Short-term aerobic exercise training in obese humans with type 2 diabetes mellitus improves whole-body insulin sensitivity through gains in peripheral, not hepatic insulin sensitivity

The impact of the time of day on metabolic responses to exercise in adults: A systematic and meta-analysis review

The aim of the current study is to investigate whether the time of day at which exercise is performed affects metabolic, glucose and insulin responses to exercise in adults. Databases were searched for randomised controlled (parallel and crossover) trials with participants aged from 18 to 65 year, an intervention of any exercise carried out at a specific time of the day and compared to any exercise carried out at a different time of the day. From 2458 screened articles, 12 studies were included in the systematic review of which 5 studies were included in the meta-analyses which compared 24 h continuous glucose monitoring (CGM) data, between morning and afternoon/evening exercise, on the day exercise was performed (SMD = 0.12 [-0.22-0.46] p = 0.76) and the day after exercise (SMD = -0.02 [-0.36-0.33] p = 0.94. Similar findings were observed in the wider systematic review with a general unclear risk of bias and a low certainty in these data. The results indicate that there is no clear effect of the time of the day on metabolic responses to exercise and exercise at any time of day should be the goal of public health strategies.

Effects of HIIT Interventions on Cardiorespiratory Fitness and Glycemic Parameters in Adults with Type 1 Diabetes: A Systematic Review and Meta-Analysis

BACKGROUND

Individuals with type 1 diabetes mellitus (T1DM) face impaired cardiorespiratory fitness and glycemic control, increasing the risk of cardiovascular complications. High-intensity interval training (HIIT) has emerged as a promising exercise modality with potential benefits for both aspects in this population.

OBJECTIVES

The primary aim was to investigate the effects of HIIT on cardiorespiratory fitness and glycemic parameters in patients with T1DM. The secondary aim was to examine the most effective HIIT protocol for cardiorespiratory fitness and glycemic parameters in patients with T1DM.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Two major electronic databases (Web of Science and PubMed) were searched up to February 2024.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomized and non-randomized trials involving adult patients with T1DM, free of complications and other diseases examining the effects of HIIT (HIIT pre vs. post; HIIT vs. control group or HIIT vs. moderate-intensity continuous training (MICT)) on cardiorespiratory fitness and glycemic parameters were included.

RESULTS

A total of ten studies met the inclusion criteria. The meta-analysis revealed a significant improvement in cardiorespiratory fitness following HIIT interventions (pre vs. post) in patients with T1DM (standardized mean difference (SMD) = 0.59, 95% confidence interval (CI) = 0.16 to 1, p = 0.01). Furthermore, HIIT (pre vs. post) was associated with significant improvements in 24-h mean glucose control (SMD = - 0.44, 95% CI = - 0.81 to - 0.06, p = 0.02), but the results (pre vs. post) failed to identify significant improvements in fasting glucose (SMD = - 0.26, 95% CI = - 0.78 to 0.24, p = 0.3) and glycated hemoglobin (HbA1C) values (SMD = - 0.28, 95% CI = - 0.61 to 0.05, p = 0.1). However, in comparison with a control group, HIIT showed significantly favorable effects on HbA1C (SMD = - 0.74, 95% CI = - 1.35 to - 0.14, p = 0.02). Finally, the meta-regression analysis did not find any moderating effect of any HIIT characteristics (i.e., intervention duration, session duration, work time, rest time, number of bouts, and intensity) on cardiorespiratory fitness and glycemic parameters.

CONCLUSION

Our systematic review and meta-analysis show that T1DM patients who performed a HIIT intervention significantly improved cardiorespiratory fitness and reduced their 24-h mean glucose levels, but not their HbA1C and fasting glucose. These findings support the application of HIIT interventions in T1DM patients. However, the guidelines for the most effective protocol remain unclear; hence, future studies are needed.

Gut Microbiota in the Progression of Type 2 Diabetes and the Potential Role of Exercise: A Critical Review

Type 2 diabetes (T2D) is the predominant metabolic epidemic posing a major threat to global health. Growing evidence indicates that gut microbiota (GM) may critically influence the progression from normal glucose tolerance, to pre-diabetes, to T2D. On the other hand, regular exercise contributes to the prevention and/or treatment of the disease, and evidence suggests that a possible way regular exercise favorably affects T2D is by altering GM composition toward health-promoting bacteria. However, research regarding this potential effect of exercise-induced changes of GM on T2D and the associated mechanisms through which these effects are accomplished is limited. This review presents current data regarding the association of GM composition and T2D and the possible critical GM differentiation in the progression from normal glucose, to pre-diabetes, to T2D. Additionally, potential mechanisms through which GM may affect T2D are presented. The effect of exercise on GM composition and function on T2D progression is also discussed.

Exercise induces tissue-specific adaptations to enhance cardiometabolic health

The risk associated with multiple cancers, cardiovascular disease, diabetes, and all-cause mortality is decreased in individuals who meet the current recommendations for physical activity. Therefore, regular exercise remains a cornerstone in the prevention and treatment of non-communicable diseases. An acute bout of exercise results in the coordinated interaction between multiple tissues to meet the increased energy demand of exercise. Over time, the associated metabolic stress of each individual exercise bout provides the basis for long-term adaptations across tissues, including the cardiovascular system, skeletal muscle, adipose tissue, liver, pancreas, gut, and brain. Therefore, regular exercise is associated with a plethora of benefits throughout the whole body, including improved cardiorespiratory fitness, physical function, and glycemic control. Overall, we summarize the exercise-induced adaptations that occur within multiple tissues and how they converge to ultimately improve cardiometabolic health.

Glyoxalase I is a novel target for the prevention of metabolic derangement

Obesity prevalence in the US has nearly tripled since 1975 and a parallel increase in prevalence of type 2 diabetes (T2D). Obesity promotes a myriad of metabolic derangements with insulin resistance (IR) being perhaps the most responsible for the development of T2D and other related diseases such as cardiovascular disease. The precarious nature of IR development is such that it provides a valuable target for the prevention of further disease development. However, the mechanisms driving IR are numerous and complex making the development of viable interventions difficult. The development of metabolic derangement in the context of obesity promotes accumulation of reactive metabolites such as the reactive alpha-dicarbonyl methylglyoxal (MG). MG accumulation has long been appreciated as a marker of disease progression in patients with T2D as well as the development of diabetic complications. However, recent evidence suggests that the accumulation of MG occurs with obesity prior to T2D onset and may be a primary driving factor for the development of IR and T2D. Further, emerging evidence also suggests that this accumulation of MG with obesity may be a result in a loss of MG detoxifying capacity of glyoxalase I. In this review, we will discuss the evidence that posits MG accumulation because of GLO1 attenuation is a novel target mechanism of the development of metabolic derangement. In addition, we will also explore the regulation of GLO1 and the strategies that have been investigated so far to target GLO1 regulation for the prevention and treatment of metabolic derangement.

Physical Activity and Type 2 Diabetes: In Search of a Personalized Approach to Improving β-Cell Function

Type 2 diabetes mellitus (T2DM) is one of the most widespread diseases worldwide. Lifestyle interventions, including diet and physical activity (PA), are fundamental non-pharmacological components of T2DM therapy. Exercise interventions are strongly recommended for people with or at risk of developing or already with overt diabetes, but adherence to PA guidelines in this population is still challenging. Furthermore, the heterogeneity of T2DM patients, driven by differing residual β-cell functionality, as well as the possibility of practicing different types and intensities of PA, has led to the need to develop tailored exercise and training plans. Investigations on blood glucose variation in response to exercise could help to clarify why individuals do not respond in the same way to PA, and to guide the prescription of personalized treatments. The aim of this review is to offer an updated overview of the current evidence on the effects of different regimens and modalities of PA regarding glucose sensing and β-cell secretory dynamics in individuals with prediabetes or T2DM, with a special focus on β-cell function.

