Effects of sprint interval or combined aerobic and resistance training on myokines in overweight women with type 2 diabetes: A randomized controlled trial

The effects of exercise on FGF21 in adults: a systematic review and meta-analysis

Background

Fibroblast growth factor 21 (FGF21) is a key hormone factor that regulates glucose and lipid homeostasis. Exercise may regulate its effects and affect disease states. Therefore, we sought to determine how exercise affects FGF21 concentrations in adults.

Methods

The review was registered in the International Prospective Systematic Review (PROSPERO, CRD42023471163). The Cochrane Library, PubMed, and Web of Science databases were searched for studies through July 2023. Studies that assessed the effects of exercise training on FGF21 concentration in adults were included. The random effect model, data with standardized mean difference (SMD), and 95% confidence intervals (CI) were used to evaluate the pooled effect size of exercise training on FGF21. The risk of heterogeneity and bias were evaluated. A total of 12 studies involving 401 participants were included.

Results

The total effect size was 0.3 (95% CI [-0.3-0.89], p = 0.33) when comparing participants who exercised to those who were sedentary. However, subgroup analysis indicated that concurrent exercise and a duration ≥10 weeks significantly decreased FGF21 concentrations with an effect size of -0.38 (95% CI [-0.74--0.01], p < 0.05) and -0.38 (95% CI [-0.63--0.13], p < 0.01), respectively.

Conclusion

Concurrent exercise and longer duration may be more efficient way to decrease FGF21 concentrations in adults with metabolic disorder.

Inhibition of SPARC signal by aerobic exercise to ameliorate atherosclerosis

BACKGROUND AND AIMS

Inflammation and atherosclerosis (AS) are closely associated to Secreted Protein Acidic and Rich in Cysteine (SPARC) and its related factors. This study attempted to define the role and the potential mechanism of SPARC and its related factors in ameliorating hyperlipidemia and AS by aerobic exercise intervention.

METHODS

The AS rat model was established with a high-fat diet plus vitamin D3 intraperitoneal injection. Treadmill exercises training (5 days/week at 14 m/min for 60 min/day) for 6 weeks was carried out for AS rat intervention method. Western blotting and qRT-PCR were used to analyze the mRNA and protein expression of SPARC and its related factors, respectively. H&E staining was applied to evaluate the morphological changes and inflammation damage. Von Kossa staining was used to measure the degree of vascular calcification. Fluorescence immunohistochemistry staining was used to detect the expression and distribution of SPARC signal molecules.

RESULTS

SPARC was highly expressed and co-localization with the smooth muscle marker α-SMC in the AS rat. And its downstream factors, NF-κB, Caspase-1, IL-1β and IL-18 were upregulated (P < 0.05 or P < 0.01), FNDC5 expression was downregulated in AS rat model. However, slight declined body weight, delayed AS progression, decreased hyperlipidemia and favorable morphology of skeletal muscle and blood vessels have been detected in AS rat with aerobic exercise intervention. Moreover, the expression of SPARC and its downstream factors were decreased (P < 0.05 or P < 0.01), while elevated the expression of FNDC5 (P < 0.01) was observed after aerobic exercise intervention.

CONCLUSIONS

This study suggested that aerobic exercise ameliorated hyperlipidemia and AS by effectively inhibiting SPARC signal, and vascular smooth muscle cells may contribute greatly to the protection of AS.

Exploring exercise-driven exerkines: unraveling the regulation of metabolism and inflammation

Exercise has many beneficial effects that provide health and metabolic benefits. Signaling molecules are released from organs and tissues in response to exercise stimuli and are widely termed exerkines, which exert influence on a multitude of intricate multi-tissue processes, such as muscle, adipose tissue, pancreas, liver, cardiovascular tissue, kidney, and bone. For the metabolic effect, exerkines regulate the metabolic homeostasis of organisms by increasing glucose uptake and improving fat synthesis. For the anti-inflammatory effect, exerkines positively influence various chronic inflammation-related diseases, such as type 2 diabetes and atherosclerosis. This review highlights the prospective contribution of exerkines in regulating metabolism, augmenting the anti-inflammatory effects, and providing additional advantages associated with exercise. Moreover, a comprehensive overview and analysis of recent advancements are provided in this review, in addition to predicting future applications used as a potential biomarker or therapeutic target to benefit patients with chronic diseases.

Aerobic training with moderate or high doses of vitamin D improve liver enzymes, LXRα and PGC-1α levels in rats with T2DM

Dysregulation of key transcription factors involved in hepatic energy metabolism, such as peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) and liver X receptor alpha (LXRα), has been observed in T2DM. The present study aims to investigate the effects of aerobic training and vitamin D supplementation on liver enzyme levels and the levels of PGC-1α and LXRα proteins in hepatocytes, in a rat model of T2DM. The study involved 56 male Wistar rats, divided into two groups: one was non-diabetic and acted as a control group (n = 8), and the other had induced diabetes (n = 48). The diabetic rats were then split into six subgroups: two groups received high or moderate doses of vitamin D and aerobic training (D + AT + HD and D + AT + MD); two groups received high or moderate doses of vitamin D alone (D + HD and D + MD); one group underwent aerobic training with vehicle (sesame oil; D + AT + oil), and one group was a diabetic control receiving only sesame oil (oil-receiving). The D + AT + HD and D + HD groups received 10,000 IU of vitamin D, while the D + AT + MD and D + MD groups received 5000 IU of vitamin D once a week by injection. The D + AT + oil group and the sham group received sesame oil. After eight weeks of treatment, body weight, BMI, food intake, serum insulin, glucose, 25-hydroxyvitamin D, ALT, AST, and visceral fat were measured. The levels of PGC-1α and LXRα proteins in the liver was assessed by western blotting. Statistical analysis was performed using the paired t-test, one-way analysis of variance (ANOVA), and the Tukey post hoc test at a significance level of P < 0.05. Body weight, food intake, and BMI decreased significantly in the D + AT + HD, D + AT + MD, D + AT + oil, D + HD, and D + MD groups with the highest reduction being observed in body weight and BMI in the D + AT + HD group. The D + AT + HD group exhibited the lowest levels of insulin, glucose, and HOMA-IR while the D + C group exhibited the highest levels among the diabetic groups. The D + AT + HD and D + AT + MD groups had lower levels of ALT and AST enzymes compared to the other groups with no significant difference between D + AT + HD and D + AT + MD. D + AT + HD (p = 0.001), D + AT + MD (p = 0.001), D + HD (p = 0.023), D + MD (p = 0.029), and D + AT + oil (p = 0.011) upregulated LXRα compared to D + C. Among these groups, D + AT + HD exhibited a more profound upregulation of LXRα than D + AT + MD, D + AT + oil, D + HD, and D + MD (p = 0.005; p = 0.002, p = 0.001, and p = 0.001, respectively). Similarly, D + AT + HD showed a more notable upregulation of PGC-1α compared to D + AT + oil, D + HD, and D + MD (p = 0.002; p = 0.001, and p = 0.001, respectively). Pearson correlation tests showed significant and negative correlations between serum 25-hydroxyvitamin levels and both visceral fat (r = - 0.365; p = 0.005) and HOMA-IR (r = - 0.118; p = 0.009); while positive and significant correlations between the liver-to-bodyweight ratio with both ALT and AST enzymes and also between QUICKI levels with LXRα (r = 0.578; p = 0.001) and PGC-1α (r = 0.628; p = 0.001). Combined administration of aerobic training and vitamin D supplementation potentially improves liver enzymes in type-2 diabetic rats that were simultaneous with upregulating the levels of PGC-1α and LXRα proteins in hepatocytes. These improvements were more significant when combining exercise with high-dose vitamin D supplementation. This study highlights the potential of this combination therapy as a new diabetes treatment strategy.

Effect of combined aerobic-resistance training and subsequent detraining on brain-derived neurotrophic factor (BDNF) and depression in women with type 2 diabetes mellitus: A randomized controlled trial

AIMS

In this study, we assessed the effects of a 12-week combined aerobic-resistance training and subsequent detraining on Beck Depression Inventory (BDI) score and mediating role of BDNF and also investigated whether exercise-induced alterations are maintained following a short period of detraining in women with type 2 diabetes (T2D).

MATERIALS AND METHODS

Thirty-four women with T2D were randomly assigned to experimental or control group (age: 60.6 ± 6.3, body mass index (BMI): 30.2 ± 1.3 kg/m2 , HbA1c: 8.09 ± 0.73%). The exercise training comprised of combined aerobic-resistance programme (50%-70% heart rate reserve for aerobic exercise, and 50%-70% 1 repetition maximum for resistance exercise, respectively) performed three sessions per week over 12 weeks. The intervention period was followed by an 8-week detraining period. Data were collected at baseline and also following exercise intervention and detraining. Data were analysed by linear mixed model at p < 0.05.

