that walking reduces DBP for participants aged 40 years and under (MD -3.01 mmHg, 95% CI -4.44 to -1.58; 14 studies, n = 491) and low-certainty evidence suggesting that walking reduces DBP for participants aged 41 to 60 years (MD -1.74 mmHg, 95% CI -2.95 to -0.52; 32 studies, n = 1730) and those aged 60 years and over (MD -1.33 mmHg, 95% CI -2.40 to -0.26; 23 studies, n = 2490). We found moderate-certainty evidence that suggests walking reduces DBP for males (MD -2.54 mmHg, 95% CI -4.84 to -0.24; 6 studies, n = 203) and low-certainty evidence that walking reduces DBP for females (MD -2.69 mmHg, 95% CI -4.16 to -1.23; 20 studies, n = 1000). Only 21 included studies reported adverse events. Of these 21 studies, 16 reported no adverse events, the remaining five studies reported eight adverse events, with knee injury being reported five times.

AUTHORS' CONCLUSIONS

Moderate-certainty evidence suggests that walking probably reduces SBP. Moderate- or low-certainty evidence suggests that walking may reduce SBP for all ages and both sexes. Low-certainty evidence suggests that walking may reduce DBP and heart rate. Moderate- and low-certainty evidence suggests walking may reduce DBP and heart rate for all ages and both sexes.

The effects of physical activity on adipokines in individuals with overweight/obesity across the lifespan: A narrative review

This narrative review summarizes current knowledge on the effects of physical activity (PA) on adipokine levels in individuals with overweight and obesity. Approximately 90 investigations including randomized control, cross-sectional and longitudinal studies that reported on the effects of a single session of PA (acute) or long-term PA (chronic) on adipokine levels in individuals with overweight/obesity were reviewed. The findings support the notion that there is consensus on the benefits of chronic exercise training-regardless of the mode (resistance vs. aerobic), intensity and cohort (healthy vs. diabetes)-on adipokine levels (such as tumour necrosis factor-alpha, interleukin-6, adiponectin, visfatin, omentin-1 and leptin). However, several confounding factors (frequency, intensity, time and type of exercise) can alter the magnitude of the effects of an acute exercise session. Available evidence suggests that PA, as a part of routine lifestyle behaviour, improves obesity complications by modulating adipokine levels. However, additional research is needed to help identify the most effective interventions to elicit the most beneficial changes in adipokine levels in individuals with overweight/obesity.

Anti-Inflammatory Effects of Exercise on Metabolic Syndrome Patients: A Systematic Review and Meta-Analysis

BACKGROUND

Increments in inflammatory indicators and low levels of physical activity are correlated to the expansion of the metabolic syndrome (MetS).

OBJECTIVE

The purpose of this study was to establish if exercise training ameliorates inflammatory status in MetS patients.

DATA SOURCES

PubMed, CINAHL, and Medline, Google Scholar, and Scopus databases and reference lists of included studies were searched.

STUDY SELECTION

Twenty randomized controlled trials (RCTs) of exercise-training impact on inflammatory markers (tumor necrosis factor (TNF) α, C-reactive protein (CRP), interleukin (IL) 6, IL-8, IL-10, and IL-18) with concurrent control groups were included in this analysis.

RESULTS

Results demonstrated an overall significant decrease in serum levels of TNF-α (mean difference (MD): -1.21 pg/ml; 95% confidence interval (CI): -1.77, -0.66), CRP (MD: -0.52 mg/l; 95% CI: -0.79, -0.25), IL-8 (MD: -1.31 pg/ml; 95% CI: -2.57, -0.06), and a significant increase in IL-10 (MD: 0.48 pg/ml; 95% CI: 0.10, 0.86). But exercise training did not change the level of IL-6 (MD: -0.69 pg/ml; 95% CI: -1.53, 0.14) and IL-18 (MD: -53.01 pg/ml; 95% CI: -166.64, 60.62).

CONCLUSION

Exercise training improves TNF-α, CRP, IL-8, and IL-10 levels in patients with MetS. For some variables, isolated aerobic exercise, and combined aerobic and resistance exercise appears to be optimal. Future research is needed to clarify the mechanisms underlying exercise training's effect on this population's inflammatory markers. More studies are required to confirm these findings.

Changes in Lipoinflammation Markers in People with Obesity after a Concurrent Training Program: A Comparison between Men and Women

Obesity is related to low-grade systemic inflammation. This state of inflammation is characterized by the alteration in adipokine regulation, which may lead to a situation of cardiometabolic risk. The aim of this study was to evaluate the effects of a concurrent training program on markers of lipoinflammation in adult people with obesity, comparing the response to the training between men and women. A quasi-experimental, quantitative, and longitudinal study with a pre–post intervention was conducted. An 8-week concurrent training program was carried out, in which 26 individuals with obesity participated (mean ± SD; age = 46.38 ± 4.66) (BMI = 36.05 ± 4.99) (12 men and 14 women). Before and after the intervention period, blood samples were taken by percutaneous puncture. The blood levels of adiponectin and leptin were evaluated. Significant differences were obtained in the adiponectin–leptin ratio (A/L ratio) of the entire sample (p = 0.009, ES = 0.53), which indicates a decrease in the risk of cardiovascular diseases and lipoinflammation. There were no significant differences in the improvements observed after the training in A/L ratio between women (A/L change = +63.5%) and men (A/L change= +59.2%). It can be concluded that the combination of aerobic exercise and resistance training induced an improvement in markers of lipoinflammation and cardiometabolic risk in the individuals with obesity evaluated in this study.