Effects of a Home-Based Physical Activity Program on Blood Biomarkers and Health-Related Quality of Life Indices in Saudi Arabian Type 2 Diabetes Mellitus Patients: A Randomized Controlled Trial

The purpose of this study was to undertake a randomized control trial examining the effects of a 12-week home-based physical activity program on Saudi Arabian adults with type 2 diabetes. Sixty-four patients with type 2 diabetes mellitus were recruited from the Jazan Diabetes and Endocrinology Center, located in the Jazan region of southwestern Saudi Arabia. Patients were randomly assigned to either control, i.e., usual care (males = 46.9% and females = 53.1%, age  =  45.88 ± 8.51 years, mass  =  76.30 ± 15.16 kg, stature  =  160.59 ± 8.94 cm, body mass index (BMI)  =  29.73 ± 6.24 kg/m², years since diagnosis  =  8.12 ± 6.22 years) or a home-based physical activity (males = 50% and females = 50%, age  =  42.07 ± 9.72 years, mass  =  74.58 ± 13.67 kg, stature  =  158.94 ± 9.38 cm, BMI  =  29.44 ± 4.38 kg/m², years since diagnosis  =  12.17 ± 8.38 years) trial arms. The home-based physical activity group was required to undertake aerobic training by increasing their habitual step count by 2000 steps per day and performing resistance training 3 times per week for 12 weeks. The primary outcome was hemoglobin A1c (HbA1c), and secondary measures of anthropometrics, blood biomarkers, physical fitness, and patient-reported quality of life outcomes pertinent to type 2 diabetes were measured at timepoints, i.e., baseline, 12 weeks, and 24 weeks (follow-up). Intention-to-treat analyses revealed no significant alterations in the primary outcome (control: baseline = 8.71%, 12-weeks = 8.35%, and follow-up = 8.72%; home-based physical activity: baseline = 8.32%, 12-weeks = 8.06%, and follow-up = 8.39%) between trial arms. However, improvements in psychological wellbeing at follow-up measured using the Patient Health Questionnaire-9 were significantly greater in the home-based physical activity group (baseline = 6.84, 12-weeks = 5.96, and follow-up = 5.00) compared to the control (baseline = 6.81, 12-weeks = 5.73, and follow-up = 8.53). No other statistically significant observations were observed. Home-based physical activity is not effective in mediating improvements in HbA1c levels or secondary hematological, blood pressure, anthropometric, or fitness indices. However, given the link between psychological wellbeing and the etiology/progression of disease activity in type 2 diabetes, home-based physical activity may be effective for tertiary disease management. Future trials should examine the efficacy of relative exercise intensities greater than those in the current study.

Effect of Exercise on Liver Function and Insulin Resistance Markers in Patients with Non-Alcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Structured exercise as part of lifestyle modification plays an important role in the improvement of non-alcoholic fatty liver disease (NAFLD); however, its effectiveness has been shown to vary. This systematic review with meta-analysis investigated the effects of exercise on liver function and insulin resistance markers in patients with NAFLD.

METHODS

Six electronic databases were searched using terms related to exercise and NAFLD up to March 2022. Data were analyzed using a random-effects model to estimate the standardized mean difference (SMD) and 95% confidence interval.

RESULTS

The systematic search identified 2583 articles, of which a total of 26 studies met the inclusion criteria and were eligible. Exercise training had a moderate effect on reducing ALT (SMD: -0.59, p = 0.01) and small effects on reducing AST (SMD: -0.40, p = 0.01) and insulin (SMD: -0.43, p = 0.02). Significant reductions in ALT were found following aerobic training (SMD: -0.63, p < 0.01) and resistance training (SMD: -0.45, p < 0.001). Moreover, reductions in AST were found following resistance training (SMD: -0.54, p = 0.001), but not after aerobic training and combined training. However, reductions in insulin were found following aerobic training (SMD: -0.55, p = 0.03). Exercise interventions for <12 weeks compared to ≥12 weeks were more effective in reducing FBG and HOMA-IR, while interventions for ≥12 weeks compared to <12 weeks were more effective in reducing ALT and AST levels.

CONCLUSIONS

Our findings support the effectiveness of exercise in improving liver function markers but not in blood glucose control in NAFLD patients. Additional studies are needed to determine the exercise prescription to maximize health in these patients.

Comprehensive Approach to Medical Nutrition Therapy in Patients with Type 2 Diabetes Mellitus: From Diet to Bioactive Compounds

In the pathogenesis of type 2 diabetes mellitus (T2DM), diet plays a key role. Individualized medical nutritional therapy, as part of lifestyle optimization, is one of the cornerstones for the management of T2DM and has been shown to improve metabolic outcomes. This paper discusses major aspects of the nutritional intervention (including macro- and micronutrients, nutraceuticals, and supplements), with key practical advice. Various eating patterns, such as the Mediterranean-style, low-carbohydrate, vegetarian or plant-based diets, as well as healthy eating plans with caloric deficits have been proven to have beneficial effects for patients with T2DM. So far, the evidence does not support a specific macronutrient distribution and meal plans should be individualized. Reducing the overall carbohydrate intake and replacing high glycemic index (GI) foods with low GI foods have been shown as valid options for patients with T2DM to improve glycemic control. Additionally, evidence supports the current recommendation to reduce the intake of free sugars to less than 10% of total energy intake, since their excessive intake promotes weight gain. The quality of fats seems to be rather important and the substitution of saturated and trans fatty acids with foods rich in monounsaturated and polyunsaturated fats lowers cardiovascular risk and improves glucose metabolism. There is no benefit of supplementation with antioxidants, such as carotene, vitamins E and C, or other micronutrients, due to the lack of consistent evidence showing efficacy and long-term safety. Some studies suggest possible beneficial metabolic effects of nutraceuticals in patients with T2DM, but more evidence about their efficacy and safety is still needed.

Aquatic Exercise on Brain Activity in Type 2 Diabetic: Randomized Clinical Trial

BACKGROUND

A water-based physical exercise program is extremely important for the rehabilitation of type 2 diabetes. Little is known about its action on cerebral electrical activity.

OBJECTIVE

To evaluate the effect of a water-based physical exercise protocol on electroencephalographic activity, blood glucose levels, and functional capacity, as well as their correlation, in type 2 diabetics.

METHODS

Study design: Randomized Clinical Trial. Forty volunteers were randomized into two groups: control (n = 20) and study (n = 20). A water-based physical exercise program comprising 50 min sessions was conducted three times a week for five weeks. Assessments were performed at the pre- and post-intervention and follow-up phases. The qualitative data were compared using the Mann-Whitney test and Chi-Square. Quantitative data were compared using the Kruskal-Wallis, Independent t, and ANOVA mixed tests. The Spearman correlation coefficient was used to correlate the data.

RESULTS

The data were similar when comparing the groups. Six-minute walk test data increased in the comparison between times (p = 0.01-PrexPos). EEG data decreased in comparison between times (prexfollow-up-p < 0.05), except AF3. EEG data decreased in the timexgroup comparison (prexfollow-up and postxfollow-up-p < 0.05).

CONCLUSIONS

The water-based exercise protocol maintained electroencephalographic activity, glucose levels, and functional capacity in people with type 2 diabetes, and there was no relationship between brain electrical activity and capillary blood glucose.

The complex relationship between physical activity and diabetes: an overview

Diabetes mellitus (DM) is a widespread condition, representing a challenging disease to manage. Exercise is being increasingly recommended as part of the therapeutic regimen for DM but the management of different forms of physical activity is difficult for individuals with diabetes, trainers, and physicians. Regular exercise can improve health and well-being, helping individuals to achieve their target lipid profile, body composition, cardio-respiratory fitness, and glycemic goals. People with diabetes tend to be as inactive as the general population, with a large percentage of individuals not achieving the minimum amount of recommended physical activity levels. Indeed, several barriers to exercise exist for persons with diabetes, including sports eligibility, multi-modality management of diabetic athletes, and inadequate knowledge about adequate type and intensity of exercise. The aim of the present review is to provide the current understanding of mechanisms, recommendations, and beneficial effects of different modalities of exercise for the treatment of DM.

Influence of Maternal Exercise on Glucose and Lipid Metabolism in Offspring Stem Cells: ENHANCED by Mom

CONTEXT

Recent preclinical data suggest exercise during pregnancy can improve the metabolic phenotype not only of the mother, but of the developing offspring as well. However, investigations in human offspring are lacking.

OBJECTIVE

To characterize the effect of maternal aerobic exercise on the metabolic phenotype of the offspring's mesenchymal stem cells (MSCs).

DESIGN

Randomized controlled trial.

SETTING

Clinical research facility.

PATIENTS

Healthy female adults between 18 and 35 years of age and ≤ 16 weeks' gestation.

INTERVENTION

Mothers were randomized into 1 of 2 groups: aerobic exercise (AE, n = 10) or nonexercise control (CTRL, n = 10). The AE group completed 150 minutes of weekly moderate-intensity exercise, according to American College of Sports Medicine guidelines, during pregnancy, whereas controls attended stretching sessions.

MAIN OUTCOME MEASURES

Following delivery, MSCs were isolated from the umbilical cord of the offspring and metabolic tracer and immunoblotting experiments were completed in the undifferentiated (D0) or myogenically differentiated (D21) state.