RESULTS

After 12 weeks of combined exercise training and 8 weeks of detraining, there was a significant difference in BDNF (0.08; 95% confidence interval [CI] = 0.07-0.10; p = 0.001), fasting blood glucose (FBG) (-45.41; CI = -50.83, -39.98; p = 0.001), insulin (-6.47; CI = -7.04, -5.9; p = 0.001), HOMA-IR (-3.76; CI = -4.07, -3.45; p = 0.001) and BDI score (-17.17; CI = -20.29, -14.05; p = 0.001) between the experimental and control group. Multiple mediation analysis indicated that BDNF seems to have a mediating role in exercise-induced improvement of depression (p = 0.04). After the detraining period, BDI score remained unchanged and it showed a significant increase compared to before the start of training (p = 0.001).

CONCLUSIONS

It may be concluded that exercise training improves depression that is likely to be explained by increased BDNF concentration in TD2. In spite of decreased BDNF concentration following an 8-week detraining, depression score was maintained.

Is low-volume high-intensity interval training a time-efficient strategy to improve cardiometabolic health and body composition? A meta-analysis

The present meta-analysis aimed to assess the effects of low-volume high-intensity interval training (LV-HIIT; i.e., ≤5 min high-intensity exercise within a ≤15 min session) on cardiometabolic health and body composition. A systematic search was performed in accordance with PRISMA guidelines to assess the effect of LV-HIIT on cardiometabolic health and body composition. Twenty-one studies (moderate to high quality) with a total of 849 participants were included in this meta-analysis. LV-HIIT increased cardiorespiratory fitness (CRF, SMD = 1.19 [0.87, 1.50]) while lowering systolic blood pressure (SMD = -1.44 [-1.68, -1.20]), diastolic blood pressure (SMD = -1.51 [-1.75, -1.27]), mean arterial pressure (SMD = -1.55 [-1.80, -1.30]), MetS z-score (SMD = -0.76 [-1.02, -0.49]), fat mass (kg) (SMD = -0.22 [-0.44, 0.00]), fat mass (%) (SMD = -0.22 [-0.41, -0.02]), and waist circumference (SMD = -0.53 [-0.75, -0.31]) compared to untrained control (CONTROL). Despite a total time-commitment of LV-HIIT of only 14%-47% and 45%-94% compared to moderate-intensity continuous training and HV-HIIT, respectively, there were no statistically significant differences observed for any outcomes in comparisons between LV-HIIT and moderate-intensity continuous training (MICT) or high-volume HIIT. Significant inverse dose-responses were observed between the change in CRF with LV-HIIT and sprint repetitions (β = -0.52 [-0.76, -0.28]), high-intensity duration (β = -0.21 [-0.39, -0.02]), and total duration (β = -0.19 [-0.36, -0.02]), while higher intensity significantly improved CRF gains. LV-HIIT can improve cardiometabolic health and body composition and represent a time-efficient alternative to MICT and HV-HIIT. Performing LV-HIIT at a higher intensity drives higher CRF gains. More repetitions, longer time at high intensity, and total session duration did not augment gains in CRF.

The effects of 12 weeks of high-intensity interval training and moderate-intensity continuous training on FGF21, irisin, and myostatin in men with type 2 diabetes mellitus

This study investigated the influence of a 12-week high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on irisin, fibroblast growth factor 21 (FGF21), and myostatin (MSTN) among men with type 2 diabetes mellitus (T2DM). Forty-five adult men with T2DM were randomly selected and assigned to receive and perform HIIT (4 × 4 min at 85-95% HRmax with three min of active rest at 50-60% HRmax in between) and MICT (walking/running continuously for 47 min at 60-70% HRmax) three sessions per week for 12 weeks, or to act as a non-exercise control (CON) group. The subjects' blood samples were collected at baseline and 48 hours after the last intervention session. Our research revealed that both interventions resulted in similar decreases in FGF21 and MSTN when compared to the CON (p < .01). However, only the HIIT group showed a significant increase in irisin (p < .01) compared to the CON. Further, improvements in insulin resistance, body composition, and VO2 peak were noted in both intervention groups compared with those of the CON group (p < .01). It seems that while either aerobic exercise strategy could be seen as a therapy for men with T2DM, HIIT had a more advantageous effect on the irisin response.

Interleukin-15 responses to acute and chronic exercise in adults: a systematic review and meta-analysis

Purpose

Interlukin-15 (IL-15) is an inflammatory cytokine that plays a vital role in immunology and obesity-associated metabolic syndrome. We performed this systematic review and meta-analysis to investigate whether exercise promotes circulating IL-15 concentrations in adults.

Methods

We searched PubMed, Web of Science, and Scopus from inception to May, 2023 and identified original studies that investigated the effectiveness of acute and/or chronic exercise on serum/plasma IL-15 levels in adults. Standardized mean differences (SMD) and 95% confidence intervals (CI) were calculated using random effect models. Subgroup analyses were performed based on type of exercise, and training status, health status and body mass indexes (BMI) of participants.

Results

Fifteen studies involving 411 participants and 12 studies involving 899 participants were included in the acute and chronic exercise analyses, respectively. Our findings showed that acute exercise increased circulating IL-15 concentrations immediately after exercise compared with baseline [SMD=0.90 (95% CI: 0.47 to 1.32), p=0.001], regardless of exercise type and participants' training status. Similarly, acute exercise was also associated with increased IL-15 concentrations even one-hour after exercise [SMD=0.50 (95% CI: 0.00 to 0.99), p=0.04]. Nevertheless, chronic exercise did not have a significant effect on IL-15 concentrations [SMD=0.40 (95% CI: -0.08 to 0.88), p=0.10].

Conclusion

Our results confirm that acute exercise is effective in increasing the IL-15 concentrations immediately and one-hour after exercise intervention, and thereby playing a potential role in improving metabolism in adults.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=445634, identifier CRD42023445634.

Rates of compliance and adherence to high-intensity interval training: a systematic review and Meta-analyses

BACKGROUND

To determine rates of compliance (i.e., supervised intervention attendance) and adherence (i.e., unsupervised physical activity completion) to high-intensity interval training (HIIT) among insufficiently active adults and adults with a medical condition, and determine whether compliance and adherence rates were different between HIIT and moderate-intensity continuous training (MICT).

METHODS

Articles on adults in a HIIT intervention and who were either insufficiently active or had a medical condition were included. MEDLINE, EMBASE, PsychINFO, SPORTDiscus, CINAHL, and Web of Science were searched. Article screening and data extraction were completed by two independent reviewers. Risk of bias was assessed using RoB 2.0 or ROBINS-I. Meta-analyses were conducted to discern differences in compliance and adherence between HIIT vs. MICT. Sensitivity analyses, publication bias, sub-group analyses, and quality appraisal were conducted for each meta-analysis.

RESULTS

One hundred eighty-eight unique studies were included (n = 8928 participants). Compliance to HIIT interventions averaged 89.4% (SD:11.8%), while adherence to HIIT averaged 63% (SD: 21.1%). Compliance and adherence to MICT averaged 92.5% (SD:10.6%) and 68.2% (SD:16.2%), respectively. Based on 65 studies included in the meta-analysis, compliance rates were not different between supervised HIIT and MICT interventions [Hedge's g = 0.015 (95%CI: - 0.088-0.118), p = .78]. Results were robust and low risk of publication bias was detected. No differences were detected based on sub-group analyses comparing medical conditions or risk of bias of studies. Quality of the evidence was rated as moderate over concerns in the directness of the evidence. Based on 10 studies, adherence rates were not different between unsupervised HIIT and MICT interventions [Hedge's g = - 0.313 (95%CI: - 0.681-0.056), p = .096]. Sub-group analysis points to differences in adherence rates dependent on the method of outcome measurement. Adherence results should be interpreted with caution due to very low quality of evidence.

CONCLUSIONS

Compliance to HIIT and MICT was high among insufficiently active adults and adults with a medical condition. Adherence to HIIT and MICT was relatively moderate, although there was high heterogeneity and very low quality of evidence. Further research should take into consideration exercise protocols employed, methods of outcome measurement, and measurement timepoints.

REGISTRATION

This review was registered in the PROSPERO database and given the identifier CRD42019103313.

Effects of exercise training parameters on cardiorespiratory fitness of individuals with type 2 diabetes mellitus: a systematic review and meta-analysis

Purpose

To assess the effects of exercise training parameters on cardiorespiratory fitness of individuals with type 2 diabetes mellitus (T2DM).