Effects of a Supervised Nordic Walking Program on Obese Adults with and without Type 2 Diabetes: The C.U.R.I.A.Mo. Centre Experience

Exercise is a convenient non-medical intervention, commonly recommended in metabolic syndrome and type 2 diabetes (DM2) managements. Aerobic exercise and aerobic circuit training have been shown to be able to reduce the risk of developing DM2-related complications. Growing literature proves the usefulness of Nordic walking as exercise therapy in different disease populations, therefore it has a conceivable use in DM2 management. Aims of this study were to analyze and report the effects of two different supervised exercises (gym-based exercise and Nordic walking) on anthropometric profile, blood pressure values, blood chemistry and fitness variables in obese individuals with and without DM2. In this study, 108 obese adults (aged 45-65 years), with or without DM2, were recruited and allocated into one of four subgroups: (1) Gym-based exercise program (n = 49) or (2) Nordic walking program (n = 37) for obese adults; (3) Gym-based exercise program (n = 10) or (4) Nordic walking program (n = 12) for obese adults with DM2. In all exercise subgroups, statistically significant improvements in body weight, body mass index, fat mass index, muscular flexibility and maximal oxygen uptake (VO2 max) were observed. Moreover, a higher percentage of adherence to the gym-based program compared to Nordic walking was recorded. Our findings showed that, notwithstanding the lower adherence, a supervised Nordic walk is effective as a conventional gym-based program to improve body weight control, body composition parameters, muscular flexibility and VO2 max levels in obese adults with and without type 2 diabetes.

Nordic Walking for Overweight and Obese People: A Systematic Review and Meta-Analysis

BACKGROUND

Nordic walking (NW) is a potentially beneficial exercise strategy for overweight and obese people. To date, no reviews have synthesized the existing scientific evidence regarding the effects of NW on this population. This systematic review and meta-analysis aimed to identify the characteristics, methodological quality, and results of the investigations that have studied the effects of NW in overweight and obese individuals.

METHODS

Six electronic databases were searched up to June 2019 for studies that examined the effects of NW on people with a body mass index ≥ 25 kg/m2. The methodological quality of the included randomized controlled trials was retrieved from the physiotherapy evidence database or evaluated using the physiotherapy evidence database scale.

RESULTS

Twelve studies were included in the review. The investigations were mostly good-to-fair methodological quality. NW groups had a significant improvement on parameters such as fasting plasma glucose, abdominal adiposity, and body fat compared with the baseline, but no significant improvements were found when compared with control groups.

CONCLUSIONS

NW can potentially lead to improvements in parameters related to major health outcomes in overweight and obese people. The lack of control for confounding variables in the analyzed studies prevents further elaboration on its potential benefits.

Chemerin: A Potential Regulator of Inflammation and Metabolism for Chronic Obstructive Pulmonary Disease and Pulmonary Rehabilitation

Chronic obstructive pulmonary disease (COPD) features chronic inflammatory reactions of both intra- and extrapulmonary nature. Moreover, COPD is associated with abnormal glucose and lipid metabolism in patients, which influences the prognosis and chronicity of this disease. Abnormal glucose and lipid metabolism are also closely related to inflammation processes. Further insights into the interactions of inflammation and glucose and lipid metabolism might therefore inspire novel therapeutic interventions to promote lung rehabilitation. Chemerin, as a recently discovered adipokine, has been shown to play a role in inflammatory response and glucose and lipid metabolism in many diseases (including COPD). Chemerin recruits inflammatory cells to sites of inflammation during the early stages of COPD, leading to endothelial barrier dysfunction, early vascular remodeling, and angiogenesis. Moreover, it supports the recruitment of antigen-presenting cells that guide immune cells as part of the body's inflammatory responses. Chemerin also regulates metabolism via activation of its cognate receptors. Glucose homeostasis is affected via effects on insulin secretion and sensitivity, and lipid metabolism is changed by increased transformation of preadipocytes to mature adipocytes through chemerin-binding receptors. Controlling chemerin signaling may be a promising approach to improve various aspects of COPD-related dysfunction. Importantly, several studies indicate that chemerin expression in vivo is influenced by exercise. Although available evidence is still limited, therapeutic alterations of chemerin activity may be a promising target of therapeutic approaches aimed at the rehabilitation of COPD patients based on exercises. In conclusion, chemerin plays an essential role in COPD, especially in the inflammatory responses and metabolism, and has a potential to become a target for, and a biomarker of, curative mechanisms underlying exercise-mediated lung rehabilitation.

Comparing the effects of 6 months aerobic exercise and resistance training on metabolic control and β-cell function in Chinese patients with prediabetes: A multicenter randomized controlled trial

BACKGROUND

It is clear that aerobic training (AT) can delay pancreatic exhaustion and slow the progression from prediabetes to type 2 diabetes (T2D), but there is little information regarding the effects of resistance training (RT) in people with prediabetes. This study compared the effectiveness of RT and AT in improving metabolic control and protecting β-cell function in people with prediabetes.

METHODS

Chinese subjects (n = 248) with prediabetes were randomized to three groups: AT (n = 83), RT (n = 82) and control (n = 83). Subjects in the RT group performed 13 different resistance exercises per session using an elastic string. Those in the AT group performed aerobic exercises at 60%-70% of maximum heart rate. In both cases, exercises were performed three times per week for a period of 6 months. The primary outcome was improvement in metabolic control. Longitudinal changes between groups were tested using repeated-measures analysis of variance.

RESULTS

Of the initial 248 participants, 217 finished the study, but all participants were included in the intention-to-treat analyses. There were no significant differences in demographic characteristics among the RT, AT, and control groups (P > 0.05). Changes in HbA1c were not significantly greater in RT than AT cohort (P = 0.059), but the decrease in HbA1c in both exercise groups was higher than in the control group (P < 0.05).

CONCLUSIONS

In subjects with prediabetes, RT appears to improve metabolic control and preserve β-cell function comparable to AT.