RESULTS

AE-MSCs at D0 had an elevated fold-change over basal in insulin-stimulated glycogen synthesis and reduced nonoxidized glucose metabolite (NOGM) production (P ≤ 0.05). At D21, AE-MSCs had a significant elevation in glucose partitioning toward oxidation (oxidation/NOGM ratio) compared with CTRL (P ≤ 0.05). Immunoblot analysis revealed elevated complex I expression in the AE-MSCs at D21 (P ≤ 0.05). Basal and palmitate-stimulated lipid metabolism was similar between groups at D0 and D21.

CONCLUSIONS

These data provide evidence of a programmed metabolic phenotype in human offspring with maternal AE during pregnancy.

Effects of chronic metformin treatment on training adaptations in men and women with hyperglycemia: A prospective study

OBJECTIVE

This study aimed to determine whether chronic metformin use interferes with the improvements in insulin resistance (IR) and cardiorespiratory fitness with aerobic training in people with hyperglycemia and metabolic syndrome (MetS).

METHODS

A total of 63 middle-aged (53 [7] years) individuals with MetS and obesity (BMI = 32.8 [4.5] kg/m² ) completed 16 weeks of supervised high-intensity interval training (3 d/wk, 43 min/session). Participants were either taking metformin (EXER+MET; n = 29) or were free of any pharmacological treatment for their MetS factors (EXER; n = 34). Groups were similar in their initial cardiorespiratory fitness (maximal oxygen uptake [VO_2MAX ]), age, percentage of women, BMI, and MetS factors (z score). The effects of exercise training on IR (homeostatic model assessment of insulin resistance [HOMA-IR]), MetS z score, VO_2MAX , maximal fat oxidation during exercise, and maximal aerobic power output were measured.

RESULTS

Fasting insulin and HOMA-IR decreased similarly in both groups with training (EXER+MET: -4.3% and -10.6%; EXER: -5.3% and -14.5%; p value for time = 0.005). However, metformin use reduced VO_2MAX improvements by half (i.e., EXER+MET: 12.7%; EXER: 25.3%; p value for time × group = 0.012). Maximal fat oxidation during exercise increased similarly in both groups (EXER+MET: 20.7%; EXER: 25.3%; p value for time = 0.040). VO_2MAX gains were not associated with HOMA-IR reductions (EXER+MET: r = -0.098; p = 0.580; EXER: r = -0.255; p = 0.182).

CONCLUSIONS

Metformin use was associated with attenuated VO_2MAX improvements but did not affect fasting IR reductions with aerobic training in individuals with hyperglycemia and high cardiovascular risk (i.e., MetS).

Exercise/Physical Activity in Individuals with Type 2 Diabetes: A Consensus Statement from the American College of Sports Medicine

ABSTRACT

This consensus statement is an update of the 2010 American College of Sports Medicine position stand on exercise and type 2 diabetes. Since then, a substantial amount of research on select topics in exercise in individuals of various ages with type 2 diabetes has been published while diabetes prevalence has continued to expand worldwide. This consensus statement provides a brief summary of the current evidence and extends and updates the prior recommendations. The document has been expanded to include physical activity, a broader, more comprehensive definition of human movement than planned exercise, and reducing sedentary time. Various types of physical activity enhance health and glycemic management in people with type 2 diabetes, including flexibility and balance exercise, and the importance of each recommended type or mode are discussed. In general, the 2018 Physical Activity Guidelines for Americans apply to all individuals with type 2 diabetes, with a few exceptions and modifications. People with type 2 diabetes should engage in physical activity regularly and be encouraged to reduce sedentary time and break up sitting time with frequent activity breaks. Any activities undertaken with acute and chronic health complications related to diabetes may require accommodations to ensure safe and effective participation. Other topics addressed are exercise timing to maximize its glucose-lowering effects and barriers to and inequities in physical activity adoption and maintenance.

Skeletal Muscle Hyperemia: A Potential Bridge Between Post-exercise Hypotension and Glucose Regulation

For both healthy individuals and patients with type 2 diabetes (T2D), the hemodynamic response to regular physical activity is important for regulating blood glucose, protecting vascular function, and reducing the risk of cardiovascular disease. In addition to these benefits of regular physical activity, evidence suggests even a single bout of dynamic exercise promotes increased insulin-mediated glucose uptake and insulin sensitivity during the acute recovery period. Importantly, post-exercise hypotension (PEH), which is defined as a sustained reduction in arterial pressure following a single bout of exercise, appears to be blunted in those with T2D compared to their non-diabetic counterparts. In this short review, we describe research that suggests the sustained post-exercise vasodilation often observed in PEH may sub-serve glycemic regulation following exercise in both healthy individuals and those with T2D. Furthermore, we discuss the interplay of enhanced perfusion, both macrovascular and microvascular, and glucose flux following exercise. Finally, we propose future research directions to enhance our understanding of the relationship between post-exercise hemodynamics and glucose regulation in healthy individuals and in those with T2D.

The 10-week of aerobic-functional training improves fasting blood sugar, insulin resistance, and lipid profile in patients with diabetic peripheral neuropathy: A randomized controlled trial

Study aim: This study aimed to investigate the effect of a 10-week of combined training course on concentrations of blood sugar, Insulin Resistance (HOMA-IR), and lipid profile in patients with diabetic peripheral neuropathy.

Materials and methods: This clinical trial was performed in diabetic neuropathy women and men (30–60 years old). Participants were randomly assigned to two groups: exercise (EG; n = 10) and control (CG; n = 10). The EG performed 10-week programme with one session of aerobic exercises (40% to 70% of HRReserve) and one session of functional exercises (60–90 min/ day) at the same day for four days/week and the CG performed their daily activities. The Blood glucose, IR, and lipid profile were measured initially and after the intervention.

Results: Repeated-measures ANOVA showed significant decrease in fasting blood sugar (p < 0.01) and HOMA-IR (p < 0.01), and greater improvements in TG (p < 0.05) and LDL (p < 0.05) in EG than CG, but. HDL concentration did not show significant changes.

Conclusion: The 10-week of aerobic-functional training improves fasting blood sugar, IR, and lipid profile in patients with diabetic neuropathy.

The importance of physical activity in management of type 2 diabetes and COVID-19

Over time, various guidelines have emphasised the importance of physical activity and exercise training in the management of type 2 diabetes, chronic diseases, including cardiovascular disease and musculoskeletal disorders. The aim of this review is to evaluate the effectiveness of physical activity in people with type 2 diabetes and COVID-19. Most research to date indicates that people with type 2 diabetes who engage in both aerobic and resistance exercise see the greatest improvements in insulin sensitivity. Physical activity is now also known to be effective at reducing hospitalisation rates of respiratory viral diseases, such as COVID-19, due to the beneficial impacts of exercise on the immune system. Preliminary result indicates that home-based exercise may be an essential component in future physical activity recommendations given the current COVID-19 pandemic and the need for social distancing. This home-based physical exercise can be easily regulated and monitored using step counters and activity trackers, enabling individuals to manage health issues that benefit from physical exercise.

Enhancing oxygenation of patients with coronavirus disease 2019: Effects on immunity and other health-related conditions

Coronavirus disease 2019 (COVID-19) distresses the pulmonary system causing acute respiratory distress syndrome, which might lead to death. There is no cure for COVID-19 infection. COVID-19 is a self-limited infection, and the methods that can enhance immunity are strongly required. Enhancing oxygenation is one safe and effective intervention to enhance immunity and pulmonary functions. This review deliberates the probable influences of enhancing oxygenation on immunity and other health-connected conditions in patients with COVID-19. An extensive search was conducted through Web of Science, Scopus, Medline databases, and EBSCO for the influence of enhancing oxygenation on immunity, pulmonary functions, psycho-immune hormones, and COVID-19 risk factors. This search included clinical trials and literature and systematic reviews. This search revealed that enhancing oxygenation has a strong effect on improving immunity and pulmonary functions and psycho-immune hormones. Also, enhancing oxygenation has a self-protective role counter to COVID-19 risk factors. Lastly, this search revealed the recommended safe and effective exercise protocol to enhance oxygenation in patients with COVID-19. Enhancing oxygenation should be involved in managing patients with COVID-19 because of its significant effects on immunity, pulmonary functions, and COVID-19 risk factors. A mild to moderate cycling or walking with 60%-80% Vo2max for 20-60 min performed 2-3 times per week could be a safe and effective aerobic exercise program in patients with COVID-19 to enhance their immunity and pulmonary functions.