Methods

This systematic review was registered on PROSPERO (CRD42020210470). Searches were performed on PubMed, PEDro EMBASE, MEDLINE (Ovid), LILACS, PsycINFO, SCIELO, CINAHL, and Cochrane Library. The primary outcome was cardiorespiratory fitness, defined as maximal oxygen uptake (VO2max) during a maximal or submaximal exercise test. Two independent reviewers extracted data and assessed the risk of bias. Data were pooled using a random effects model and expressed as mean difference (MD) and 95% confidence interval (95%CI). Heterogeneity (I2) was assessed using Cochran's Q test. The risk of bias and quality of evidence was assessed using the Cochrane risk of bias tool and GRADE.

Results

Twenty-two studies comparing exercise and control groups were included. The risk of bias indicated some concerns in most studies, and the quality of evidence was rated very low. Interventions with moderate (MD = 1.91, 95%CI = .58 to 3.34) and progressive exercise intensity (MD = 2.70, 95%CI = 2.43 to 2.96) and volume (MD = 1.72, 95%CI = .59 to 2.85) showed greater improvements in VO2max.

Conclusions

Protocols that progressively increased exercise training parameters improved the cardiorespiratory fitness response. Progressive exercise might be more suitable for individuals with T2DM. Our conclusion may be limited due to the very low quality of evidence.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-023-01205-5.

Exercise Is Medicine for Nonalcoholic Fatty Liver Disease: Exploration of Putative Mechanisms

Exercise remains a key component of nonalcoholic fatty liver disease (NAFLD) treatment. The mechanisms that underpin improvements in NAFLD remain the focus of much exploration in our attempt to better understand how exercise benefits patients with NAFLD. In this review, we summarize the available scientific literature in terms of mechanistic studies which explore the role of exercise training in modulating fatty acid metabolism, reducing hepatic inflammation, and improving liver fibrosis. This review highlights that beyond simple energy expenditure, the activation of key receptors and pathways may influence the degree of NAFLD-related improvements with some pathways being sensitive to exercise type, intensity, and volume. Importantly, each therapeutic target of exercise training in this review is also the focus of previous or ongoing drug development studies in patients with nonalcoholic steatohepatitis (NASH), and even when a regulatory-agency-approved drug comes to market, exercise will likely remain an integral component in the clinical management of patients with NAFLD and NASH.

Intermittent high-intensity exercise for pre- to established hypertension: A systematic review and meta-analysis

OBJECTIVE

To determine the impact of intermittent high-intensity exercise training ([IHIE], including high-intensity interval training [HIIT] and recreational team sports [RTS]) on systolic (SBP) and diastolic blood pressure (DBP) in adults with pre- to established arterial hypertension.

DATA SOURCES

MEDLINE, Cochrane Library, Embase, and SPORTDiscus.

ELIGIBILITY CRITERIA

Randomized controlled trials (RCTs) comparing the impact of IHIE on BP versus a non-exercise control.

DATA COLLECTION AND ANALYSIS

Two authors independently conducted all procedures. Mean differences were calculated using random-effects model. The certainty of the evidence was assessed with GRADE.

RESULTS

Twenty-seven RCTs (18 HIIT and 9 RTS) were analyzed, with median duration of 12 weeks. Participants' (n = 946) median age was 46 years. Overall, IHIE decreased SBP (-3.29 mmHg; 95% CI: -5.19, -1.39) and DBP (-2.62 mmHg; 95% CI: -3.79, -1.44) compared to the control group. IHIE elicited higher decreases in office SBP and DBP of hypertensive subjects (SBP: -7.13 mmHg, [95% CI: -10.12, -4.15]; DBP: -5.81 mmHg, [95% CI: -7.94, -3.69]) than pre-hypertensive (SBP: -2.14 mmHg, [95% CI: -4.36, -0.08]; DBP: -1.83 mmHg, [95% CI: -2.99, -0.67]). No significant differences were found between HIIT (SBP: -2.12 mmHg, [95% CI: -4.78, -0.54]; DBP: -1.89 mmHg, [95% CI: -3.32, -0.48]) and RTS (SBP: -4.18 mmHg, [95% CI: -7.19, -2.43]; DBP: -4.04 mmHg, [95% CI: -6.00, -2.09]). These findings present low/very low certainty of evidence. No adverse cardiovascular events were reported.

CONCLUSIONS

IHIE appears to be safe and to promote substantial decreases in BP, particularly in patients with hypertension. However, the certainty of evidence was low/very low.

PROTOCOL

CRD42020163575.

The effect of two concurrent exercise modalities on serum concentrations of FGF21, irisin, follistatin, and myostatin in men with type 2 diabetes mellitus

This study investigated the effect of concurrent training (CT) sequences on fibroblast growth factor 21 (FGF21), irisin, myostatin (MSTN), and follistatin (FST) among adults with type 2 diabetes mellitus (T2DM). Fifty-one diabetic men were randomly selected and assigned to concurrent aerobic-resistance (A-R) training and concurrent resistance-aerobic (R-A) training, and non-exercise control (CON) groups. The training protocols consisted of three sessions per week for 12 weeks. The A-R and R-A groups received the same CT protocols and performed with different sequences. The subjects' blood samples were obtained at baseline and 48 hours after the last session of the intervention. The results showed that the concentration of FGF21 did not change significantly after the 12 weeks of CT with different sequences (p > .05, η² = 0.123), but the serum concentration of irisin (A-R = 2.93 μg.L^-1 (95% CI = 1.45-4.42, d = -0.57) and R-A = 3.31 μg.L^-1 (95% CI = 1.13-5.49, d = -0.68)) and FST (A-R = 4.96 ng.mL^-1 (95% CI = 3.41-6.5, d = -0.39) and R-A = 4.19 ng.mL^-1 (95% CI = 2.82-5.56, d = -0.55)) significantly increased while the serum MSTN concentration (A-R = 152.32 ng.L^-1 (95% CI = 61.83-242.82, d = 1.31) and R-A = 173 ng.L^-1 (95% CI = 35.89-227.5, d = 0.83)) of both A-R and R-A groups mainly decreased (p < .01). There was no significant difference between A-R and R-A groups' irisin, FST, and MSTN concentration (p > .05), though the CT improved the body compositions, strength, and peak oxygen uptake in both groups (p < .01). Regardless of the CT sequences, it was found that CT acted as a therapeutic modality of training for T2DM patients by increasing their irisin and FST and decreasing their MSTN concentrations.

Immunomodulatory Function of Interleukin-15 and Its Role in Exercise, Immunotherapy, and Cancer Outcomes

Exercise has been shown to improve physical and psychosocial outcomes for people across the cancer care continuum. A proposed mechanism underpinning the relationship between exercise and cancer outcomes is exercise-induced immunomodulation via secretion of anti-inflammatory myokines from skeletal muscle tissue. Myokines have the potential to impair cancer growth through modulation of natural killer (NK) cells and CD8+ T cells while improving the effectiveness of cancer therapies. Interleukin-15 (IL-15), one of the most abundant myokines found in skeletal muscle, has a key immunoregulatory role in supporting the proliferation and maturation of T cells and NK cells, which have a key role in the host's immune response to cancer. Furthermore, IL-15 is being explored clinically as an immunotherapy agent with doses similar to the IL-15 concentrations released by skeletal muscle during exercise. Here we review the role of IL-15 within the immune system, examine how IL-15 is produced as a myokine during exercise, and how it may improve outcomes for people with cancer, specifically as an adjuvant or neoadjuvant to immunotherapy. We summarize the available evidence showing changes in IL-15 in response to both acute exercise and training, and the results are inconsistent; higher quality research is needed to advance the understanding of how exercise-mediated increases in IL-15 potentially benefit those who are being treated for, or who have had, cancer.

The effects of a 20-week exercise program on blood-circulating biomarkers related to brain health in overweight or obese children: The ActiveBrains project

BACKGROUND

Emerging research supports the idea that exercise positively affects neurodevelopment. However, the mechanisms linking exercise with brain health are largely unknown. We aimed to investigate the effect of exercise on (a) blood biomarkers selected based on previous evidence (brain-derived neurotrophic factor, β-hydroxybutyrate (BHB), cathepsin B (CTSB), kynurenine, fibroblast growth factor 21 (FGF21), soluble vascular cell adhesion molecule-1 (sVCAM-1)); and (b) a panel of 92 neurology-related proteins (discovery analysis). We also investigated whether changes in these biomarkers mediate the effects of exercise on brain health (hippocampal structure and function, cognitive performance, and mental health).

METHODS

We randomized 81 overweight/obese children (10.1 ± 1.1 years, 41% girls) into 2 groups: either 20 weeks of aerobic plus resistance exercise or control. Candidate biomarkers were assessed using enzyme-linked immunosorbent assay (ELISA) for kynurenine, FGF21, and CTSB; colorimetry for β-hydroxybutyrate; and XMap for brain-derived neurotrophic factor and soluble vascular cell adhesion molecule-1. The 92 neurology-related proteins were analyzed by an antibody-based proteomic analysis.