Nordic Walking Promoted Weight Loss in Overweight and Obese People: A Systematic Review for Future Exercise Prescription

The aim of this systematic review was to analyze the effect of Nordic Walking (NW) on anthropometric parameters, body composition, cardiovascular parameters, aerobic capacity, blood sample, and glucose tolerance in overweight and obese subjects. The main keywords "Nordic Walking" or "Pole Walking", associated with either "obese", "obesity", "overweight", or "weight loss" were used on the online database MEDLINE, PubMed, SPORTDiscus and Scopus. Additionally, references of the studies included were screened to identify eligible articles. Applying the inclusion and exclusion criteria, ten manuscripts were considered as eligible for this review. The results of the studies were categorized in several domains with regard to "anthropometric parameters and body composition", "cardiovascular parameters and aerobic capacity", and "blood sample and glucose tolerance". The results showed positive effects on the anthropometric parameters, body composition, cardiovascular parameters, blood sample, and glucose tolerance. The greatest improvements were observed in supervised and high weekly frequency of NW interventions. NW could be considered as an effective modality through which to involve the obese in physical activity. For weight loss, NW should be prescribed 4-5 times per week, at least 60 min per session, preferably combined with diet control.

Aerobic exercise decreases chemerin/CMKLR1 in the serum and peripheral metabolic organs of obesity and diabetes rats by increasing PPARγ

Objective

To investigate the influences of exercise on the levels of chemerin and its receptor chemokine-like receptor (CMKLR1) in the peripheral metabolic organs of obesity and diabetes rats, and whether the mechanism is related to peroxisome proliferator activated receptor γ (PPARγ), a key modulator of glycolipid metabolism.

Methods

Obesity rats induced by 8-week high fat diet (HFD) were randomly divided into obesity group (OB) and exercised obesity group (EOB) with 8 rats each group, and 40 diabetes rats established by 8-week HFD plus low dose of streptozotocin were randomly divided into 4 groups: diabetes group (DM), exercised diabetes group (EDM), exercised diabetes plus PPARγ agonist pioglitazone group (EDP), and exercised diabetes plus PPARγ antagonist GW9662 group (EDG). The rats in EOB, EDM, EDG and EDP groups participated in a 4-week moderate-intensity aerobic exercise on a treadmill with gradually increasing intensity, once a day and 6 days/week, and 30 min before each exercise EDP and EDG were administrated to the rats in EDP and EDG groups, respectively. Before and after 4-week exercise, glycolipid metabolism indexes, serum chemerin and the levels of chemerin and CMKLR1 in metabolic organs such as liver and gastrocnemius were investigated (not detecting adipose for no available perirenal adipose from DM rats).

Results

(1) In addition to serum chemerin, the levels of chemerin and CMKLR1 in the liver and gastrocnemius of EOB and EDM rats were declined, accompanied with the improved glycolipid metabolism. (2) The decreased chemerin/CMKLR1 in the EDM rats were reversed by PPARγ antagonist GW9662 and further strengthened by PPARγ agonist pioglitazones.

Conclusions

Besides serum chemerin, the levels of chemerin/CMKLR1 in the metabolic organs of obesity and diabetes rats were alleviated by exercise, which were likely to be associated with the improvement of glycolipid metabolism. Exercise-induced decrements of chemerin/CMKLR1 in the diabetes rats were mediated by PPARγ.

Electronic supplementary material

The online version of this article (10.1186/s12986-019-0344-9) contains supplementary material, which is available to authorized users.

Obesity and cancer risk: Emerging biological mechanisms and perspectives

Continuously rising trends in obesity-related malignancies render this disease spectrum a public health priority. Worldwide, the burden of cancer attributable to obesity, expressed as population attributable fraction, is 11.9% in men and 13.1% in women. There is convincing evidence that excess body weight is associated with an increased risk for cancer of at least 13 anatomic sites, including endometrial, esophageal, renal and pancreatic adenocarcinomas; hepatocellular carcinoma; gastric cardia cancer; meningioma; multiple myeloma; colorectal, postmenopausal breast, ovarian, gallbladder and thyroid cancers. We first synopsize current epidemiologic evidence; the obesity paradox in cancer risk and mortality; the role of weight gain and weight loss in the modulation of cancer risk; reliable somatometric indicators for obesity and cancer research; and gender differences in obesity related cancers. We critically summarize emerging biological mechanisms linking obesity to cancer encompassing insulin resistance and abnormalities of the IGF-I system and signaling; sex hormones biosynthesis and pathway; subclinical chronic low-grade inflammation and oxidative stress; alterations in adipokine pathophysiology; factors deriving from ectopic fat deposition; microenvironment and cellular perturbations including vascular perturbations, epithelial-mesenchymal transition, endoplasmic reticulum stress and migrating adipose progenitor cells; disruption of circadian rhythms; dietary nutrients; factors with potential significance such as the altered intestinal microbiome; and mechanic factors in obesity and cancer. Future perspectives regarding prevention, diagnosis and therapeutics are discussed. The aim of this review is to investigate how the interplay of these main potential mechanisms and risk factors, exerts their effects on target tissues provoking them to acquire a cancerous phenotype.

Classic and Novel Adipocytokines at the Intersection of Obesity and Cancer: Diagnostic and Therapeutic Strategies

PURPOSE OF REVIEW

In this review, we investigate the role of classic and novel adipocytokines in cancer pathogenesis synopsizing the mechanisms underlying the association between adipocytokines and malignancy. Special emphasis is given on novel adipocytokines as new evidence is emerging regarding their entanglement in neoplastic development.

RECENT FINDINGS

Recent data have emphasized the role of the triad of overweight/obesity, insulin resistance and adipocytokines in cancer. In the setting of obesity, classic and novel adipocytokines present independent and joint effects on activation of major intracellular signaling pathways implicated in cell proliferation, expansion, survival, adhesion, invasion, and metastasis. Until now, more than 15 adipocytokines have been associated with cancer, and this list continues to expand. While the plethora of circulating pro-inflammatory adipocytokines, such as leptin, resistin, extracellular nicotinamide phosphoribosyl transferase, and chemerin are elevated in malignancies, some adipocytokines such as adiponectin and omentin-1 are generally decreased in cancers and are considered protective against carcinogenesis. Elucidating the intertwining of inflammation, cellular bioenergetics, and adiposopathy is significant for the development of preventive, diagnostic, and therapeutic strategies against cancer. Novel more effective and safe adipocytokine-centered therapeutic interventions may pave the way for targeted oncotherapy.