C-peptide enhances glucagon secretion in response to hyperinsulinemia under euglycemic and hypoglycemic conditions

Several studies have associated the presence of residual insulin secretion capability (also referred to as being C-peptide positive) with lower risk of insulin-induced hypoglycemia in patients with type 1 diabetes (T1D), although the reason is unclear. We tested the hypothesis that C-peptide infusion would enhance glucagon secretion in response to hyperinsulinemia during euglycemic and hypoglycemic conditions in dogs (5 male/4 female). After a 2-hour basal period, an intravenous (IV) infusion of insulin was started, and dextrose was infused to maintain euglycemia for 2 hours. At the same time, an IV infusion of either saline (SAL) or C-peptide (CPEP) was started. After this euglycemic period, the insulin and SAL/CPEP infusions were continued for another 2 hours, but the glucose was allowed to fall to approximately 50 mg/dL. In response to euglycemic-hyperinsulinemia, glucagon secretion decreased in SAL but remained unchanged from the basal period in CPEP condition. During hypoglycemia, glucagon secretion in CPEP was 2 times higher than SAL, and this increased net hepatic glucose output and reduced the amount of exogenous glucose required to maintain glycemia. These data suggest that the presence of C-peptide during IV insulin infusion can preserve glucagon secretion during euglycemia and enhance it during hypoglycemia, which could explain why T1D patients with residual insulin secretion are less susceptible to hypoglycemia.

TRPV1 (Transient Receptor Potential Vanilloid 1) Sensitization of Skeletal Muscle Afferents in Type 2 Diabetic Rats With Hyperglycemia

[Figure: see text].

The Influence of Physical Activity on the Bioactive Lipids Metabolism in Obesity-Induced Muscle Insulin Resistance

High-fat diet consumption and lack of physical activity are important risk factors for metabolic disorders such as insulin resistance and cardiovascular diseases. Insulin resistance is a state of a weakened response of tissues such as skeletal muscle, adipose tissue, and liver to insulin, which causes an increase in blood glucose levels. This condition is the result of inhibition of the intracellular insulin signaling pathway. Skeletal muscle is an important insulin-sensitive tissue that accounts for about 80% of insulin-dependent glucose uptake. Although the exact mechanism by which insulin resistance is induced has not been thoroughly understood, it is known that insulin resistance is most commonly associated with obesity. Therefore, it is believed that lipids may play an important role in inducing insulin resistance. Among lipids, researchers’ attention is mainly focused on biologically active lipids: diacylglycerols (DAG) and ceramides. These lipids are able to regulate the activity of intracellular enzymes, including those involved in insulin signaling. Available data indicate that physical activity affects lipid metabolism and has a positive effect on insulin sensitivity in skeletal muscles. In this review, we have presented the current state of knowledge about the impact of physical activity on insulin resistance and metabolism of biologically active lipids.

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

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

Exercise-Induced Improvements to Whole Body Glucose Metabolism in Type 2 Diabetes: The Essential Role of the Liver

Type 2 diabetes (T2D) is a metabolic disease characterized by obesity, insulin resistance, and the dysfunction of several key glucoregulatory organs. Among these organs, impaired liver function is recognized as one of the earliest contributors to impaired whole-body glucose homeostasis, with well-characterized hepatic insulin resistance resulting in elevated rates of hepatic glucose production (HGP) and fasting hyperglycemia. One portion of this review will provide an overview of how HGP is regulated during the fasted state in healthy humans and how this process becomes dysregulated in patients with T2D. Less well-appreciated is the liver's role in post-prandial glucose metabolism, where it takes up and metabolizes one-third of orally ingested glucose. An abundance of literature has shown that the process of hepatic glucose uptake is impaired in patients with T2D, thereby contributing to glucose intolerance. A second portion of this review will outline how hepatic glucose uptake is regulated during the post-prandial state, and how it becomes dysfunctional in patients with T2D. Finally, it is well-known that exercise training has an insulin-sensitizing effect on the liver, which contributes to improved whole-body glucose metabolism in patients with T2D, thereby making it a cornerstone in the management of the disease. To this end, the impact of exercise on hepatic glucose metabolism will be thoroughly discussed, referencing key findings in the literature. At the same time, sources of heterogeneity that contribute to inconsistent findings in the field will be pointed out, as will important topics for future investigation.

Impact of short- and long-term electrically induced muscle exercise on gene signaling pathways, gene expression, and PGC1a methylation in men with spinal cord injury

Exercise attenuates the development of chronic noncommunicable diseases (NCDs). Gene signaling pathway analysis offers an opportunity to discover if electrically induced muscle exercise regulates key pathways among people living with spinal cord injury (SCI). We examined short-term and long-term durations of electrically induced skeletal muscle exercise on complex gene signaling pathways, specific gene regulation, and epigenetic tagging of PGC1a, a major transcription factor in skeletal muscle of men with SCI. After short- or long-term electrically induced exercise training, participants underwent biopsies of the trained and untrained muscles. RNA was hybridized to an exon microarray and analyzed by a gene set enrichment analysis. We discovered that long-term exercise training regulated the Reactome gene sets for metabolism (38 gene sets), cell cycle (36 gene sets), disease (27 gene sets), gene expression and transcription (22 gene sets), organelle biogenesis (4 gene sets), cellular response to stimuli (8 gene sets), immune system (8 gene sets), vesicle-mediated transport (4 gene sets), and transport of small molecules (3 gene sets). Specific gene expression included: oxidative catabolism of glucose including PDHB (P < 0.001), PDHX (P < 0.001), MPC1 (P < 0.009), and MPC2 (P < 0.007); Oxidative phosphorylation genes including SDHA (P < 0.006), SDHB (P < 0.001), NDUFB1 (P < 0.002), NDUFA2 (P < 0.001); transcription genes including PGC1α (P < 0.030) and PRKAB2 (P < 0.011); hypertrophy gene MSTN (P < 0.001); and the myokine generating FNDC5 gene (P < 0.008). Long-term electrically induced exercise demethylated the major transcription factor PGC1a. Taken together, these findings support that long-term electrically induced muscle activity regulates key pathways associated with muscle health and systemic metabolism.

A novel fast-slow model of diabetes progression: Insights into mechanisms of response to the interventions in the Diabetes Prevention Program

Several models for the long-term development of T2DM already exist, focusing on the dynamics of the interaction between glycemia, insulinemia and β-cell mass. Current models consider representative (fasting or daily average) glycemia and insulinemia as characterizing the compensation state of the subject at some instant in slow time. This implies that only these representative levels can be followed through time and that the role of fast glycemic oscillations is neglected. An improved model (DPM15) for the long-term progression of T2DM is proposed, introducing separate peripheral and hepatic (liver and kidney) insulin actions. The DPM15 model no longer uses near-equilibrium approximation to separate fast and slow time scales, but rather describes, at each step in slow time, a complete day in the life of the virtual subject in fast time. The model can thus represent both fasting and postprandial glycemic levels and describe the effect of interventions acting on insulin-enhanced tissue glucose disposal or on insulin-inhibited hepatic glucose output, as well as on insulin secretion and β-cell replicating ability. The model can simulate long-term variations of commonly used clinical indices (HOMA-B, HOMA-IR, insulinogenic index) as well as of Oral Glucose Tolerance or Euglycemic Hyperinsulinemic Clamp test results. The model has been calibrated against observational data from the Diabetes Prevention Program study: it shows good adaptation to observations as a function of very plausible values of the parameters describing the effect of such interventions as Placebo, Intensive LifeStyle and Metformin administration.

Aerobic exercise training improves hepatic and muscle insulin sensitivity, but reduces splanchnic glucose uptake in obese humans with type 2 diabetes

BACKGROUND

Aerobic exercise training is known to have beneficial effects on whole-body glucose metabolism in people with type 2 diabetes (T2D). The responses of the liver to such training are less well understood. The purpose of this study was to determine the effect of aerobic exercise training on splanchnic glucose uptake (SGU) and insulin-mediated suppression of endogenous glucose production (EGP) in obese subjects with T2D.

METHODS

Participants included 11 obese humans with T2D, who underwent 15 ± 2 weeks of aerobic exercise training (AEX; n = 6) or remained sedentary for 15 ± 1 weeks (SED; n = 5). After an initial screening visit, each subject underwent an oral glucose load clamp and an isoglycemic/two-step (20 and 40 mU/m²/min) hyperinsulinemic clamp (ISO-clamp) to assess SGU and insulin-mediated suppression of EGP, respectively. After the intervention period, both tests were repeated.

RESULTS

In AEX, the ability of insulin to suppress EGP was improved during both the low (69 ± 9 and 80 ± 6% suppression; pre-post, respectively; p < 0.05) and high (67 ± 6 and 82 ± 4% suppression, respectively; p < 0.05) insulin infusion periods. Despite markedly improved muscle insulin sensitivity, SGU was reduced in AEX after training (22.9 ± 3.3 and 9.1 ± 6.0 g pre-post in AEX, respectively; p < 0.05).