RESULTS

Our intervention had no significant effect on candidate biomarkers (all p > 0.05). In the discovery analysis, a reduction in circulating macrophage scavenger receptor type-I was observed (standardized differences between groups = -0.3, p = 0.001). This effect was validated using ELISA methods (standardized difference = -0.3, p = 0.01). None of the biomarkers mediated the effects of exercise on brain health.

CONCLUSIONS

Our study does not support a chronic effect of exercise on candidate biomarkers. We observed that while chronic exercise reduced the levels of macrophage scavenger receptor type-I, it did not mediate the effects of exercise on brain health. Future studies should explore the implications of this novel biomarker for overall health.

Exercise training-induced changes in exerkine concentrations may be relevant to the metabolic control of type 2 diabetes mellitus patients: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

This study investigates the effects of exercise training on exerkines in patients with type 2 diabetes mellitus to determine the optimal exercise prescription.

METHODS

A systematic search for relevant studies was performed in 3 databases. Randomized controlled trials investigating the effects of exercise training on at least one of the following exerkines were included: adiponectin, apelin, brain-derived neurotrophic factor, fetuin-A, fibroblast growth factor-21, follistatin, ghrelin, interleukin (IL)-6, IL-8, IL-10, IL-15, IL-18, leptin, myostatin, omentin, resistin, retinol-binding protein 4, tumor necrosis factor-α, and visfatin.

RESULTS

Forty randomized controlled trials were selected for data extraction (n = 2160). Exercise training induces changes in adiponectin, fetuin-A, fibroblast growth factor-21, IL-6, IL-10, leptin, resistin, and tumor necrosis factor-α levels but has no significant effects on apelin, IL-18, and ghrelin compared to controls. Physical exercise training favored large and positive changes in pooled exerkines (i.e., an overall effect size calculated from several exerkines) (Hedge's g = 1.02, 95% confidence interval (95%CI): 0.76-1.28), which in turn were related to changes in glycated hemoglobin (mean difference (MD) = -0.81%, 95%CI: -0.95% to -0.67%), fasting glucose (MD = -23.43 mg/dL, 95%CI: -30.07 mg/dL to -16.80 mg/dL), waist circumference (MD = -3.04 cm, 95%CI: -4.02 cm to -2.07 cm), and body mass (MD = -1.93 kg, 95%CI: -2.00 kg to -1.86 kg). Slightly stronger effects were observed with aerobic, resistance, or high-intensity interval protocols at moderate- to vigorous-intensity and with programs longer than 24 weeks that comprise at least 3 sessions per week and more than 60 min per session.

CONCLUSION

Exercise training represents an anti-inflammatory therapy and metabolism-improving strategy with minimal side effects for patients with type 2 diabetes mellitus.

Exercise modalities for type 2 diabetes: A systematic review and network meta-analysis of randomized trials

AIMS

We aimed to determine the effects of different exercise modalities in patients with type 2 diabetes mellitus (T2DM).

METHODS

We searched PubMed, Embase, and the Cochrane Library from their inception until July 2020 to identify randomised controlled trials (RCTs) on exercise in adults with T2DM. Paired reviewers independently performed study selection, data extraction, and risk of bias assessment. The certainty of the evidence was assessed using the Confidence in Network Meta-Analysis (CINeMA) framework.

RESULTS

A total of 106 RCTs that enroled eight exercise modalities with 7438 patients were included. Six exercise modalities, except unsupervised aerobic/resistance exercise, significantly reduced glycosylated haemoglobin (HbA1c), with mean differences (MDs) ranging from 0.71 (95% confidence interval [CI]: 0.34-1.08) to 0.34 (95% CI: 0.17-0.52), low to high certainty, in comparison with no exercise. The evidence of low to moderate certainty showed that supervised aerobic/resistance exercise improved glycaemic control, body weight, blood pressure, and blood lipid profiles compared with no exercise. Flexibility exercise may be associated with glycaemic control (HbA1c: MD = 0.71, 95% CI: 0.34-1.08); fasting plasma glucose (MD = 1.48, 95% CI: 0.78-2.17), and weight loss (MD = 1.80, 95% CI: 0.85-2.75) compared with controls, but not blood pressure and lipid profiles. Balance exercise showed the largest benefit in improving total cholesterol (MD = 52.81, 95% CI: 28.47-77.16) and low certainty. We found no significant differences between exercises and the triacylglycerol (TG) level.

CONCLUSIONS

Overall, our network meta-analyses support the recommendation for exercise in patients with T2DM, especially supervised exercises. Limited evidence supports the benefits of flexibility and balance exercises. The effectiveness of exercise modalities for TG reduction remains unclear.

Effects of Exercise on Circulating Muscle-related Cytokines in Adults with Type 2 Diabetes and/or Obesity

BACKGROUND

Skeletal muscle is an endocrine organ that plays an important role in metabolic health by secreting a variety of myokines. Recent studies have shown that exercise significantly decreases interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in patients with type 2 diabetes (T2D). This paper explores the effect of chronic exercise on myokines in patients with T2D and/or obesity.

METHODS

The author searched for relevant English-language articles in PubMed. A total of 14 randomized controlled studies were found to be eligible for this short review.

RESULTS

It has been observed that chronic exercise does not change brain-derived neurotrophic factor (BDNF), irisin, and secreted protein acidic and rich in cysteine levels, whereas it decreases TNF-α levels in patients with T2D. Combined aerobic exercise (AE) and resistance training (RT) or sprint interval training increase insulin-like growth factor 1 (IGF-1) levels and decrease IL-6 and IL-15 levels in patients with T2D. Combined AE and RT may also increase IL-15 levels in obese individuals. In addition, RT alone may increase BDNF, IGF-1, and IL-7 levels in overweight individuals. However, AE alone does not change circulating myokine levels in patients with T2D, while it may increase myonectin levels in obese individuals.

CONCLUSION

This short review demonstrated that exercise appears to have favorable effects on some myokines in patients with T2D and/or obesity. However, it remains inconclusive due to the heterogeneity in subject characteristics and exercise modalities.

Changes in irisin, inflammatory cytokines and aerobic capacity in response to three weeks of supervised sprint interval training in older men

BACKGROUND

This study investigated the effects of supervised short-term sprint interval training (SIT) on circulating irisin, interleukin (IL)-6 and tumour necrosis factor (TNF)-α concentrations, and aerobic capacity and body composition values in healthy older men.

METHODS

Eleven older men (63±8 years; 178.0±5.5 cm; 82.7±8.6 kg; 22.7±3.7% body fat) underwent SIT (6 repetitions of 30 s all-out cycling bouts with 4 min active recovery after each bout) three days a week for three consecutive weeks. Body composition measured by dual-energy X-ray absorptiometry, aerobic capacity assessed by direct peak oxygen consumption (VO<inf>2peak</inf>) test and morning fasting blood samples were obtained before and after a 3-week SIT intervention.

RESULTS

Nine supervised SIT sessions moderately (effect size [ES] =0.65; P<0.05) increased irisin concentrations (from 135.40±28.73 to 154.20±47.09 ng.mL^-1) together with moderate decreases (P<0.05) in IL-6 (ES=0.89; from 1.26±0.44 to 0.87±0.44 pg.mL^-1) and TNF-α (ES=0.64; from 5.10±1.23 to 4.31±1.20 pg.mL^-1) levels in older men. In addition, increase in VO<inf>2peak</inf> was significant but small (ES=0.25; P<0.05; from 36.0±7.1 to 37.8±6.7 mL.min.^-1kg^-1), while no changes (P>0.05) in body composition variables were observed after a short-term SIT period.

CONCLUSIONS

A 3-week SIT intervention with only nine training sessions increased circulating irisin concentrations, improved inflammatory profile and aerobic capacity without changes in body composition in healthy older men. Accordingly, a short-term SIT programme is a time efficient alternative for traditional aerobic training to improve metabolic health and aerobic capacity in older adults.

The Effect of Exercise Training on Irisin Secretion in Patients with Type 2 Diabetes: A Systematic Review

INTRODUCTION

Irisin is a myokine considered to be a potential mediator of exercise-induced energy metabolism and its secretion is known to promote the browning of beige fat cells in white adipose tissue. However, it is currently not known which exercise protocol is the best to enhance irisin concentration in patients with type 2 diabetes (T2D).

OBJECTIVE

The purpose of this study is to provide a review investigating the irisin response to different exercise training modalities and intensities in T2D.

METHODS

A systematic literature search was performed in May 2022.

RESULTS

After the selection process from 938 articles, six studies were included. Selected papers presented different exercise training interventions regarding intensity and modality. One study reported no significant differences in serum irisin levels after exercise training, whereas the other five showed a higher increase in serum irisin levels after exercise training with higher differences in irisin secretion after high-intensity training (HIT). No consideration was possible on exercise modalities.