Progressive circuit resistance training improves inflammatory biomarkers and insulin resistance in obese men

BACKGROUND

Circuit resistance training (CRT) is a time-efficient exercise modality for improving skeletal muscle and cardiovascular fitness. But the beneficial role of CRT in obese individuals is still not well understood. This study explores the reducing effects of progressive CRT on inflammatory biomarkers and cardiometabolic risk factors in obese young men.

METHODS

Thirty obese men (Body mass index (BMI): 30.67 ± 3.06; age: 23 ± 3.2 years) were divided into CRT and control groups. The CRT was performed for eight-weeks (3 times/week, 65-85% of 1 repetition maximum). Fasting blood samples were taken pre and post intervention for analyzing apelin, chemerin, serum amyloid A (SAA), C reactive protein concentrations (CRP), lipid profile, and insulin resistance index. The data were assessed by two-way repeated measures ANOVA.

RESULTS

Body mass, BMI and waist to hip ratio (WHR) were significantly decreased after training intervention (P < .05). Compared to the control group, the plasma concentrations of Chemrin (P = .038), SAA (P = .004), insulin (P < .001), insulin resistance index (P < .001), total cholesterol (P = .033), triglyceride (P < .001), and low-density lipoprotein (P = .039), were significantly mitigated in the CRT group, but high-density lipoprotein plasma levels increased in the CRT group compared to that of the control group (P = .035). There was no significant difference between two groups in apelin and CRP (P > .05). Moreover, insulin resistance was positively correlated with apelin (r = 0.56) and chemerin (r = 0.51). Also, chemerin had a positive correlation with SAA (r = 0.49), and WHR (r = 0.54).

CONCLUSION

CRT caused an improvement in inflammation and cardiometabolic risk factors in young obese men, and this improvement was accompanied by decreased insulin resistance.

The Effect of Chronic Exercise Training on Leptin: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Leptin is a hormone associated with satiety, lipid oxidation, energy expenditure, and energy homeostasis. To date, the current body of research examining the effect of chronic exercise training on leptin has yielded inconsistent results.

OBJECTIVE

The purpose of this meta-analysis was to provide a quantitative estimate of the magnitude of change in leptin levels following participation in exercise interventions lasting ≥ 2 weeks.

METHODS

All studies included were peer-reviewed and published in English. To be included, studies randomized human participants to an exercise training group or non-exercise comparison group for an exercise training intervention. Leptin levels were measured at baseline, during, and/or after completion of the exercise training program. Random-effects models were used to aggregate a mean effect size (ES) and 95% confidence intervals (CIs), and identify potential moderators.

RESULTS

Seventy-two randomized controlled trials met the inclusion criteria and resulted in 107 effects (n = 3826). The mean ES of 0.24 (95% CI 0.16-0.32, p < 0.0001) indicated a decrease in leptin following an exercise training program. A decrease in %Fat (β = - 0.07, p < 0.01) was associated with a decrease in leptin after accounting for the type of control group (β = - 0.38, p < 0.0001) used in each study.

CONCLUSION

These results suggest that engaging in chronic exercise training (≥ 2 weeks) is associated with a decrease in leptin levels for individuals regardless of age and sex. However, a greater decrease in leptin occurred with a decreased percentage of body fat.

Plasma irisin is increased following 12 weeks of Nordic walking and associates with glucose homoeostasis in overweight/obese men with impaired glucose regulation

Irisin is a myokine that is thought to be secreted in response to exercise that may help to prevent obesity and maintain normal glucose metabolism. In this study we investigated the associations between irisin and glucose homeostasis in middle-aged, overweight and obese men (n =  144) with impaired glucose regulation, and the impact of exercise training on these relationships. The participants underwent 12 weeks of resistance or aerobic (Nordic walking) exercise training three times per week, 60 minutes per session. Venous blood (n = 105) and skeletal muscle samples (n = 45) were obtained at baseline and post-intervention. Compared to controls, Nordic walking, but not resistance training, increased irisin levels in plasma (9.6 ± 4.2%, P = 0.014; 8.7 ±  4.9%, P = 0.087; respectively) compared to controls. When considering all subjects, baseline irisin correlated positively with atherogenic index of plasma (r = 0.244, P = 0.013) and 2-hour insulin levels (r = 0.214, P = 0.028), and negatively with age (r = -0.262, P = 0.007), adiponectin (r = -0.240, P = 0.014) and McAuley index (r = -0.259, P = 0.008). Training-induced FNDC5 mRNA changes were negatively correlated with HbA1c (r = -0.527, P = 0.030) in the resistance training group and with chemerin in the Nordic walking group (r = -0.615, P = 0.033). In conclusion, 12-weeks of Nordic walking was more effective than resistance training in elevating plasma irisin, in middle-aged men with impaired glucose tolerance. Thus, the change in irisin in response to exercise training varied by the type of exercise but showed limited association with improvements in glucose homeostasis.

Humanin skeletal muscle protein levels increase after resistance training in men with impaired glucose metabolism

Humanin (HN) is a mitochondrially encoded and secreted peptide linked to glucose metabolism and tissue protecting mechanisms. Whether skeletal muscle HN gene or protein expression is influenced by exercise remains unknown. In this intervention study we show, for the first time, that HN protein levels increase in human skeletal muscle following 12 weeks of resistance training in persons with prediabetes. Male subjects (n = 55) with impaired glucose regulation (IGR) were recruited and randomly assigned to resistance training, Nordic walking or a control group. The exercise interventions were performed three times per week for 12 weeks with progressively increased intensity during the intervention period. Biopsies from the vastus lateralis muscle and venous blood samples were taken before and after the intervention. Skeletal muscle and serum protein levels of HN were analyzed as well as skeletal muscle gene expression of the mitochondrially encoded gene MT‐RNR2, containing the open reading frame for HN. To elucidate mitochondrial training adaptation, mtDNA, and nuclear DNA as well as Citrate synthase were measured. Skeletal muscle HN protein levels increased by 35% after 12 weeks of resistance training. No change in humanin protein levels was seen in serum in any of the intervention groups. There was a significant correlation between humanin levels in serum and the improvements in the 2 h glucose loading test in the resistance training group. The increase in HN protein levels in skeletal muscle after regular resistance training in prediabetic males may suggest a role for HN in the regulation of glucose metabolism. Given the preventative effect of exercise on diabetes type 2, the role of HN as a mitochondrially derived peptide and an exercise‐responsive mitokine warrants further investigation.