CONCLUSIONS

In obese T2D subjects, exercise training improves whole-body glucose metabolism, in part, by improving insulin-mediated suppression of EGP and enhancing muscle glucose uptake, which occur despite reduced SGU during an oral glucose challenge.

Clinical characteristics of patients under 40 years old with early-onset hyperuricaemia: a retrospective monocentric study in China

OBJECTIVE

To investigate the clinical characteristics of patients with early-onset hyperuricaemia (HUC).

METHODS

A retrospective study using data from the Second Affiliated Hospital of Soochow University was conducted. 623 patients with HUC were divided into early-onset group and late-onset group. Another 201 healthy subjects ≤40 years old were regarded as control group. The data of physical measurements and biochemistry test were collected. Clinical data of early-onset group were compared with late-onset group and control group by analysis of variance (ANOVA) and χ² test. Principal component analysis (PCA) was applied. Logistic regression was used to identify the clinical factors correlated with patients with early-onset HUC.

RESULTS

The patients of early-onset group had different body mass index (BMI), serum albumin, alanine transaminase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AKP), gamma-glutamyltransferase (GGT), creatinine (Cr), triglyceride (TG), total cholesterol (TC), low density lipoprotein (LDL), TG/high density lipoprotein (HDL) ratio, HDL and percentage of males, hypertension (HBP) as well as fatty liver compared with healthy people in the control group. Early-onset group patients had different albumin, ALT, fasting blood glucose, Cr, percentage of males and HBP compared with late-onset group patients. PCA identified four significant patterns including PC1 (labelled 'TG and HDL'), PC2 (labelled 'fatty liver and liver enzymes'), PC3 (labelled 'TC and LDL') and PC4 (labelled 'AKP'). The results of univariate and multivariate logistic regression analysis showed that BMI, HBP and albumin were correlative factors for early onset of HUC when the patients with early-onset and late-onset HUC were involved, while gender, BMI, PC1, PC2 and PC4 were correlative factors for early-onset HUC when the early-onset and control groups were involved.

CONCLUSION

This study described a group of patients with early-onset HUC with distinct clinical features. Gender, BMI, 'TG and HDL', 'fatty liver and liver enzymes' and 'AKP' have higher values than HBP, type 2 diabetes mellitus and 'TC and LDL' in patients under 40 years old with early-onset HUC.

New-Onset Post-Transplant Diabetes Mellitus after Allogeneic Hematopoietic Cell Transplant Is Initiated by Insulin Resistance, Not Immunosuppressive Medications

New-onset post-transplant diabetes mellitus (PTDM) occurs frequently after allogeneic hematopoietic cell transplant (HCT). Although calcineurin inhibitors and corticosteroids are assumed to be the cause for hyperglycemia, patients developing PTDM have elevated fasting C-peptide levels before HCT and before immunosuppressive medications. To determine if PTDM results from established insulin resistance present before transplant, we performed oral glucose tolerance tests (OGTTs) and measured whole body, peripheral, and hepatic insulin sensitivity with euglycemic hyperinsulinemic clamps before and 90 days after HLA-identical sibling donor HCT in 20 patients without pretransplant diabetes. HCT recipients were prospectively followed for the development of new-onset PTDM defined as a weekly fasting blood glucose ≥ 126 mg/dL or random blood glucose ≥ 200 mg/dL. During the first 100 days all patients received calcineurin inhibitors, and 11 individuals (55%) were prospectively diagnosed with new-onset PTDM. PTDM diagnosis preceded corticosteroid treatment. During the pretransplant OGTT, elevated fasting (87 mg/dL versus 101 mg/dL; P = .005) but not 2-hour postprandial glucose levels predicted PTDM diagnosis (P = .648). In response to insulin infusion during the euglycemic hyperinsulinemic clamp, patients developing PTDM had lower whole body glucose utilization (P = .047) and decreased peripheral/skeletal muscle uptake (P = .031) before and after transplant, respectively, when compared with non-PTDM patients. Hepatic insulin sensitivity did not differ. Survival was decreased in PTDM patients (2-year estimate, 55% versus 100%; P = .039). Insulin resistance before HCT is a risk factor for PTDM independent of immunosuppression. Fasting pretransplant glucose levels identified PTDM susceptibility, and peripheral insulin resistance could be targeted for prevention and treatment of PTDM after HCT.

Moderate-intensity continuous training: is it as good as high-intensity interval training for glycemic control in type 2 diabetes?

In Egypt, type 2 diabetes is higher in females than in males. Moderate-intensity continuous training (MICT) has been the most widely used exercise form in type 2 diabetes. This study aims to compare the classical MICT to the newly popular high intensity interval training (HIIT) with regard to changes in glycosylated hemoglobin (HbA1c) and estimated average glucose (eAG) in female type 2 diabetics. Twenty-six female patients with type 2 diabetes were assigned into three groups: a control group (n=9), a MICT group (n=9), and a HIIT group (n=8). Patients in both groups exercised on treadmill three days/week for 8 weeks. Patients in MICT exercised continuously for about 40 min at 65%–75% of peak heart rate (HRpeak). Patients in HIIT exercised for 4×4 min at 85%–90% of HRpeak with 3-min recovery in between at 65%–75% of HRpeak. Results showed that HbA1c was reduced significantly from 8.2% (7.45%–8.65%) to 6.9% (6.6%–7.15%) in MICT and from 8.23% (7.94%–8.85%) to 6.25% (6.1%–6.89%) in HIIT after interventions. Likewise, eAG was significantly reduced from 188.64 mg/dL (167.11–201.55 mg/dL) to 151.33 mg/dL (142.72–158.50 mg/dL) in MICT and from 189.64 mg/dL (181.18–207.29 mg/dL) to 136.69 mg/dL (128.37–151.04 mg/dL) in HIIT. No significant difference was found between HIIT and MICT in the measured variables. It is concluded that the less physically demanding MICT is as good as HIIT for normalizing hyperglycemia in type 2 diabetic females. Therefore, recent interests surrounding HIIT should not overemphasize it compared to the traditional MICT for improving glycemic outcomes.

Preliminary efficacy and feasibility of referral to exercise specialists, psychologists and provision of a technology-based behavior change support package to promote physical activity in school teachers 'at risk' of, or diagnosed with, type 2 diabetes: The 'SMART Health' Pilot Study Protocol

INTRODUCTION

Type 2 diabetes mellitus (T2DM) is a global public health concern. Aerobic physical activity (PA) and resistance training (RT) play significant roles in the prevention and management of T2DM. The aim of this pilot trial is to determine the preliminary efficacy and confirm feasibility of referral to exercise physiologists, psychologists, and provision of a technology-based behavior change support package to promote aerobic PA and RT in school teachers 'at risk' of or diagnosed with T2DM.

RESEARCH DESIGN AND METHODS

The SMART (Support, Motivation and Physical Activity Research for Teachers') Health pilot study will be evaluated using a three-arm randomized controlled trial. The intervention will be guided by Social Cognitive Theory, Health Action Process Approach Model and Cognitive Behavioral Therapy strategies. The participants will be randomly allocated to one of three study groups: Group 1: wait-list control group; Group 2: 5 face-to-face visits with a psychologist and exercise specialist over 3 months; and Group 3: same as Group 2 plus technology-based behavior change support package for an additional 6 months. Assessments will be conducted at baseline, 3-, 9- (primary time-point) and 18-months post-baseline. The primary outcome will be PA measured with pedometers.

DISCUSSION

SMART Health is an innovative, multi-component intervention, that integrates referral to exercise specialists, psychologists and provision of a technology-based behavior support package to promote PA and RT in adults diagnosed with T2DM or 'at risk' of T2DM. The findings will be used to guide future PA interventions and to develop effective community-based diabetes prevention and treatment programs.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry No: ACTRN12616001309471.

Proarrhythmic Remodeling of Calcium Homeostasis in Cardiac Disease; Implications for Diabetes and Obesity

A rapid growth in the incidence of diabetes and obesity has transpired to a major heath issue and economic burden in the postindustrial world, with more than 29 million patients affected in the United States alone. Cardiovascular defects have been established as the leading cause of mortality and morbidity of diabetic patients. Over the last decade, significant progress has been made in delineating mechanisms responsible for the diminished cardiac contractile function and enhanced propensity for malignant cardiac arrhythmias characteristic of diabetic disease. Rhythmic cardiac contractility relies upon the precise interplay between several cellular Ca²⁺ transport protein complexes including plasmalemmal L-type Ca²⁺ channels (LTCC), Na⁺-Ca²⁺ exchanger (NCX1), Sarco/endoplasmic Reticulum (SR) Ca²⁺-ATPase (SERCa2a) and ryanodine receptors (RyR2s), the SR Ca²⁺ release channels. Here we provide an overview of changes in Ca²⁺ homeostasis in diabetic ventricular myocytes and discuss the therapeutic potential of targeting Ca²⁺ handling proteins in the prevention of diabetes-associated cardiomyopathy and arrhythmogenesis.