CONCLUSIONS

The impact of training intensity and modality was found to be partly discordant but data seem to suggest that HIT promotes greater irisin secretion. Despite the limited evidence, HIT, both in interval and continuous modalities, could be suggested as valid exercise training to increase circulating irisin in patients with T2D.

Effects of exercise on irisin in subjects with overweight or obesity. A systematic review of clinical studies

Introduction

Irisin is an adipomyokine involved in white adipose tissue browning, therefore, could be a key protein in metabolic health. However, exercise effects on irisin in subjects with overweight and/or obesity are conflicting. Therefore, this systematic review aims to search and analyse the literature available on this topic. From three databases: PubMed, ScienceDirect, and Medline, clinical studies published between 2010 and 2021 were considered. From 134 found, 14 studies were included. Only six reported plasma increases after exercise (~1.2 to 3-fold from pre-exercise levels). In addition, only 1 reported significant increases in skeletal muscle irisin mRNA levels (~2-fold). Also, irisin was measured from subcutaneous adipose tissue and saliva, where a ~2-fold increase in its protein levels was found in the latter. Exercise seems to increase the circulatory concentrations of irisin in subjects with overweight or obesity. However, this response is highly variable, therefore, a more integrative approach is urgently needed.

Association Between Physical Exercise Interventions Participation and Functional Capacity in Individuals with Type 2 Diabetes: A Systematic Review and Meta-Analysis of Controlled Trials

Background

The prevalence of type 2 diabetes mellitus increases with age, and people with type 2 diabetes are more affected by reductions in functional performance. Although exercise interventions are recommended for people with diabetes, it is relevant to assess the effects of different training modes on the available functional outcomes. Therefore, our purpose was to systematically assess the effect of different physical exercise modalities in patients with type 2 diabetes with an average age of 45 years or older on outcomes used to measure functional capacity.

Methods

A systematic review and meta-analysis of controlled trials was conducted. Seven databases were searched from January 1987 to December 2021 (PubMed, Physiotherapy Evidence Database, Cochrane Library, SPORTDiscus, and in grey literature: Open Grey and Google Scholar). Eligible studies should last 8 weeks or longer, comparing structured exercise training and non-exercise control for one out of six pre-specified functional capacity outcomes (Timed Up and Go test, chair stands, walking performance, upper-limb muscle strength, lower-limb muscle strength, physical fitness parameter), in patients with type 2 diabetes, aged ≥ 45 years. The risk of bias was assessed with the Downs & Black checklist. Pooled mean differences were calculated using a random-effects model, followed by sensitivity and meta-regression analyses.

Results

Of 18,112 references retrieved, 29 trials (1557 patients) were included. Among these, 13 studies used aerobic training, 6 studies used combined training, 4 studies used resistance training, 3 studies had multiple intervention arms and 3 studies used other types of training. Exercise training was associated with an increase in functional capacity outcomes, as reflected by changes in 6-min walk test (n = 8) [51.6 m; 95% CI 7.6% to 95.6%; I² 92%], one-repetition maximum leg-press (n = 3) [18.0 kg; 95% CI 4.0% to 31.9%; I² 0%], and maximum oxygen consumption (VO_2max) (n = 20) [2.41 mL/kg·min; 95% CI 1.89% to 2.92%; I² 100%] compared with control groups. In sensitivity and subgroup analyses using VO_2max as outcome and stratified by type of study (randomized and non-randomized controlled clinical trials), duration of diabetes diagnosis, and sex, we observed overlapping confidence intervals. Meta-regression showed no association between glycated hemoglobin (HbA1C) levels and VO_2max [p = 0.34; I² 99.6%; R² = 2.6%]. In addition, the quality of the included studies was mostly low.

Conclusion

The results indicate that structured physical exercise programs might improve functional capacity in patients with type 2 diabetes, except for the upper-limb muscle strength. However, we could not identify potential effect predictors associated with directional summary estimates.

Trial registration This systematic review was registered in the PROSPERO international prospective register of systematic reviews (CRD42020162467); date of registration: 12/15/2019. The review protocol is hosted at the Open Science Framework (OSF) (Preprint https://doi.org/10.31219/osf.io/kpg2m).

Supplementary Information

The online version contains supplementary material available at 10.1186/s40798-022-00422-1.

The Potential of Exerkines in Women's COVID-19: A New Idea for a Better and More Accurate Understanding of the Mechanisms behind Physical Exercise

The benefits of physical exercise are well-known, but there are still many questions regarding COVID-19. Chow et al.'s 2022 study, titled Exerkines and Disease, showed that a special focus on exerkines can help to better understand the underlying mechanisms of physical exercise and disease. Exerkines are a group of promising molecules that may underlie the beneficial effects of physical exercise in diseases. The idea of exerkines is to understand the effects of physical exercise on diseases better. Exerkines have a high potential for the treatment of diseases and, considering that, there is still no study of the importance of exerkines on the most dangerous disease in the world in recent years, COVID-19. This raises the fundamental question of whether exerkines have the potential to manage COVID-19. Most of the studies focused on the general changes in physical exercise in patients with COVID-19, both during the illness and after discharge from the hospital, and did not investigate the basic differences. A unique look at the management of COVID-19 by exerkines, especially in obese and overweight women who experience high severity of COVID-19 and whose recovery period is long after discharge from the hospital, can help to understand the basic mechanisms. In this review, we explore the potential of exerkines in COVID-19 by practicing physical exercise to provide compelling practice recommendations with new insights.

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.

The effects of ageing, BMI and physical activity on blood IL-15 levels: A systematic review and meta-analyses

AIM

The purpose of the study was to test the effect of ageing, BMI, physical activity and chronic exercise on IL-15 blood concentration by meta-analyses of the literature.

METHODS

The search was performed on PubMed/MEDLINE, Web of Science, ProQuest, Embase and Cochrane databases. First meta-analysis compared blood IL-15 of healthy adults across three age groups (<35 years, 35-65 years, and >65 years), considering BMI as confounding factor; the second compared IL-15 levels between physically active and non-physically active individuals (cross-sectional studies); and the third tested the effect of chronic exercise interventions on blood IL-15 levels on participants of any age, sex, and health condition.

RESULTS

From 2582 studies retrieved, 67 were selected for the three meta-analyses (age effect: 59; physical activity cross-sectional effect: 5; chronic exercise effect: 14). Older adults had lower blood IL-15 than young and middle-aged adults (5.30 pg/ml [4.76; 5.83]; 7.11 pg/ml [6.33; 7.88]; 7.10 pg/ml [5.55; 8.65], respectively). However, the subgroup of overweight older adults had higher IL-15 than young and middle aged overweight adults; Habitual physical activity did not affect blood IL-15 (standardized mean difference [SMD] 0.61 [-0.65; 1.88], p = 0.34); Chronic exercise reduced blood IL-15 in short-term interventions (<16 weeks) (SMD -0.14 [-0.27; -0.01], p = 0.04), but not studies of >16 weeks of intervention (SMD 0.44 [-0.26; 1.15], p = 0.22).

CONCLUSION

The present meta-analyses highlight the complex interaction of age, BMI and physical activity on blood IL-15 and emphasize the need to take these factors into account when considering the role of this myokine in health throughout life.

The effects of exercise training induced calories expenditure on type 2 diabetes related cardio metabolic physiological parameters and adipocytokines

Background

Recently, many studies have examined the effects of various training on pro-inflammatory and anti-inflammatory adipocytes. The results of these studies are contradictory. Some have reported positive effects and others have reported negative effects. However, there is no research to study the effect of exercise on similar energy expenditures on adipocytes. Hence the purpose of this study was the effects exercise training induced calories expenditure on type 2 diabetes related cardio metabolic physiological parameters and adipocytokines.

Methods

Sixty-eight men patients with type 2 diabetes [12 weeks] were randomized to 4 groups according to training regimens. the groups are [1] HIIT [n = 17], [2] RT[n = 17], [3] AT[n = 18], and [4] AT + RT n = 16]. For 12 weeks [4 days/week, 20–30 min/season], participants performed training sessions with 300 kcal energy expenditure. Before and after 12 weeks interventions, Anthropometric and physiological variables and Glucose, insulin, FFA, LDL, HDL, TG, TC collected and analyses. Leptin, SFRP5, LGR4 and Irisin levels in Serum were assessment by ELISA.

Results

Serum irisin concentrations were significantly higher in AT [%20.4] compared to other groups. Leptin, SFRP5 and LGR4 were significantly higher in HIIT [%-21.7, %48.1 and %30.9 respectively] compared to other groups. Serum SFRP5 concentrations were significantly increased in 4 groups[P > 0.05]. However, leptin and LGR4 were significantly decreased and increased in 3 groups expect in RT group[P > 0.05]. And irisin concentrations were significantly increased in AT group only[P > 0.05]. And many variables indicated positive and negative relationship between together [P > 0.05].

