The Acute Effects of Interval-Type Exercise on Glycemic Control in Type 2 Diabetes Subjects: Importance of Interval Length. A Controlled, Counterbalanced, Crossover Study

Correlation between circulating microRNAs and vascular biomarkers in type 2 diabetes based upon physical activity: a biochemical analytic study

BACKGROUND

This research investigated how physical activity (PA) might impact the expression of several microRNAs, specifically miR-126, miR-146a, miR-34a, miR-124a, miR-155, and miR-221, in the blood of elderly individuals with type 2 diabetes (T2D). Additionally, the study examined the relationship between these microRNAs and markers of vascular endothelial dysfunction, including vascular endothelial growth factor (VEGF), apolipoprotein A-I (apoA-I), and apolipoprotein B (apoB), to assess their potential in the prevention, early detection, and treatment of diabetes.

METHODS

This correlational observational study involved 100 male participants, aged between 18 and 65 years, all of whom had been living with type 2 diabetes (T2D) for over six years. The participants were divided into three groups: inactive, moderate, and active, depending on their level of physical activity (PA). Real-time PCR and immunoassays were employed to measure the expression of selected miRNAs, as well as VEGF, apoA-I, apoB, and diabetic management indicators. PA levels were determined using ACTi graph GT1M accelerometer (model WAM 7164; Fort Walton Beach, FL) and energy expenditure was measured in the form of metabolic equivalent (MET) by indirect calorimetry method.

RESULTS

The expression levels of miR-146a, miR-34a, and miR-124a were significantly higher in patients with higher physical activity, while no such increase was observed for the other miRNAs in less active participants. Additionally, PA-active individuals showed a more pronounced decrease in fasting blood sugar (FBS), insulin resistance (IR), fasting insulin (FINS), HOMA-IR, HbA1c (%), and levels of VEGF, apoAI, apoB, and the apoB/apoA-I ratio. The alteration in miRNA expression was positively associated with physical activity, VEGF, apoAI, apoB, the apoB/apoA-I ratio, and diabetes-related metrics, while being inversely related to BMI.

CONCLUSIONS

In diabetic patients with higher physical activity levels, circulating miR-146a, miR-34a, and miR-124a showed elevated expression, accompanied by a notable decrease in vascular biomarkers, including apoAI, apoB, and the apoB/apoA-I ratio. The findings revealed a strong correlation between these vascular biomarkers and the physiological responses of miR-146a, miR-34a, and miR-124a, though larger studies are required to validate these results further.

TRIAL REGISTRATION

Not applicable.

Acute effect of aerobic and resistance exercise on glycemia in individuals with type 2 diabetes: Systematic review and meta-analysis

BACKGROUND

Type 2 diabetes (T2D) is the most prevalent in the world population, and exercise is one of the main non-pharmacological interventions to treat this health condition.

OBJECTIVE

To evaluate the effect of a single session of aerobic exercise (AE) and/or resistance exercise (RE) on post-exercise glycemia in individuals with T2D.

METHODS

A literature search was conducted in CINAHL, Cochrane Library, EMBASE, Google Scholar, LILACS, MEDLINE/Ovid, SciELO, SPORTDiscus, and Web of Science up to May 2024, randomized and non-randomized clinical trials were included. The risk of bias and the certainty of evidence were assessed using the Cochrane "Risk of Bias" and GRADE tools, respectively.

RESULTS

Initially, 7210 studies were identified, 26 were included in the systematic review, and 13 in the meta-analysis. A single session of continuous AE (CAE), interval AE (IAE), or RE promoted a significant reduction in glycemia in the first minute after exercise (-1.48 mmol/L [95 % CI:-1.73, -1.23]; -2.66 mmol/L [95 % CI:-3.48, -1.84]; -1.18 mmol/L [95 % CI:-2.15, -0.21], respectively), compared to the control session. This reduction persisted for up to 10 min after the CAE session (-1.61 mmol/L [95 % CI:-2.21, -1.01]) and up to 30 min after the IAE session (-1.11 mmol/L [95 % CI:-1.88, -0.35]). The risk of bias was assessed as uncertain, and the quality of the evidence was moderate.