Proarrhythmic Remodeling of Calcium Homeostasis in Cardiac Disease; Implications for Diabetes and Obesity

A rapid growth in the incidence of diabetes and obesity has transpired to a major heath issue and economic burden in the postindustrial world, with more than 29 million patients affected in the United States alone. Cardiovascular defects have been established as the leading cause of mortality and morbidity of diabetic patients. Over the last decade, significant progress has been made in delineating mechanisms responsible for the diminished cardiac contractile function and enhanced propensity for malignant cardiac arrhythmias characteristic of diabetic disease. Rhythmic cardiac contractility relies upon the precise interplay between several cellular Ca²⁺ transport protein complexes including plasmalemmal L-type Ca²⁺ channels (LTCC), Na⁺-Ca²⁺ exchanger (NCX1), Sarco/endoplasmic Reticulum (SR) Ca²⁺-ATPase (SERCa2a) and ryanodine receptors (RyR2s), the SR Ca²⁺ release channels. Here we provide an overview of changes in Ca²⁺ homeostasis in diabetic ventricular myocytes and discuss the therapeutic potential of targeting Ca²⁺ handling proteins in the prevention of diabetes-associated cardiomyopathy and arrhythmogenesis.

Proarrhythmic Remodeling of Calcium Homeostasis in Cardiac Disease; Implications for Diabetes and Obesity

A rapid growth in the incidence of diabetes and obesity has transpired to a major heath issue and economic burden in the postindustrial world, with more than 29 million patients affected in the United States alone. Cardiovascular defects have been established as the leading cause of mortality and morbidity of diabetic patients. Over the last decade, significant progress has been made in delineating mechanisms responsible for the diminished cardiac contractile function and enhanced propensity for malignant cardiac arrhythmias characteristic of diabetic disease. Rhythmic cardiac contractility relies upon the precise interplay between several cellular Ca²⁺ transport protein complexes including plasmalemmal L-type Ca²⁺ channels (LTCC), Na⁺-Ca²⁺ exchanger (NCX1), Sarco/endoplasmic Reticulum (SR) Ca²⁺-ATPase (SERCa2a) and ryanodine receptors (RyR2s), the SR Ca²⁺ release channels. Here we provide an overview of changes in Ca²⁺ homeostasis in diabetic ventricular myocytes and discuss the therapeutic potential of targeting Ca²⁺ handling proteins in the prevention of diabetes-associated cardiomyopathy and arrhythmogenesis.

Effect of exercise modality on markers of insulin sensitivity and blood glucose control in pregnancies complicated with gestational diabetes mellitus: a systematic review

BACKGROUND/AIM

Exercise can be used as a strategy to attenuate hyperglycaemia experienced during gestational diabetes mellitus (GDM). To maximize its use for clinical management, the most effective modality should be identified. The purpose of this review is to elucidate the most effective modality of exercise on insulin sensitivity and blood glucose control in pregnant women with or at risk of GDM.

METHODS

A search was undertaken in MEDLINE, PubMed, Scopus, CINAHL, the Cochrane Library, Embase and the Maternity & Infant Healthcare Database. Studies that met inclusion criteria were randomized controlled trials and case-controlled studies, which compared exercise interventions with standard care during pregnancy in women with or at risk of GDM.

RESULTS

Two interventions using resistance training, eight using aerobic exercise and two using a combination of both modalities were included. The interventions showed consistently that requirements of insulin therapy, dosage, and latency to administration were improved in the exercise groups. Less consistent results were observed for capillary blood glucose measurements; however, both modalities and combination of modalities were effective at improving blood glucose control in already diagnosed patients and pregnant women with obesity. Discrepancies in the timing of intervention, GDM diagnostic criteria, and the different measures used to assess glucose metabolism make it difficult to draw clear recommendations.

CONCLUSION

Exercising three times per week for 40-60 min at 65-75% age-predicted heart rate maximum using cycling, walking or circuit training as a modality improved glycaemic control in GDM patients and reduced incidence of GDM in pregnant women with obesity. Further studies looking specifically at the effects of different modalities of exercise on glucose metabolism with combined strategies to enhance insulin sensitivity should be explored to maximize benefits for GDM pregnancies. Consistency in design and delivery of exercise-only interventions is required to make recommendations on a suitable exercise prescription in this population. In practice, adherence to consensus in diagnostic cut-offs for GDM diagnosis is fundamental for standardizing future research.

Glucose Tolerance is Linked to Postprandial Fuel Use Independent of Exercise Dose

PURPOSE

The optimal short-term exercise dose to improve glucose tolerance in relation to metabolic flexibility and/or insulin resistance is unknown. Therefore, we tested if short-term, work-matched continuous (CONT) versus interval (INT) exercise training improves glucose tolerance in part by reducing insulin resistance and increasing metabolic flexibility independent of clinically meaningful fat loss in adults with prediabetes.

METHODS

Subjects (age = 60.9 ± 1.4 yr, body mass index = 33.5 ± 1.1 kg·m) were screened for prediabetes using the American Diabetes Association criteria (75 g oral glucose tolerance test [OGTT] and/or HbA1c) and were randomized to 60 min·d of supervised CONT (n = 17, 70% HRpeak) or work-matched INT (n = 14; 90% HRpeak for 3 min and 50% HRpeak for 3 min) exercise for 12 bouts. Fitness (V˙O2peak) and body composition were assessed pre- and postintervention. A 180-min 75-g OGTT was performed, and glucose, insulin, and free fatty acids were collected to calculate glucose tolerance (tAUC180min) and whole-body as well as adipose tissue insulin resistance pre- and postintervention. RER (indirect calorimetry) was also measured at 0, 60, 120, and 180 min of the OGTT to assess fasting and postprandial metabolic flexibility.

RESULTS

CONT and INT training improved V˙O2peak (L·min; P = 0.001) and glucose tolerance (P = 0.01) and reduced fasting RER (P = 0.006), as well as whole-body and adipose insulin resistance (both P = 0.02) with no effect on body fat (P = 0.18). Increased postprandial RER was correlated with reduced glucose tAUC180min (r = -0.38, P = 0.05) and increased 180-min RER related to decreased whole-body insulin resistance (r = -0.42, P = 0.03).

CONCLUSION

Independent of exercise dose and fat loss, short-term training improves glucose tolerance in relation to enhanced postprandial fuel use.

Pre-exercise blood glucose affects glycemic variation of aerobic exercise in patients with type 2 diabetes treated with continuous subcutaneous insulin infusion

AIMS

Considering the insulin sensitivity may increase by exercise particularly in patients with type 2 diabetes (T2D), glycemic variation during exercise needs to be studied when the patients are treated with insulin. This study aimed to explore the influence factors of the efficacy and safety of aerobic exercise in patients with T2D treated with Continuous Subcutaneous Insulin Infusion (CSII).

METHODS

A total of 267 patients with T2D, treated with CSII, were included. Glycemic variations were assessed by continuous glucose monitoring (CGM). Patients were asked to complete 30 min aerobic exercise for at least one time during CGM. The patients were divided into effective and ineffective group by incremental glucose area under curve from 0 to 60 min after exercise (AUC_{0-60 min}).

RESULTS

The patients completed a total of 776 times of aerobic exercises. Blood glucose decreased fastest in the first 60 min of exercise. Pre-exercise blood glucose (PEBG) was negatively correlated with AUC_{0-60 min} (standardized β = -0.386, P < 0.001) and incremental AUC of blood glucose ≤ 4.4 mmol/L (standardized β = -0.078, P = 0.034), and was significantly higher in effective group than in ineffective group (P < 0.001). The Δglucose AUC_{0-60 min} during post-dinner was significantly higher than that during pre-lunch, post-lunch and pre-dinner (P < 0.05 for all).

CONCLUSIONS

PEBG is positively correlated with efficacy of aerobic exercise. Aerobic exercise will not worsen hyperglycemia when the PEBG > 16.7 mmol/L. Post-dinner exercise decreases the blood glucose better than other periods of the day.

CLINICAL TRIALS REGISTRATION

ChiCTR-ONC-17010400, www.chictr.org.cn.