Conclusions

The findings of the present study showed that if exercised with energy expenditure equal to HIIT training, it has the greatest effect on improving inflammatory and anti-inflammatory indicators in type 2 diabetic patients, as well as glycemic and lipid-chemical variables.

The effects of different types of exercise on circulating irisin levels in healthy individuals and in people with overweight, metabolic syndrome and type 2 diabetes

Irisin is a myokine secreted during exercise. It has drawn the attention of researchers as it regulates several effects of exercise that are considered beneficial. It has also been proposed as a therapeutic tool to treat metabolic disorders. In recent years, the effect of different types of training on circulating irisin has been studied in large populations. An overall beneficial result has been shown, however, the outcome of the investigations has raised some controversy. Herein we evaluated the existing literature on the effects of different types of training on the circulating irisin levels in healthy subjects and in those displaying different metabolic condition. We conducted queries in the PubMed and Web of Science databases for literature published between January 2010 and January 2021. Thirty-seven original articles were retrieved and they were included in this review. Any letter to the editor, meta-analyses, reviews, and systematic review articles were excluded. From these 37 articles, 19 of them reported increased levels of circulating irisin. The interventions encompassed aerobic, resistance, combined, circuit, and interval training types. Such increase of circulating irisin was reported for healthy subjects and for those displaying different metabolic condition. A training that is steadily kept with a moderate to high intensity, including that characterized by brief highly intense intervals, were distinguishable from the rest. Nevertheless, the training effectiveness as evaluated by the increased circulating irisin levels depends on the subject’s metabolic condition and age.

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.

Effects of aerobic exercise on fibroblast growth factor 21 in overweight and obesity. A systematic review

Fibroblast growth factor 21 (FGF21) has been suggested to improve metabolism during aerobic exercise in obesity. However, the variability of exercise interventions gives rise to discrepancies in the field. Therefore, we aimed to systematically review the available literature regarding the effects of aerobic exercise on FGF21 in the context of overweight and obesity. Our search included original articles published between 2009 and November 2021 found in PubMed, Science Direct, and Medline. Clinical and preclinical studies were included. Studies, where subjects or animals presented with other conditions (e.g., cancer, stroke), were excluded. From an initial 43 studies, 19 (clinical studies = 9; preclinical studies = 10) were eligible for inclusion in this review. The main findings were that acute exercise tended to increase circulatory levels of FGF21. In contrast, chronic exercise programs (≥4 weeks) had the opposite effect along with inducing mRNA and protein increases of FGF receptors and β-klotho in adipose tissue, liver, and skeletal muscle. In conclusion, both clinical and preclinical studies showed that aerobic exercise exerts changes in circulatory and tissue FGF21, along with its receptors and co-receptor. Future research is needed to elucidate the mechanisms, along with the physiological and clinical implications of these changes.

The Effects of Saffron (Crocus sativus L.) in conjunction with Concurrent Training on body composition, glycemic status, and inflammatory markers in obese men with type 2 diabetes mellitus: a randomized double-blind clinical trial

AIM

Chronic inflammation is one of the major challenges in the management of obesity and type 2 diabetes mellitus (T2DM). Our primary aim was to assess the anti-inflammatory effects of Saffron (Crocus sativus L.) supplementation and concurrent training in obese men with T2DM.

METHODS

Sixty obese men with T2DM (age = 39 ± 5 years; body mass = 93.9 ± 6 kg) were randomly assigned to four groups; concurrent training + placebo (CT; n = 15), saffron supplementation (S; n = 15), concurrent training + saffron supplementation (CTS; n = 15), or control (CON; n = 15). The participants in the CT group performed concurrent training (resistance + aerobic) three times per week for 12 weeks and received daily one pill of placebo (maltodextrin); the participants in the S group supplemented with one pill of 100 mg of saffron daily, and the participants in the CTS group participated in both saffron and training intervention while CON group continued regular lifestyle (no training or no supplementation). Inflammatory markers, body composition (evaluated by a multi-frequency bioelectrical impedance device; Jawon X-Contact 356), and metabolic profile were evaluated before and after interventions.

RESULTS

All three interventions significantly (p<0.05) decreased TNF-α (CT = -4.22, S = -1.91, CTS = -9.69 pg/mL), hs-CRP (CT = -0.13, S = -0.1, CTS = -0.32 ng/mL), IL-6 (CT = -6.84, S = -6.36, CTS = -13.55 pg/mL), IL-1β (CT = -8.85, S = -6.46, CTS = -19.8 pg/mL), FBG (CT = -6.97, S = -2.45, CTS = -13.86 mg/dL), insulin (CT = -0.13, S = -0.03, CTS = -0.21 mU/L), HOMA-IR (CT = -0.12, S = -0.04, CTS = -0.21), HbA1c (CT = -0.17, S = -0.11, CTS = -0.26 %), and increased IL-10 (CT = 1.09, S= 0.53, CTS = 2.27 pg/mL) concentrations. There was a positive correlation between changes in BFP with hs-CRP, IL-6, IL-1β, and TNF-α, and IL-10 concentrations across the intervention groups. Additionally, significant differences were observed between the changes for all variables in the CTS group compared to CT, S, and CON groups (p<0.05) CONCLUSION: It seems that an interactive of saffron supplementation and concurrent training has more efficient effects on the anti-inflammatory status compared to the saffron supplementation or concurrent training alone.

Close association between lifestyle and circulating FGF21 levels: A systematic review and meta-analysis

BACKGROUND

The impact of lifestyle factors on circulating fibroblast growth factor 21 (cFGF21) remains unclear. We conducted this systematic review and meta-analysis to evaluate the association between lifestyle factors and cFGF21 levels.

METHODS

We included studies that evaluated the effects of different lifestyles on cFGF21 concentration in adults, which included smoking, exercise, diets, alcohol consumption and weight loss. Random effects models or fixed effects models were used for meta-analysis to calculate the standardized mean difference (SMD) and 95% confidence interval according to the heterogeneity among studies. Study quality was assessed using the Newcastle-Ottawa Scale for cohort studies, the Joanna Briggs Institution Checklist for cross-sectional studies, and the PEDro scale for experimental studies.

RESULTS

A total of 50 studies with 1438 individuals were included. Overall, smoking, a hypercaloric carbohydrate-rich diet, a hypercaloric fat-rich diet, amino acid or protein restriction, excessive fructose intake and alcohol consumption significantly upregulated cFGF21 levels (p<0.05), whereas fish oil intake and calorie restriction with sufficient protein intake significantly decreased cFGF21 (p<0.05). Compared to the preexercise cFGF21 level, the cFGF21 level significantly increased within 3 hours postexercise (p<0.0001), while it significantly decreased in the blood sampled >6 h postexercise (p=0.01). Moreover, higher exercise intensity resulted in higher upregulation of cFGF21 at 1-hour post exercise (p=0.0006).

CONCLUSION

FGF21 could serve as a potential biomarker for the assessment of different lifestyle interventions. When it is used for this purpose, a standard study protocol needs to be established, especially taking into consideration the intervention types and the sampling time post-intervention.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021254758, identifier CRD42021254758.

Physiological Responses to Low-Volume Interval Training in Women

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

Effects of High-Intensity Interval Training on Inflammatory Biomarkers in Patients with Type 2 Diabetes. A Systematic Review

Background: Due to the prevalence and incidence worldwide of type 2 diabetes, and the significant role physical activity plays in these patients, a systematic review has been conducted to find out the effects that high-intensity interval training has on inflammatory biomarkers in subjects with type 2 diabetes. This project aims to determine the effect this training modality has on inflammatory biomarkers, in addition to observing its effects on the values of body composition and determining if this is a more effective, less effective or equally effective alternative to standard aerobic or resistance training. Methods: A search was conducted in the months of November and December 2020 on different databases: Pubmed, WoS and PEDro. A protocol for this systematic review was registered in PROSPERO (Registration number: CRD42021281186). The studies selected met the previously defined inclusion criteria, and the methodological quality of the papers used was evaluated according to the Downs and Black Checklist. Results: Out of 46 studies found, seven were included. The most relevant data concerning the characteristics of the clinical trials and HIIT characteristics, the values of body composition and the biomarkers under study were extracted from each study. Moreover, the results obtained from the different studies were described. Conclusions: HIIT could have an effect on inflammatory biomarkers. There is likely to be a relationship between changes in inflammatory profile and fat loss. A controlled diet may be a good complement to reduce the inflammatory profile. Further studies are required to determine whether HIIT is a better, worse or an equivalent alternative to medium-intensity aerobic exercise to improve the inflammatory profile.