Decrease in serum chemerin through aerobic exercise plus dieting and its association with mitigation of cardio-metabolic risk in obese female adolescents

BACKGROUND

The objective of this study was to determine the effects of a 4-week aerobic exercise plus dieting intervention on serum chemerin in obese female adolescents and its possible role in mitigating cardio-metabolic risk including glucose and lipid metabolism, central fat and inflammation.

METHODS

Fifty obese female adolescents were randomly divided into two groups: exercise plus dieting group (n=30) and dieting group (n=20). The participants in the exercise plus dieting group completed 4 weeks of moderate aerobic exercise combined with dieting, while the subjects in the dieting group undertook only dieting. Before and after the experiments, anthropometric index, parameters of glucose and lipid metabolism, serum chemerin and classic inflammatory indicators (C-reactive protein [CRP], tumor necrosis factor-α [TNF-α], interleukin-1β [IL-1β], IL-6, leptin and adiponectin) were measured.

RESULTS

Compared with the dieting group, a decrease in serum chemerin was found in the exercise plus dieting group, accompanied by significant improvements in anthropometric index, glucose and lipid metabolism and inflammatory factors. In addition, a higher serum chemerin level was found in obese adolescents with metabolic syndrome (MetS), and the disappearance of MetS induced by exercise plus dieting might be related to the decrease in chemerin. Correlation analysis showed the correlations of the decrease in chemerin with the changes in body fat, glucose and lipid metabolic index, leptin and adiponectin/leptin ratio.

CONCLUSIONS

This is the first report that as short a duration as 4-week aerobic exercise plus dieting decreased serum chemerin in obese female adolescents, which might be associated with the improvement in glucose and lipid metabolism, mitigation of inflammation and decrease in MetS incidence, thus lowering cardio-metabolic risk, while no health benefit resulted from slight dieting.

Sarcopenic obesity or obese sarcopenia: A cross talk between age-associated adipose tissue and skeletal muscle inflammation as a main mechanism of the pathogenesis

Sarcopenia, an age-associated decline in skeletal muscle mass coupled with functional deterioration, may be exacerbated by obesity leading to higher disability, frailty, morbidity and mortality rates. In the combination of sarcopenia and obesity, the state called sarcopenic obesity (SOB), some key age- and obesity-mediated factors and pathways may aggravate sarcopenia. This review will analyze the mechanisms underlying the pathogenesis of SOB. In obese adipose tissue (AT), adipocytes undergo hypertrophy, hyperplasia and activation resulted in accumulation of pro-inflammatory macrophages and other immune cells as well as dysregulated production of various adipokines that together with senescent cells and the immune cell-released cytokines and chemokines create a local pro-inflammatory status. In addition, obese AT is characterized by excessive production and disturbed capacity to store lipids, which accumulate ectopically in skeletal muscle. These intramuscular lipids and their derivatives induce mitochondrial dysfunction characterized by impaired β-oxidation capacity and increased reactive oxygen species formation providing lipotoxic environment and insulin resistance as well as enhanced secretion of some pro-inflammatory myokines capable of inducing muscle dysfunction by auto/paracrine manner. In turn, by endocrine manner, these myokines may exacerbate AT inflammation and also support chronic low grade systemic inflammation (inflammaging), overall establishing a detrimental vicious circle maintaining AT and skeletal muscle inflammation, thus triggering and supporting SOB development. Under these circumstances, we believe that AT inflammation dominates over skeletal muscle inflammation. Thus, in essence, it redirects the vector of processes from "sarcopenia→obesity" to "obesity→sarcopenia". We therefore propose that this condition be defined as "obese sarcopenia", to reflect the direction of the pathological pathway.

Effect of exercise training on C reactive protein: a systematic review and meta-analysis of randomised and non-randomised controlled trials

PURPOSE

C-reactive protein (CRP) is a marker of chronic systemic inflammation frequently used in cardiovascular disease risk assessment. The purpose of this meta-analysis was to provide a quantitative estimate of the magnitude of change in CRP following participation in physical exercise interventions.

METHODS

All studies included in the meta-analysis were peer reviewed and published in English. Human participants were assigned to a non-exercise comparison group or exercise training group, with the intervention lasting ≥2 weeks. CRP levels were measured at baseline, during and/or after completion of the exercise training programme. Random-effects models were used to aggregate a mean effect size (ES), 95% CIs and potential moderators.

RESULTS

83 randomised and non-randomised controlled trials met the inclusion criteria and resulted in 143 effects (n=3769). The mean ES of 0.26 (95% CI 0.18 to 0.34, p<0.001) indicated a decrease in CRP following exercise training. A decrease in body mass index (BMI; β=1.20, SE=0.25, p<0.0001) and %Fat (β=0.76, SE=0.21, p=0.0002) were associated with a decrease in CRP, independently accounting for 11.1% and 6.6% of the variation in response, respectively. Exercise training led to a greater reduction in CRP when accompanied by a decrease in BMI (ES=0.38, 95% CI 0.26 to 0.50); however, a significant improvement in CRP occurred in the absence of weight loss (ES=0.19, 95% CI 0.10 to 0.28; both p<0.001).

CONCLUSIONS

These results suggest that engaging in exercise training is associated with a decrease in CRP levels regardless of the age or sex of the individual; however, greater improvements in CRP level occur with a decrease in BMI or %Fat.