CONCLUSION

CAE and IAE reduces glycemia for a period of up to 10 or 30 min after its completion, respectively, while a single session of RE reduces glycemia only in the first-minute post-exercise in individuals with T2D.

Health benefits of interval walking training

Interval walking training (IWT) is a free-living training intervention involving alternating fast and slow walking cycles. IWT is efficacious in improving physical fitness and muscle strength, and reducing factors associated with lifestyle-related diseases. In individuals with type 2 diabetes, IWT improves glycemic control directly through enhanced glucose effectiveness, challenging conventional views on mechanisms behind training-induced improvements in glycemic control. Whereas adherence to IWT in short-term studies is high, ensuring long-term adherence remains a challenge, particularly in populations with chronic diseases and/or overweight/obesity. Long-term studies in real-world settings are imperative to ascertain the widespread effectiveness of IWT and elucidate its impact on hard endpoints.

Physical Exercise Methods and Their Effects on Glycemic Control and Body Composition in Adults with Type 2 Diabetes Mellitus (T2DM): A Systematic Review

The prevalence of T2DM represents a challenge for health agencies due to its high risk of morbidity and mortality. Physical Activity (PA) is one of the fundamental pillars for the treatment of T2DM, so Physical Exercise (PE) programs have been applied to research their effectiveness. The objective of the study was to analyze the effects of PE methods on glycemic control and body composition of adults with T2DM. A systematic review without meta-analysis was performed, using the PubMed database. Quasi-experimental and pure experimental clinical trials were included, which were available free of charge and were published during 2010-2020. In the results, 589 articles were found and 25 passed the inclusion criteria. These were classified and analyzed according to the methods identified (AE, IE, RE, COM, and others), duration and variable(s) studied. It is concluded that PE is effective for glycemic control and body composition in adults with T2DM using different methods (AE, IE, RE, COM, and others), both in the short and long term. Adequate organization of PE components such as frequency, duration, volume, and intensity, is essential.

Extraordinary claims in the literature on high-intensity interval training (HIIT): IV. Is HIIT associated with higher long-term exercise adherence?

Nonadherence to and dropout from regular exercise and physical activity are important reasons why the field of exercise science has yet to fulfill its promise of improving public health on a global scale. Researchers have claimed that High-Intensity Interval Training (HIIT) is a feasible and sustainable exercise modality that may result in higher long-term adherence than moderate-intensity continuous exercise. If true, this would be a breakthrough discovery that could unlock the potential of exercise as a health-promoting intervention. We performed a systematic search of the literature and identified eight trials comparing HIIT to moderate-intensity continuous exercise, all of which involved follow-up periods of at least 12 months (i.e., SWIFT, Small Steps for Big Changes, SAINTEX-CAD, SMARTEX-HF, Generation 100, FITR, OptimEx-Clin, HITTS). Findings from these trials demonstrate that, while unsupervised, individuals initially assigned to HIIT tend to exercise at lower-than-prescribed intensities and HIIT groups demonstrate no advantage in long-term adherence.

High-intensity interval exercise versus moderate-intensity continuous exercise on postprandial glucose and insulin responses: A systematic review and meta-analysis

We performed a meta-analysis to investigate the effects of high-intensity interval exercise (HIIE) as compared to moderate-intensity exercise (MIE) and a control condition (CON) on postprandial glucose (PPG) and insulin (PPI) responses. PubMed, Web of Science, and Scopus were comprehensively searched to identify relevant studies until October 2021. Separate analyses were conducted for HIIE versus MIE and HIIE versus CON. A total of 30 studies comprising 36 intervention arms and involving 467 participants (350 adults) were included in the meta-analysis. HIIE reduced PPG and PPI when compared with CON. Based on subgroup analyses, reductions in PPG and PPI were significant for both children and adult participants, as well as for healthy participants and participants with metabolic disorders, with larger effects in those with metabolic disorders. There were no significant differences between HIIE and MIE for PPG or PPI. However, when comparing studies matched for total work performed, HIIE was more effective for decreasing PPG as compared with MIE. HIIE is effective for reducing PPG and PPI in both children and adult participants, particularly in those with metabolic disorders. In addition, HIIE has superior effects for reducing PPG as compared with MIE, when equivalent work was performed at both intensity levels.