Long-Term Effect of Exercise on Irisin Blood Levels-Systematic Review and Meta-Analysis

Physical exercise may activate a number of important biochemical processes in the human body. The aim of this systematic review and meta-analysis was to identify the long-term effect of physical activity on irisin blood levels. We searched PubMed, Scopus, and Web of Science for articles addressing the long-term effect of physical exercise on irisin blood levels. Fifty-nine articles were included in the final qualitative and quantitative syntheses. A statistically significant within-group effect of exercise on irisin blood levels was in 33 studies; out of them, the irisin level increased 23× and decreased 10×. The significant positive between-groups effect was found 11×. Furthermore, the meta-analysis indicated that physical exercise had a significant positive effect on irisin blood levels (SMD = 0.39 (95% CI 0.27–0.52)). Nevertheless, considerably high heterogeneity was found in all the analyses. This systematic review and meta-analysis indicate that physical exercise might increase irisin blood levels; however, the results of individual studies were considerably inconsistent, which questions the methodological detection of irisin by ELISA kits.

Effectiveness of combined exercise in people with type 2 diabetes and concurrent overweight/obesity: a systematic review and meta-analysis

OBJECTIVE

To synthesise the available scientific evidence on the effects of combined exercise on glycaemic control, weight loss, insulin sensitivity, blood pressure and serum lipids among patients with type 2 diabetes (T2D) and concurrent overweight/obesity.

DESIGN AND SAMPLE

PubMed, EMBASE, Web of Science, the Cochrane library, WANFANG, CNKI, SinoMed, OpenGrey and ClinicalTrials.gov were searched from inception through April 2020 to identify randomised controlled trials (RCTs) that reported the effects of combined exercise in individuals with T2D and concurrent overweight/obesity.

METHODS

Quality assessment was performed using the Cochrane Collaboration's risk of bias tool. The mean difference (MD) with its corresponding 95% CI was used to estimate the effect size. Meta-analysis was performed using Review Manager V.5.3.

RESULTS

A total of 10 RCTs with 978 participants were included in the meta-analysis. Pooled results demonstrated that combined exercise significantly reduced haemoglobin A1c (MD=-0.16%, 95% CI: -0.28 to -0.05, p=0.006); body mass index (MD=-0.98 kg/m², 95% CI: -1.41 to -0.56, p<0.001); homeostasis model assessment of insulin resistance (MD=-1.19, 95% CI: -1.93 to -0.46, p=0.001); serum insulin (MD=-2.18 μIU/mL, 95% CI: -2.99 to -1.37, p<0.001) and diastolic blood pressure (MD=-3.24 mm Hg, 95% CI: -5.32 to -1.16, p=0.002).

CONCLUSIONS

Combined exercise exerted significant effects in improving glycaemic control, influencing weight loss and enhancing insulin sensitivity among patients with T2D and concurrent overweight/obesity.

Sedentary time, physical activity, and serum SPARC in a middle-aged population

The influence of habitual physical activity (PA) on the circulating levels of secreted protein acidic and rich in cysteine (SPARC) remains unclear. The purpose of the current study was to clarify the effects of sedentary time, light-intensity PA (LPA), and moderate- to vigorous-intensity PA (MVPA) on the serum SPARC in a general middle-aged population. The current study is a cross-sectional study of 4,000 men and 6,040 women (40-69 years). Sedentary time, LPA, and MVPA were objectively measured by an accelerometer. The serum SPARC concentration was measured by enzyme-linked immunosorbent assay. Using an isotemporal substitution model, cross-sectional associations of replacing sedentary time with either LPA or MVPA on serum SPARC levels were analysed according to sex. Interactions with subject characteristics, such as the body mass index (BMI), smoking, and alcohol consumption, were also examined. In men, replacing 60 min of sedentary time with 60 min of MVPA was significantly associated with 23 ng/mL lower serum SPARC levels (confidence interval: -43, -2) after adjusting for confounders, including the BMI (P = 0.028). A significant interaction between replacing sedentary behaviour with LPA and the BMI on SPARC was detected in women (P = 0.029), although the stratified associations for each BMI level (<25 or ≥25 kg/m²) did not reach significance. The current study suggests that replacing sedentary time with MVPA is associated with reduced serum SPARC levels in middle-aged men, but not in women. In addition, a potential interaction between LPA and the BMI on SPARC was also found in women.

Effects and dose-response relationship of high-intensity interval training on cardiorespiratory fitness in overweight and obese adults: a systematic review and meta-analysis

This study aims to quantify the effects of high-intensity interval training (HIIT) on cardiorespiratory fitness (CRF) by considering potential moderators and to characterise dose-response relationships of HIIT variables that could maximise CRF improvements in overweight and obese adults. Following a comprehensive search through four electronic databases, 19 studies met eligibility criteria. Random-effects models were applied to weight all included studies and to compute the weighted mean standardised mean differences (SMD_wm). Meta-analysis showed that HIIT was a highly effective approach for improving CRF in overweight and obese adults (SMD_wm = 1.13). Effects were modified by sex and baseline CRF level. Dose-response relationship analysis provided some preliminary data regarding the training period, training intensity, and session duration. However, it is still not possible to provide accurate recommendations currently. Further studies are still needed to identify the most appropriate training variables to prescribe effective HIIT programmes for improving CRF in overweight and obese adults.

Effect of different types of regular exercise on physical fitness in adults with overweight or obesity: Systematic review and meta-analyses

This systematic review examined the effect of exercise training interventions on physical fitness in adults with overweight or obesity and compared the effectiveness of different types of exercise training. Four electronic databases were searched. Articles were included if they described randomized controlled trials of exercise training interventions and their effect on maximal oxygen consumption or muscle strength in adults with overweight or obesity. Changes in outcome parameters were analyzed using random effects meta-analyses for different training types (aerobic, resistance, combined aerobic plus resistance, and high-intensity interval training). Eighty-eight articles satisfied the inclusion criteria of which 66 (3964 participants) could be included in the meta-analyses. All training types increased VO_2max (mean difference 3.82 ml/min/kg (95% CI 3.17, 4.48), P < 0.00001; I² = 48%). In direct comparisons, resistance training was less effective in improving VO_2max than aerobic training, HIIT was slightly more effective than aerobic training, and no difference between aerobic and combined aerobic plus resistance training was found. For muscle strength benefits, incorporation of resistance exercise in the training program is indicated. Exercise training increases VO_2max and muscle strength in adults with overweight or obesity. Differences between training types should be weighed with other needs and preferences when health professionals advise on exercise training to improve physical fitness.

Effects of Exercise Intervention on Mitochondrial Stress Biomarkers in Metabolic Syndrome Patients: A Randomized Controlled Trial

Metabolic syndrome (MetS) pathogenesis involves oxidative stress associated with mitochondrial dysfunction, which triggers integrated stress responses via various compensatory metabolic modulators like mitokines and hepatokines. However, the regulatory mechanisms underlying the exercise-derived benefits with respect to mitokines and hepatokines (potential MetS biomarkers) are unknown. Thus, we investigated the effects of exercise training on MetS biomarkers and their associations with clinical parameters. In this single-center trial, 30 women with MetS were randomly assigned to 12-week supervised exercise or control groups (1:1) and compared with 12 age-matched healthy volunteers. All participants completed the study except one subject in the control group. Expectedly, serum levels of the mitokines, fibroblast growth factor-21 (FGF21), growth differentiation factor-15 (GDF15), and the hepatokine, angiopoietin-like 6 (ANGPTL6), were higher in MetS patients than in healthy volunteers. Moreover, their levels were markedly attenuated in the exercise group. Further, exercise-mediated changes in serum FGF21 and GDF15 correlated with changes in the homeostasis model of assessment of insulin resistance (HOMA-IR) and appendicular lean mass (ALM), respectively. Additionally, changes in serum triglycerides and ANGPTL6 were correlated with changes in leptin. Aberrant mitokine and hepatokine levels can be rectified by relieving metabolic stress burden. Therefore, exercise training may reduce the need for the compensatory upregulation of MetS metabolic modulators by improving gluco-lipid metabolism.

Effects of Exercise on Inflammatory Cytokines in Patients with Type 2 Diabetes: A Meta-analysis of Randomized Controlled Trials

OBJECTIVE

Inflammation is involved in the pathogenesis of type 2 diabetes (T2DM) and the occurrence of insulin resistance. The purpose of this study was to investigate the effects of exercise on inflammatory factors in patients with T2DM.

METHODS

A systematic review was conducted on five databases, Cochrane, Embase, Pubmed, Web of Science, and EBSCO. All randomized controlled trials (RCTs) published between establishment of the database and November 2020 without restrictions on language were included. Studies evaluated the effects of exercise intervention on inflammatory cytokines in patients with T2DM were selected.