Measurement of postprandial glucose fluxes in response to acute and chronic endurance exercise in healthy humans

The effect of endurance exercise on enhancing insulin sensitivity and glucose flux has been well established with techniques such as the hyperinsulinemic clamp. Although informative, such techniques do not emulate the physiological postprandial state, and it remains unclear how exercise improves postprandial glycaemia. Accordingly, combining mixed-meal tolerance testing and the triple-stable isotope glucose tracer approach, glucose fluxes [rates of meal glucose appearance (Ra), disposal (Rd), and endogenous glucose production (EGP)] were determined following acute endurance exercise (1 h cycling; ~70% V̇o_2max) and 4 wk of endurance training (cycling 5 days/wk). Training was associated with a modest increase in V̇o_2max (~7%, P < 0.001). Postprandial glucose and insulin responses were reduced to the same extent following acute and chronic training. Interestingly, this was not accompanied by changes to rates of meal Ra, Rd, or degree of EGP suppression. Glucose clearance (Rd relative to prevailing glucose) was, however, enhanced with acute and chronic exercise. Furthermore, the duration of EGP suppression was shorter with acute and chronic exercise, with EGP returning toward fasting levels more rapidly than pretraining conditions. These findings suggest that endurance exercise influences the efficiency of the glucoregulatory system, where pretraining rates of glucose disposal and production were achieved at lower glucose and insulin levels. Notably, there was no influence of chronic training over and above that of a single exercise bout, providing further evidence that glucoregulatory benefits of endurance exercise are largely attributed to the residual effects of the last exercise bout.

Effect of 7 days of exercise on exogenous carbohydrate oxidation and insulin resistance in children with obesity

The capacity to match carbohydrate (CHO) oxidation with CHO availability (deemed metabolic flexibility (MetFlex)) may be important for type 2 diabetes prevention. In adults, impaired MetFlex is associated with insulin resistance (IR), which can be improved with as little as 7 days of exercise. Whether this occurs similarly in children is unknown. We hypothesized that 7 consecutive days of exercise would improve MetFlex and IR in children with obesity. Twelve children (8 boys, 4 girls) completed 2 study visits before (PRE) and 2 study visits after (POST) exercise training. At visit 1, fasting blood was collected, and anthropometry and maximal oxygen uptake were assessed. At visit 2, a ¹³C-enriched CHO drink was ingested before exercise (3 × 20 min) at ∼59% maximal oxygen uptake. Exogenous CHO oxidative efficiency, used as a surrogate measurement of MetFlex, was calculated from breath samples. During training, participants alternated between continuous and high-intensity interval cycling sessions at home under supervision. In spite of good training adherence, there was no improvement in MetFlex (PRE: 20.7% ± 1.8%, POST: 18.9% ± 4.9%, p = 0.22) or homeostasis model assessment of insulin resistance (PRE: 8.7 ± 4.6, POST: 8.1 ± 6.0, p = 0.51). Future research should investigate exercise volume, sex, and pubertal effects on the early responsiveness of MetFlex to exercise therapy.

The impact of structured physical activity on glycaemic control in diabetes prevention programmes: A systematic review

Background:

Seven landmark randomised controlled trials, with some that began as early as the 1990s, observed the prediabetic state, namely, impaired glucose tolerance and impaired fasting glucose conditions, against the impact of lifestyle interventions such as physical activity, to prevent or delay the onset of type 2 diabetes mellitus. In addition to the landmark trials, this systematic review examines 14 studies that retained a focus on prediabetic individuals and measured the efficacy of physical activity on improving glucose tolerance.

Results:

Type, duration and intensity of structured physical activity can have unique benefits to prediabetic individuals. It is posited that diabetes prevention programmes must target prediabetic individuals as belonging to a high-risk group, separate and distinct from those identified with overall risk factors. While the transition from prediabetes to type 2 diabetes mellitus is not completely deterministic, the conversion rate is phenomenally higher among those with impaired glucose tolerance than those with normal glucose levels.

Conclusion:

Tenets of health behaviour models do support inferences that prediabetic individuals are potentially more inclined to weighing the risks and benefits of progressive illnesses and would therefore be more receptive to active participation in interventions. More research is required to develop evidence-based diabetes prevention programmes linked to structured physical activity intervention.

Acute exercise does not impair renal function in nondialysis chronic kidney disease patients regardless of disease stage

Exercise has been overlooked as a potential therapy in chronic kidney disease (CKD), mainly because of a lack of understanding on its safety aspects. Notably, there are no data on renal function after exercise in CKD considering its stages. We investigated the acute effects of a 30-min moderate-intensity aerobic exercise bout on glomerular filtration rate (GFR) and albuminuria in 22 nondialysis CKD patients divided into: CKD stages 1 and 2 (CKD_1-2) and CKD stages 3 and 4 (CKD_3-4). Eleven body mass index-, age-, and sex-matched healthy individuals served as control (CON). Blood and urine samples were collected before, immediately after, and up to 90 min postexercise for creatinine and albumin assessments. GFR was determined by creatinine clearance (GFR_Cr-Cl). All CKD patients had significantly lower peak oxygen uptake than CON. CKD_1-2 and CKD_3-4 had increasingly higher serum creatinine than CON (9.6 ± 2.6, 25.6 ± 1.01, and 7.5 ± 1.4 mg/l, respectively); however, no within-group changes in serum or urinary creatinine were observed across time. GFR_Cr-Cl was decreased in CKD_1-2 and CKD_3-4 compared with CON (91 ± 17 ml·min^-1·1.73 m^-2; 34 ± 15 ml·min^-1·1.73 m^-2; 122 ± 20 ml·min^-1·1.73 m^-2, respectively). Most importantly, exercise did not affect GFR_Cr-Cl in none of the groups across time. Albuminuria was significantly higher in CKD_3-4 (297 ± 284 µg/min) than in CON (5.4 ± 1.4 µg/min), but no within-group changes were observed after exercise. In conclusion, a single 30-min moderate-intensity aerobic exercise bout does not impair renal function in nondialysis CKD patients, regardless of disease stage, supporting the notion that exercise training can be safe in this disease.

The essential role of exercise in the management of type 2 diabetes

Exercise is typically one of the first management strategies advised for patients newly diagnosed with type 2 diabetes. Together with diet and behavior modification, exercise is an essential component of all diabetes and obesity prevention and lifestyle intervention programs. Exercise training, whether aerobic or resistance training or a combination, facilitates improved glucose regulation. High-intensity interval training is also effective and has the added benefit of being very time-efficient. While the efficacy, scalability, and affordability of exercise for the prevention and management of type 2 diabetes are well established, sustainability of exercise recommendations for patients remains elusive.

Exercise improves glycaemic control in women diagnosed with gestational diabetes mellitus: a systematic review

QUESTION

Does exercise improve postprandial glycaemic control in women diagnosed with gestational diabetes mellitus?

DESIGN

A systematic review of randomised trials.

PARTICIPANTS

Pregnant women diagnosed with gestational diabetes mellitus.

INTERVENTION

Exercise, performed more than once a week, sufficient to achieve an aerobic effect or changes in muscle metabolism.

OUTCOME MEASURES

Postprandial blood glucose, fasting blood glucose, glycated haemoglobin, requirement for insulin, adverse events and adherence.

RESULTS

This systematic review identified eight randomised, controlled trials involving 588 participants; seven trials (544 participants) had data that were suitable for meta-analysis. Five trials scored ≥ 6 on the PEDro scale, indicating a relatively low risk of bias. Meta-analysis showed that exercise, as an adjunct to standard care, significantly improved postprandial glycaemic control (MD -0.33mmol/L, 95% CI -0.49 to -0.17) and lowered fasting blood glucose (MD -0.31 mmol/L, 95% CI -0.56 to -0.05) when compared with standard care alone, with no increase in adverse events. Effects of similar magnitude were found for aerobic and resistance exercise programs, if performed at a moderate intensity or greater, for 20 to 30minutes, three to four times per week. Meta-analysis did not show that exercise significantly reduced the requirement for insulin. All studies reported that complications or other adverse events were either similar or reduced with exercise.

CONCLUSION

Aerobic or resistance exercise, performed at a moderate intensity at least three times per week, safely helps to control postprandial blood glucose levels and other measures of glycaemic control in women diagnosed with gestational diabetes mellitus.

REGISTRATION

PROSPERO CRD42015019106. [Harrison AL, Shields N, Taylor NF, Frawley HC (2016) Exercise improves glycaemic control in women diagnosed with gestational diabetes mellitus: a systematic review.Journal of Physiotherapy62: 188-196].