Resistance training reduces systolic blood pressure in metabolic syndrome: a systematic review and meta-analysis of randomised controlled trials

Aim

To evaluate the effects of resistance training on metabolic syndrome risk factors through comparison with a control group.

Design

Meta-analysis comparing resistance training interventions with control groups. Two independent reviewers selected the studies and assessed their quality and data. The pooled mean differences between resistance training and the control group were calculated using a fixed-effects model.

Data sources

The MEDLINE, PEDro, EMBASE, SPORTDiscus and The Cochrane Library databases were searched from their earliest records to 10 January 2015.

Eligibility criteria for selecting studies

Randomised controlled trials that compared the effect of resistance training on metabolic syndrome risk factors with a control group were included. All types of resistance training, irrespective of intensity, frequency or duration, were eligible.

Results

Only systolic blood pressure was significantly reduced, by 4.08 mm Hg (95% CI 1.33 to 6.82; p<0.01), following resistance training. The pooled effect showed a reduction of 0.04 mmol/L (95% CI −0.12, 0.21; p>0.05) for fasting plasma glucose, 0.00 (95% CI −0.05, 0.04; p>0.05) for high-density lipoprotein (HDL) cholesterol, 0.03 (95% CI −0.14, 0.20; p>0.05) for triglycerides, 1.39 mm Hg (95% CI −0.19, 2.98; p=0.08) for diastolic blood pressure and 1.09 cm (95% CI −0.12, 2.30; p=0.08) for waist circumference. Inconsistency (I²) for all meta-analysis was 0%.

Conclusions

Resistance training may help reduce systolic blood pressure levels, stroke mortality and mortality from heart disease in people with metabolic syndrome.

Trial registration number

CRD42015016538.

Effect of an acute bout of aerobic exercise on chemerin levels in obese adults

AIMS

Serum chemerin concentrations are elevated in obese individuals and may play a role in type 2 diabetes. Exercise improves insulin sensitivity, which may be related to changes in chemerin. This study explored how an acute bout of aerobic exercise affected chemerin levels in non-diabetic obese adults.

METHODS

Blood samples from 11 obese adults were obtained during two separate conditions: sedentary (SED) and exercise (EX; 60-65% VO2peak). Samples were drawn at baseline, immediately following exercise and hourly for an additional 2h. ANOVA was used to test for differences in chemerin between conditions.

RESULTS

Unadjusted analysis showed no difference in overall change (baseline to 2h post) in chemerin between conditions. During the 2-h post-exercise period, chemerin decreased to 12% below baseline, compared to a 2.5% increase above baseline during that time period on the sedentary day (p=0.06, difference in post-to-2h change between conditions). Controlling for homeostatic model assessment of insulin resistance (HOMA-IR), a significant difference existed between EX and SED in the change in chemerin from baseline to 2-h post (p=0.02). Stratified analyses showed a consistent exercise-induced decrease in chemerin among non-insulin resistant subjects, while chemerin increased during exercise among insulin resistant subjects, and then decreased post-exercise.

CONCLUSION

An acute bout of exercise in obese individuals may elicit a drop in chemerin levels during the post-exercise period, and this response may vary based on insulin resistance.

The influence of a ten-week Nordic walking training-rehabilitation program on the level of lipids in blood in overweight and obese postmenopausal women

[Purpose] The aim of this study was to evaluate the effect of a ten-week Nordic Walking (NW) rehabilitation program on chosen anthropometric parameters and the level of basic lipids in overweight and obese postmenopausal women’s blood. [Subjects and Methods] The subjects were 32 women aged 50–68 (average: 59.7 ± 5.9 years). The study was carried out following a non-randomized model and entailed NW rehabilitation 5 times a week, which lasted for 10 weeks, as well as a low-calorie 1,500 kcal diet. The therapeutic results of the study were measured through changes in anthropometric and biochemical parameters. The results were subjected to a statistical analysis. [Results] After 10 weeks of NW rehabilitation it was observed that participants lost weight and their body mass index dropped. Additionally, whereas levels of total cholesterol, LDL and triglycerides dropped, and the level of HDL increased. [Conclusion] Rehabilitation carried out according to the NW model resulted in statistically significant changes in basic lipids in blood which, considerably increased the percentage of persons who achieved the recommended level of blood lipids. Obese persons were characterised by a smaller rehabilitation weight loss. More intense workouts and cooperation with a dietician are required.

Diet-induced increases in chemerin are attenuated by exercise and mediate the effect of diet on insulin and HOMA-IR

OBJECTIVES

Chemerin concentrations are elevated in obesity and associated with inflammation and insulin resistance. Exercise improves insulin sensitivity, which may be facilitated by changes in chemerin. We explored the effects of chronic exercise on chemerin levels in diet-induced obese mice.

METHODS

We divided 40 mice into 4 groups: high-fat diet/exercise, high-fat diet/sedentary, normal diet/exercise, and normal diet/sedentary. A 9-week dietary intervention was followed by a 12-week exercise intervention (treadmill run: 11 m/min for 30 min, 3×/week). We analyzed blood samples before and after the exercise intervention. We used t-tests and linear regression to examine changes in chemerin, insulin resistance, and inflammatory markers, and associations between changes in chemerin and all other biomarkers.

RESULTS

Chemerin increased significantly across all mice over the 12-week intervention (mean ± SD = 40.7 ± 77.8%, p = 0.01), and this increase was smaller in the exercise versus sedentary mice (27.2 ± 83.9% versus 54.9 ± 70.5%, p = 0.29). The increase among the high-fat diet/exercise mice was ~44% lower than the increase among the high-fat diet/sedentary mice (55.7 ± 54.9% versus 99.8 ± 57.7%, p = 0.12). The high-fat diet mice showed significant increases in insulin (773.5 ± 1286.6%, p < 0.0001) and homeostatic model assessment of insulin resistance (HOMA-IR; 846.5 ± 1723.3%, p < 0.01). Mediation analyses showed that increases in chemerin explained a substantial amount of the diet-induced increases in insulin and HOMA-IR.