RESULTS

Twenty-three randomized controlled trials (1350 patients) were included in our meta-analysis. Exercise can significantly reduce the level of C-reactive protein (CRP) (MD: -0.79, 95% CI: -1.26 to -0.33, p = 0.0008), tumor necrosis factor-α (TNF-α) (MD: -2.33, 95% CI: -3.39 to -1.27, p < 0.0001), and interleukin-6 (IL-6) (MD: -0.42, 95% CI: -0.60 to -0.24, p < 0.0001) in T2DM patients.

CONCLUSION

The findings of this review suggest that exercise reduces inflammatory cytokines (CRP, TNF-α, and IL-6) in T2DM patients. More studies with high methodological qualities and large sample sizes need to be done to confirm which forms of exercise are most effective.

Myokines: a descriptive review

In the last years, scientists have shown that skeletal muscle is not a pure locomotor unit or responsible for propulsion and posture. Skeletal muscle encompasses one of the major organs of the body (constituting about 40% of the body mass in non-obese men). It regulates energy and metabolic processes and is now recognized as an organ capable of producing molecules with vital functions. These molecules are termed myokines, a new field of research in the health sciences, and represent an open field of discoveries and applications in several areas. The aim of this review was to show the role of some well-known myokines in the maintenance of homeostasis. Our search was performed in databases such as Medline/Pubmed, Embase and Scielo. Some relevant myokines are interleukin-6 (IL-6), IL-8, IL-15, irisin, myostatin, fibroblast growth factor 21 (FGF21), leukemia inhibitory factor (LIF), brain-derived neurotrophic factor (BDNF), and insulin-like growth factor-1 (IGF-1). They are related to play a positive or negative role in muscle function and metabolism homeostasis. They are associated with the regulation of glucose and lipid metabolism, the deposition of fat in the adipose tissue, and the "browning" of the white adipose tissue. For these reasons, they can interfere with the prevention of obesity, diabetes, metabolic syndrome, and cardiovascular diseases. The discovery of the myokines has opened a new direction in understanding the effects of exercises on humans.

Resistance training attenuates circulating FGF-21 and myostatin and improves insulin resistance in elderly men with and without type 2 diabetes mellitus: A randomised controlled clinical trial

Fibroblast growth factor 21 (FGF-21) and myostatin have been proposed to be potential therapeutic target for insulin resistance in age-related metabolic disorders including type 2 diabetes (T2D). Moreover, despite the potential metabolic effect of resistance training on insulin resistance, aging, and T2D; the effect of this type of exercise training on FGF-21 and myostatin in elderly men with and without T2D are unknown. Forty-four elderly men were assigned to either the RT training (RT; without T2D: 12, with TD2 = 10) or the control group (C; without T2D: 12, with TD2 = 10). The RT group performed 12-wk resistance training intervention, 3 days/wk, 10 repetitions with 70% 1RM. At the baseline, the elderly men with T2D had a higher FGF-21 (p = 0.002) and myostatin (p = 0.02) concentrations and lower muscle strength (p = 0.01) than the elderly men without T2D. RT resulted in significant decrease in FGF-21 and myostatin concentration and increase in muscle strength in both elderly men with and without T2D (P = 0.001, for all) as well as decrease in HOMA-IR in only elderly men without T2D (P = 0.001). There was no significant difference in the RT-induced FGF-21 reduction between elderly men with and without T2D (p = 0.77, p = 0.28, respectively), but, RT caused a larger reduction in circulating myostatin in elderly men without T2D than with T2D (P = 0.007). Taken together, our results demonstrated that 12 weeks of RT induced an overall significant reduction of FGF-21 and myostatin in elderly men with and without T2D; with higher reduction of myostatin in elderly men without T2D.

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

AIM

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Circulating and tissue specific transcription of angiopoietin-like protein 4 in human Type 2 diabetes

AIMS

Obesity is associated with adipose tissue (AT) dysfunction marked by cellular hypertrophy, inflammation, hypoxia and fibrosis. Angiopoietin-like protein 4 (ANGPTL4) inhibits lipoprotein lipase which regulates triglyceride storage. Recently, inhibition of ANGPTL4 has been suggested as potential treatment for type 2 diabetes. Here we evaluate ANGPTL4's role in diabetes and examine ANGPTL4 in relation to markers of AT dysfunction and fatty liver disease.

MATERIALS & METHODS

We obtained a unique set of paired samples from subjects undergoing weight loss surgery including subcutaneous AT (SCAT), omental AT (OMAT), liver, thigh muscle biopsies and serum including a post-surgical SCAT biopsy after 9 months.

RESULTS

SCAT ANGPTL4 expression and circulating protein levels were higher in people with diabetes and correlated with glucose levels and HOMA-IR but not BMI. At post-surgical follow up, SCAT ANGPTL4 declined in subjects with diabetes to levels of those without diabetes. ANGPTL4 expression correlated with HIF1A and inflammation (MCP-1, IL-6).

CONCLUSIONS

We found that SCAT ANGPTL4 was closely linked with the expression of ANGPTL4 in the liver and represented a good proxy for liver steatosis. We suggest the elevation of ANGPTL4 levels in diabetes and the association with inflammation and hypoxia is due to a compensatory mechanism to limit further AT dysfunction. A reduction of ANGPTL4 for the treatment of T2DM as previously suggested is thus unlikely to be of further benefit.

Impact of high-intensity interval training and sprint interval training on peripheral markers of glycemic control in metabolic syndrome and type 2 diabetes

Glycemic control is essential to reduce the risk of complications associated with metabolic syndrome (MetS) and type 2 diabetes (T2D). Aerobic and resistance exercise performed alone or in combination improve glycemic control in both conditions. However, perceived lack of time and commitment are considered principal barriers to performing exercise regularly. High intensity interval training (HIIT) and sprint interval training (SIT) can be performed in a fraction of the time required for continuous aerobic exercise. A substantial scientific evidence indicates that HIIT/SIT improve glycemic control to a similar or greater extent than aerobic exercise in populations without MetS or T2D. Likewise, growing evidence suggest that HIIT/SIT improve the glycemic control during MetS and T2D. The aim of this review is to discuss the effects of interval training protocols on peripheral markers of glucose metabolism in patients with MetS and T2D.

Evaluation of Hypoglycemic Therapy Through Physical Exercise in n5STZ-Induced Diabetes Rats

BACKGROUND

Diabetes mellitus is a syndrome with multiple etiologies involving insulin, in which there is a lack of production and/or loss of sensitivity to this hormone resulting in insulin resistance. Treatment and control of this disease requires changes in diet, use of medication, and lifestyle, such as physical activity. These modifications may compromise quality-of-life if there is no proper guidance for the treatment or alert to possible complications caused by the disease.

METHODS

This study aimed to evaluate biochemical and hematological parameters, and to assess brain derived neurotrophic factor levels in diabetic Wistar rats submitted to chronic physical exercise.

RESULTS

The results demonstrated an increase in plasma concentration of brain-derived neurotrophic factor (BDNF) in association with hyperglycemia reduction in diabetic animals.

DISCUSSION

The results obtained suggest that there is a regulation of glucose homeostasis between peripheral tissues and the central nervous system. Exercise-induced BDNF also improved levels of glycemia, body weight, and dyslipidemia. In hematological evaluation, BDNF increase was positively correlated with an improvement in leukocyte parameters. Electrophoresis analyses demonstrated a reduction in levels of pro-inflammatory proteins, lipoprotein fractions, and albumin preservation in diabetic animals trained with elevated concentration of plasma BDNF.

CONCLUSION

In conclusion, this study demonstrated that chronic exercise was able to elevate BDNF levels in plasma, which resulted directly in positive hypoglycemic activity in diabetic animals and a reduction of the metabolic syndrome associated with diabetes mellitus.

Metabolic Health-The Role of Adipo-Myokines

Obesity is now a worldwide epidemic. In recent years, different phenotypes of obesity, ranging from metabolically healthy normal weight to metabolically unhealthy obese, were described. Although there is no standardized definition for these phenotypes or for metabolic health, the influence of lifestyle and early-life factors is undisputed. In this context, the ratio of muscle-to-fat tissue seems to play a crucial role. Both adipose tissue and skeletal muscle are highly heterogeneous endocrine organs secreting several hormones, with myokines and adipokines being involved in local autocrine/paracrine interactions and crosstalk with other tissues. Some of these endocrine factors are secreted by both tissues and are, therefore, termed adipo-myokines. High (cardiorespiratory) fitness as a surrogate parameter for an active lifestyle is epidemiologically linked to “better” metabolic health, even in the obese; this may be partly due to the role of adipo-myokines and the crosstalk between adipose and muscle tissue. Therefore, it is essential to consider (cardiovascular) fitness in the definition of metabolically healthy obese/metabolic health and to perform longitudinal studies in this regard. A better understanding of both the (early-life) lifestyle factors and the underlying mechanisms that mediate different phenotypes is necessary for the tailored prevention and personalized treatment of obesity.