The Effect of Regular Exercise on Insulin Sensitivity in Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis

The purpose of this study was to examine the effect of regular exercise training on insulin sensitivity in adults with type 2 diabetes mellitus (T2DM) using the pooled data available from randomised controlled trials. In addition, we sought to determine whether short-term periods of physical inactivity diminish the exercise-induced improvement in insulin sensitivity. Eligible trials included exercise interventions that involved ≥3 exercise sessions, and reported a dynamic measurement of insulin sensitivity. There was a significant pooled effect size (ES) for the effect of exercise on insulin sensitivity (ES, -0.588; 95% confidence interval [CI], -0.816 to -0.359; P<0.001). Of the 14 studies included for meta-analyses, nine studies reported the time of data collection from the last exercise bout. There was a significant improvement in insulin sensitivity in favour of exercise versus control between 48 and 72 hours after exercise (ES, -0.702; 95% CI, -1.392 to -0.012; P=0.046); and this persisted when insulin sensitivity was measured more than 72 hours after the last exercise session (ES, -0.890; 95% CI, -1.675 to -0.105; P=0.026). Regular exercise has a significant benefit on insulin sensitivity in adults with T2DM and this may persist beyond 72 hours after the last exercise session.

Regulation of glucose dynamics by noninvasive peripheral electrical stimulation in normal and insulin-resistant rats

BACKGROUND

The epidemic nature of type 2 diabetes mellitus (T2DM), along with the downsides of current treatments, has raised the need for therapeutic alternatives.

METHODS

We studied normo-glycemic and high-fat diet (HFD), induced insulin-resistant Wistar Han rats for 2 to 3weeks. Rats received peripheral electrical stimulation (PES) treatment (2Hz/16Hz bursts, 10mA) in their hind limbs for 3min, 3 times per week. Glucose tolerance was evaluated by using a glucose tolerance test at the beginning and again at the end of the study. The effect of an acute PES treatment on metabolic rates of glucose appearance and turnover was measured by using the hyperinsulinemic-euglycemic clamp (HEGC) test.

RESULTS

Repeated PES treatment significantly inhibited the progression of glucose intolerance in normal and insulin-resistant rats and prevented HFD-induced gains in body weight and fat mass. Acute treatment induced a prolonged effect on glucose turnover, as evaluated by the HEGC test. Increased hepatic glucose output was observed during the basal state (P<0.005). Under hyperinsulinemic conditions, PES improved tissue sensitivity to insulin (41.1%, P<0.01), improved suppression of hepatic glucose production (58.9±4.4% vs. 87.1±4.4%, P<0.02) and significantly elevated the rate of glycogenesis (P<0.01), compared with controls.

CONCLUSIONS

The present study indicates that a noninvasive PES treatment of very short duration is sufficiently potent to stimulate glucose utilization and improve hepatic insulin sensitivity in rats. Repeated PES treatment may have a beneficial effect on HFD-induced adiposity and control of body weight.

Are glucose levels, glucose variability and autonomic control influenced by inspiratory muscle exercise in patients with type 2 diabetes? Study protocol for a randomized controlled trial

Background

Physical exercise reduces glucose levels and glucose variability in patients with type 2 diabetes. Acute inspiratory muscle exercise has been shown to reduce these parameters in a small group of patients with type 2 diabetes, but these results have yet to be confirmed in a well-designed study. The aim of this study is to investigate the effect of acute inspiratory muscle exercise on glucose levels, glucose variability, and cardiovascular autonomic function in patients with type 2 diabetes.

Methods/design

This study will use a randomized clinical trial crossover design. A total of 14 subjects will be recruited and randomly allocated to two groups to perform acute inspiratory muscle loading at 2 % of maximal inspiratory pressure (PImax, placebo load) or 60 % of PImax (experimental load).

Discussion

Inspiratory muscle training could be a novel exercise modality to be used to decrease glucose levels and glucose variability.

Trial registration

ClinicalTrials.gov NCT02292810.

Attenuation of Ca2+ homeostasis, oxidative stress, and mitochondrial dysfunctions in diabetic rat heart: insulin therapy or aerobic exercise?

We tested the effects of swimming training and insulin therapy, either alone or in combination, on the intracellular calcium ([Ca(2+)]i) homeostasis, oxidative stress, and mitochondrial functions in diabetic rat hearts. Male Wistar rats were separated into control, diabetic, or diabetic plus insulin groups. Type 1 diabetes mellitus was induced by streptozotocin (STZ). Insulin-treated groups received 1 to 4 UI of insulin daily for 8 wk. Each group was divided into sedentary or exercised rats. Trained groups were submitted to swimming (90 min/day, 5 days/wk, 8 wk). [Ca(2+)]i transient in left ventricular myocytes (LVM), oxidative stress in LV tissue, and mitochondrial functions in the heart were assessed. Diabetes reduced the amplitude and prolonged the times to peak and to half decay of the [Ca(2+)]i transient in LVM, increased NADPH oxidase-4 (Nox-4) expression, decreased superoxide dismutase (SOD), and increased carbonyl protein contents in LV tissue. In isolated mitochondria, diabetes increased Ca(2+) uptake, susceptibility to permeability transition pore (MPTP) opening, uncoupling protein-2 (UCP-2) expression, and oxygen consumption but reduced H2O2 release. Swimming training corrected the time course of the [Ca(2+)]i transient, UCP-2 expression, and mitochondrial Ca(2+) uptake. Insulin replacement further normalized [Ca(2+)]i transient amplitude, Nox-4 expression, and carbonyl content. Alongside these benefits, the combination of both therapies restored the LV tissue SOD and mitochondrial O2 consumption, H2O2 release, and MPTP opening. In conclusion, the combination of swimming training with insulin replacement was more effective in attenuating intracellular Ca(2+) disruptions, oxidative stress, and mitochondrial dysfunctions in STZ-induced diabetic rat hearts.

Association between cardiorespiratory fitness and the determinants of glycemic control across the entire glucose tolerance continuum

OBJECTIVE

Cardiorespiratory fitness (VO2max) is associated with glycemic control, yet the relationship between VO2max and the underlying determinants of glycemic control is less clear. Our aim was to determine whether VO2max is associated with insulin sensitivity, insulin secretion, and the disposition index, a measure of compensatory pancreatic β-cell insulin secretion relative to insulin sensitivity, in subjects representing the entire range of the glucose tolerance continuum.

RESEARCH DESIGN AND METHODS

A cohort of subjects (N = 313) with heterogeneous age, sex, BMI, and glycemic control underwent measurements of body composition, HbA1c, fasting glucose, oral glucose tolerance (OGTT), and VO2max. OGTT-derived insulin sensitivity (SiOGTT), glucose-stimulated insulin secretion (GSISOGTT), and the disposition index (DIOGTT) (the product of SiOGTT and GSISOGTT) were measured, and associations between VO2max and these determinants of glycemic control were examined.

RESULTS

A low VO2max was associated with high HbA1c (r = -0.33), high fasting glucose (r = -0.34), high 2-h OGTT glucose (r = -0.33), low SiOGTT (r = 0.73), and high early-phase (r = -0.34) and late-phase (r = -0.36) GSISOGTT. Furthermore, a low VO2max was associated with low early- and late-phase DIOGTT (both r = 0.41). Interestingly, relationships between VO2max and either glycemic control or late-phase GSISOGTT deteriorated across the glucose tolerance continuum.

CONCLUSIONS

The association between poor cardiorespiratory fitness and compromised pancreatic β-cell compensation across the entire glucose tolerance continuum provides additional evidence highlighting the importance of fitness in protection against the onset of a fundamental pathophysiological event that leads to type 2 diabetes.

[Impact of the activation of intention to perform physical activity in type II diabetics: a randomized clinical trial]

Type II diabetes mellitus is a highly prevalent disease among the adult Brazilian population, and one that can be controlled by interventions such as physical activity, among others. The aim of this randomized controlled study was to evaluate the impact of a traditional motivational strategy, associated with the activation of intention theory, on adherence to physical activity in patients with type II, diabetes mellitus who are part of the Unified Health System (SUS). Participants were divided into a control group (CG) and an intervention group (IG). In both groups, the traditional motivational strategy was applied, but the activation of intention strategy was only applied to the IG Group. After a two-month follow-up, statistically significant differences were verified between the groups, related to the practice of walking (p = 0.0050), number of days per week (p = 0.0076), minutes per day (p = 0.0050) and minutes walking per week (p = 0.0015). At the end of the intervention, statistically significant differences in abdominal circumference (p = 0.0048) between the groups were observed. The conclusion drawn is that the activation of intention strategy had greater impact on adherence to physical activity and reduction in abdominal circumference in type II diabetics, than traditional motivational strategy.