CONCLUSION

Chronic exercise may attenuate diet-driven increases in circulating chemerin, and the insulin resistance associated with a high-fat diet may be mediated by diet-induced increases in chemerin.

Positive effect of exercise training at maximal fat oxidation intensity on body composition and lipid metabolism in overweight middle-aged women

The purpose of this study was to test the hypothesis that 10 weeks of supervised exercise training at the maximal fat oxidation (FATmax) intensity would improve important variables of body composition and lipid metabolism in overweight middle-aged women. A longitudinal study design was employed to evaluate the effects of FATmax exercise training. Thirty women (45-59 years old; BMI 28·2 ± 1·8 kg m(-2) ; body fat 38·9 ± 4·1%) were randomly allocated into the Exercise and Control groups, n = 15 in each group. Body composition, FATmax, predicted VO2 max, lipid profile, plasma lipoprotein lipase activity and serum leptin concentration were measured before and after the experimental period. The Exercise group was trained at the individualized FATmax intensity, 5 days per week and 1 h per day for 10 weeks. No diet control was introduced during the experimental period for all participants. Exercise group obtained significant decreases in body mass, BMI, body fat % and abdominal fat mass, as well as the concentrations of triglycerides, serum leptin and blood glucose. The activity of lipoprotein lipase was increased in trained participants. There were no changes in these variables in the Control group. In addition, there was no significant change in daily energy intake for all participants before and after the experimental period. In conclusion, the 10-week FATmax exercise training achieved improvements in body composition and lipid metabolism in overweight middle-aged women. This result suggests FATmax is an effective exercise training intensity for obesity treatment.

Chemerin is a novel biomarker of acute coronary syndrome but not of stable angina pectoris

BACKGROUND

Recent evidence demonstrated that the circulating adipokines were associated with the onset of acute coronary syndrome (ACS) including unstable angina pectoris (UAP) and acute myocardial infarction (AMI). As a novel adipokine, chemerin has been related to atherosclerosis and the presence of coronary artery disease. However, the plasma levels of chemerin in patients with ACS have yet to be investigated.

METHODS

Plasma levels of chemerin and adiponectin were measured by an enzyme-linked immunosorbent assay (ELISA) in 60 patients with stable angina pectoris (SAP), 60 patients with UAP, 60 patients with AMI and 40 control patients. Left ventricular end-diastolic diameter (LVEDD) and left ventricular ejection fraction (LVEF) were measured using a GE ViVid E7 ultrasonography machine, and the severity of coronary stenosis in patients was estimated with a Gensini coronary score following coronary angiography.

RESULTS

Plasma chemerin levels were significantly higher in ACS patients than in the control and SAP groups, while plasma adiponectin levels were significantly lower in ACS patients than the control group. A correlation analysis revealed that plasma chemerin levels were positively correlated with the levels of C-reactive protein (CRP) (r = 0.29, P < 0.01) and LVEDD (r = 0.27, P < 0.01) but negatively correlated with LVEF (r = -0.45, P < 0.01) and that plasma adiponectin levels were positively correlated with LVEF (r = 0.53, P < 0.01) but negatively correlated with CRP (r = -0.33, P < 0.01) and LVEDD (r = -0.30, P < 0.01). Although significant correlations between chemerin, adiponectin and BMI or the Gensini coronary score were found in patients with SAP, neither chemerin nor adiponectin was correlated with BMI and the Gensini coronary score in patients with ACS. Furthermore, both chemerin (OR 1.103, 95% CI 1.065 to 1.142; P = 0.001) and adiponectin (OR 0.871, 95% CI 0.776 to 0.970; P = 0.018) were independently associated with the presence of ACS.

CONCLUSIONS

Chemerin is a novel biomarker of acute coronary syndrome but not of stable angina pectoris.

Effect of lifestyle modification on serum chemerin concentration and its association with insulin sensitivity in overweight and obese adults with type 2 diabetes

OBJECTIVE

Chemerin, a recently identified adipokine, has been linked to adiposity, insulin resistance, metabolic syndrome risk factors and inflammation. Here, we evaluated whether a 12-week lifestyle intervention in overweight and obese adults with type 2 diabetes could significantly affect the average blood glucose and serum chemerin levels over time.

DESIGN

Thirty-five overweight or obese subjects with type 2 diabetes were randomized to receive intensive lifestyle modification including supervised exercise sessions or usual care for 12 weeks. Anthropometric and clinical data were collected before the intervention and after 12 weeks.

RESULTS

Lifestyle intervention induced a significant decrease in HbA1c (-1·0 ± 0·5 vs 0·1 ± 0·6%, P < 0·001), BMI, total body fat content, serum lipocalin-2 and chemerin levels (-8·1 ± 21·6 vs + 8·2 ± 15·9 ng/ml, P = 0·021) and a significant increase in VO2 max after 12 weeks compared to the usual care group. Baseline chemerin levels were positively correlated with the homoeostasis model of assessment of insulin resistance (HOMA-IR), fasting insulin and the high-sensitivity C-reactive protein (hsCRP) and negatively correlated with insulin sensitivity index (ISI). Changes in the chemerin concentration during 12 weeks were independently negatively correlated with changes in ISI and positively correlated with changes in fasting plasma glucose, total cholesterol and lipocalin-2 levels.

CONCLUSIONS

A 12-week intensive lifestyle intervention significantly decreased serum chemerin level compared to usual care. Decrease in serum chemerin level was associated with improved insulin sensitivity, and this may be involved in the beneficial effects of lifestyle intervention in overweight and obese type 2 diabetic patients.

A comparative controlled trial comparing the effects of yoga and walking for overweight and obese adults

Background

Walking and yoga have been independently evaluated for weight control; however, there are very few studies comparing the 2 with randomization.