Walking for subjects with type 2 diabetes: a systematic review and joint AMD/SID/SISMES evidence-based practical guideline

Aims

Regular exercise is considered a cornerstone in the management of type 2 diabetes mellitus (T2DM). It improves glucose control and cardiovascular risk factors, contributes to weight loss, and also improves general well-being, likely playing a role in the prevention of chronic complications of diabetes. However, compliance to exercise recommendations is generally inadequate in subjects with T2DM. Walking is the most ancestral form of physical activity in humans, easily applicable in daily life. It may represent, in many patients, a first simple step towards lifestyle changes. Nevertheless, while most diabetic patients do not engage in any weekly walking, exercise guidelines do not generally detail how to improve its use. The aims of this document are to conduct a systematic review of available literature on walking as a therapeutic tool for people with T2DM, and to provide practical, evidence-based clinical recommendations regarding its utilization in these subjects.

Data synthesis

Analysis of available RCTs proved that regular walking training, especially when supervised, improves glucose control in subjects with T2DM, with favorable effects also on cardiorespiratory fitness, body weight, and blood pressure. Moreover, some recent studies have shown that even short bouts of walking, used for breaking prolonged sitting, can ameliorate glucose profiles in diabetic patients with sedentary behavior.

Conclusions

There is sufficient evidence to recognize that walking is a useful therapeutic tool for people with T2DM. This document discusses theoretical and practical issues for improving its use.

Walking for subjects with type 2 diabetes: A systematic review and joint AMD/SID/SISMES evidence-based practical guideline

AIMS

Regular exercise is considered a cornerstone in the management of type 2 diabetes mellitus (T2DM). It improves glucose control and cardiovascular risk factors, contributes to weight loss, and also improves general well-being, likely playing a role in the prevention of chronic complications of diabetes. However, compliance to exercise recommendations is generally inadequate in subjects with T2DM. Walking is the most ancestral form of physical activity in humans, easily applicable in daily life. It may represent, in many patients, a first simple step towards lifestyle changes. Nevertheless, while most diabetic patients do not engage in any weekly walking, exercise guidelines do not generally detail how to improve its use. The aims of this document are to conduct a systematic review of available literature on walking as a therapeutic tool for people with T2DM, and to provide practical, evidence-based clinical recommendations regarding its utilization in these subjects.

DATA SYNTHESIS

Analysis of available RCTs proved that regular walking training, especially when supervised, improves glucose control in subjects with T2DM, with favorable effects also on cardiorespiratory fitness, body weight and blood pressure. Moreover, some recent studies have shown that even short bouts of walking, used for breaking prolonged sitting, can ameliorate glucose profiles in diabetic patients with sedentary behavior.

CONCLUSIONS

There is sufficient evidence to recognize that walking is a useful therapeutic tool for people with T2DM. This document discusses theoretical and practical issues for improving its use. This article is co-published in the journals Sport Sciences for Health and Nutrition, Metabolism and Cardiovascular Diseases.

Exercise-Induced Improvements in Postprandial Glucose Response Are Blunted by Pre-Exercise Hyperglycemia: A Randomized Crossover Trial in Healthy Individuals

BACKGROUND

Exercise improves glycemic control but the magnitude, and in some cases, the direction of this effect is variable. Ambient hyperglycemia has been implicated in this exercise response heterogeneity. The current study investigated whether pre-exercise hyperglycemia directly impacts the effect of exercise on glycemic control.

METHODS

Twelve healthy normal glucose-tolerant males completed four trials in a randomized, crossover design. Each trial consisted of 24-h pre-intervention monitoring, a 7-h intervention, and 24-h post-intervention monitoring. Glycemic control was measured throughout the study by continuous glucose monitoring. The four interventions were no exercise (CON) or 45 min of cycling exercise (70%HRmax) preceded by 3.5 h of either normoglycemia (NG-Ex), steady-state hyperglycemia induced by constant glucose infusion (HG-Ex) or fluctuating glycemia induced by repeated glucose bolus infusions (FG-Ex).