Material/Methods

The present study compared the effects of 90 minutes/day for 15 days of supervised yoga or supervised walking on: (i) related biochemistry, (ii) anthropometric variables, (iii) body composition, (iv) postural stability, and (v) bilateral hand grip strength in overweight and obese persons. Sixty-eight participants, of whom 5 were overweight (BMI ≥25 kg/m²) and 63 were obese (BMI ≥30 kg/m²; group mean age ±S.D., 36.4±11.2 years; 35 females), were randomized as 2 groups – (i) a yoga group and (ii) a walking group – given the same diet.

Results

All differences were pre-post changes within each group. Both groups showed a significant (p<0.05; repeated measures ANOVA, post-hoc analyses) decrease in: BMI, waist circumference, hip circumference, lean mass, body water, and total cholesterol. The yoga group increased serum leptin (p<0.01) and decreased LDL cholesterol (p<0.05). The walking group decreased serum adiponectin (p<0.05) and triglycerides (p<0.05).

Conclusions

Both yoga and walking improved anthropometric variables and serum lipid profile in overweight and obese persons. The possible implications are discussed.

Circulating chemerin decreases in response to a combined strength and endurance training

Chemerin is an adipokine that may mediate the link between obesity, inflammation, insulin resistance, type 2 diabetes mellitus, and cardiovascular disease. In this study, we examined the association between chemerin and various cardiometabolic risk factors in cross-sectional setting and tested the hypothesis that a 6-month combined exercise program decreases serum chemerin in overweight or obese, non-diabetic individuals. Serum chemerin concentration was measured in a cross-sectional analysis including 98 individuals with a wide range of age and body mass index (BMI). In addition, chemerin was measured in 79 sedentary, overweight or obese, non-diabetic individuals who completed a 6-month combined endurance and resistance exercise program (CEP, n = 51) or served as controls (C, n = 28). Chemerin was significantly associated with total cholesterol (p = 0.04), triglycerides (p < 0.001), fasting insulin (p < 0.001), homeostasis model assessment of insulin resistance (HOMA-IR, p < 0.001), systolic blood pressure (p = 0.04), highly sensitive C-reactive protein (p = 0.03), leucocytes count (p = 0.047), and leptin (p = 0.008) independently of age and BMI. In multiple regression analysis, chemerin was an independent determinant of HOMA-IR. As a result of the 6-month training program, serum chemerin decreased significantly in CEP group (-13.8 ± 13.2 ng/ml, p < 0.001). A significant association between the changes in chemerin and improved HOMA-IR were found even after adjustment for changes in waist circumference. Among non-diabetic individuals serum chemerin was associated with various cardiometabolic risk factors independently of BMI. In addition, the 6-month combined strength and endurance training program led to a significant reduction in circulating chemerin levels in overweight or obese individuals.

Exercise-induced lowering of chemerin is associated with reduced cardiometabolic risk and glucose-stimulated insulin secretion in older adults

OBJECTIVE

To determine the effect of exercise on chemerin in relation to changes in fat loss, insulin action, and dyslipidemia in older adults.

PARTICIPANTS

Thirty older (65.9±0.9yr) obese adults (BMI:34.5±0.7kg/m2).

SETTING

Single-center, Cleveland Clinic.

DESIGN

Prospective clinical trial.

INTERVENTION

Twelve-weeks of exercise training (60minutes/day, 5day/week at ~85% HRmax). Subjects were instructed to maintain habitual nutrient intake.

MEASUREMENTS

Plasma chemerin was analyzed using an enzyme-linked immunosorbent assay. Peripheral and hepatic insulin sensitivity was assessed using a euglycemic-hyperinsulinic clamp with glucose kinetics. First-phase and total glucose-stimulated insulin secretion (GSIS) was calculated from an oral glucose tolerance test. Fasting blood lipids (cholesterol, triglycerides), total/visceral fat (dual-x-ray absorptiometry and computerized tomography) and cardiorespiratory fitness (treadmill test) were also tested pre and post intervention.

RESULTS

Exercise increased fitness and reduced total/visceral fat, blood lipids, and first-phase GSIS (P<0.05). Training also increased peripheral insulin sensitivity and lowered basal/insulin-related hepatic glucose production (P<0.01). The intervention reduced chemerin (87.1±6.0 vs. 78.1±5.8ng/ml; P=0.02), and the reduction correlated with decreased visceral fat (r=0.50, P=0.009), total body fat (r=0.42, P=0.02), cholesterol (r=0.38, P=0.04), triglycerides (r=0.36, P=0.05), and first-phase and total GSIS (r=0.39, P=0.03 and r=0.43, P=0.02, respectively).

CONCLUSIONS

Lower chemerin appears to be an important hormone involved in cardiometabolic risk and GSIS reduction following exercise in older adults.

12 weeks' aerobic and resistance training without dietary intervention did not influence oxidative stress but aerobic training decreased atherogenic index in middle-aged men with impaired glucose regulation

Our aim was to determine whether 12 weeks' aerobic Nordic walking (NW) or resistance exercise training (RT) without diet-induced weight loss could decrease oxidative stress and atherogenic index of plasma (AIP), prevalence of metabolic syndrome (MetS) and MetS score in middle-aged men with impaired glucose regulation (IGR) (n=144. 54.5 ± 6.5 years). In addition, we compared effects of intervention between overweight and obese subgroups. Prevalence of MetS and AIP index decreased only in NW group and MetS score in both NW and RT groups but not in control group. The changes in AIP index correlated inversely with changes in plasma antioxidant capacity. The change in AIP index remained a significant independent predictor of the changes in MetS score after the model was adjusted for age, BMI and volume of exercise (MET h/week) in NW group. There were no changes in the other measured markers of oxidative stress and related cytokines (e.g. osteopontin and osteoprotegerin) in any of the groups. Nordic walking decreased prevalence of MetS and MetS score. Improved lipid profile remained a predictor of decreased MetS score only in NW group and it seems that Nordic walking has more beneficial effects on cardiovascular disease risks than RT training.