RESULTS

Physical activity and diet were similar between trials, and energy expenditure during exercise was matched between exercise trials (all P > 0.05). Mean glucose during the 3.5 h ± infusion period was higher in HG-Ex (mean ± SEM; 7.2 ± 0.4 mmol/L) and FG-Ex (7.3 ± 0.3 mmol/L) compared to CON (4.8 ± 0.2 mmol/L) and NG-Ex (5.0 ± 0.2 mmol/L) trials (P < 0.01). Glycemic variability was greatest in FG-Ex (P < 0.01). Following the interventions, the postprandial glucose response (iAUC) was reduced by exercise in NG-Ex compared to CON (321.1 ± 38.6 vs. 445.5 ± 49.7 mmol/L.8h, P < 0.05, d=0.81). This benefit was blunted when exercise was preceded by steady-state (HG-Ex, 425.3 ± 45.7 mmol/L.8h) and fluctuating (FG-Ex, 465.5 ± 39.3 mmol/L.8h) hyperglycemia (both P > 0.05 vs. CON).

CONCLUSION

Pre-exercise hyperglycemia blunted the glucoregulatory benefits of acute exercise upon postprandial glucose response, suggesting that exposure to hyperglycemia contributes to exercise response heterogeneity.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, identifier NCT03284216.

Sources of Inter-individual Variability in the Therapeutic Response of Blood Glucose Control to Exercise in Type 2 Diabetes: Going Beyond Exercise Dose

In the context of type 2 diabetes, inter-individual variability in the therapeutic response of blood glucose control to exercise exists to the extent that some individuals, occasionally referred to as “non-responders,” may not experience therapeutic benefit to their blood glucose control. This narrative review examines the evidence and, more importantly, identifies the sources of such inter-individual variability. In doing so, this review highlights that no randomized controlled trial of exercise has yet prospectively measured inter-individual variability in blood glucose control in individuals with prediabetes or type 2 diabetes. Of the identified sources of inter-individual variability, neither has a prospective randomized controlled trial yet quantified the impact of exercise dose, exercise frequency, exercise type, behavioral/environmental barriers, exercise-meal timing, or anti-hyperglycemic drugs on changes in blood glucose control, in individuals with prediabetes or type 2 diabetes. In addition, there is also an urgent need for prospective trials to identify molecular or physiological predictors of inter-individual variability in the changes in blood glucose control following exercise. Therefore, the narrative identifies critical science gaps that must be filled if exercise scientists are to succeed in optimizing health care policy recommendations for type 2 diabetes, so that the therapeutic benefit of exercise may be maximized for all individuals with, or at risk of, diabetes.

Acute strength training promotes responses in whole blood circulating levels of miR-146a among older adults with type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) consists of a set of metabolic and endocrine disorders which evolve into deficiency in insulin action and hyperglycemia. Physical exercise is considered the main intervention to prevent and control T2DM. Literature has suggested that circulating microRNAs (miRs) help to understand responses to physical activity among diabetic patients. Thus, the aim of this study was to analyze the acute effect of two interventions (strength and cardiovascular) on the total, whole blood circulating concentrations of miR-126, miR-146a and miR-155 in older adults with and without T2DM. A total of 23 male and female older adults (68.2±5.3 years) participated in the trial, 13 of whom presented with controlled T2DM and 10 were nondiabetics. They underwent both interventions separately, performed with intensity from 60% to 70% of reserve heart rate. Glucose and miRs levels were quantified and compared across groups with baseline titers as covariables. Diabetic patients showed more reduction in serum blood glucose than nondiabetics, with a great magnitude of reduction after the strength training intervention, which was paralleled by a positive change of the whole blood circulating levels of miR-146a, but not of the other miRs. Our report supports evidence that miR-146a levels in peripheral blood leukocytes are negatively associated with a state of insulin resistance, which is suggested as a novel marker to trace response to antidiabetic interventions.