Two weekly sessions of combined aerobic and resistance exercise are sufficient to provide beneficial effects in subjects with Type 2 diabetes mellitus and metabolic syndrome

The Impact of Resistance Exercise Training on Glycemic Control Among Adults with Type 2 Diabetes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background: The prevalence of type 2 diabetes mellitus (T2DM) presents a challenge for health organizations because of its high likelihood of morbidity and mortality. There is an increasing body of evidence exploring the efficacy of resistance training (RT) alone on glycemic control. Objective: To update the effectiveness of RT on glycosylated hemoglobin (HbA1c) and fasting glucose in adults diagnosed with T2DM. Methods: CINAHL (EBSDCO), PubMed, MEDLINE (Ovid), and EMBASE (Ovid) databases were searched from inception to 30 January 2024. Published randomized controlled trials (RCTs) of adult humans with T2DM assessing the impact of RT on HbA1c and fasting glucose compared with control condition were included. Data were pooled by the inverse-variance method and reported as mean differences (MDs) with 95% confidence intervals (CIs). Results: Forty-six RCTs totaling 2130 participants met the inclusion criteria. Meta-analysis demonstrated RT significantly reduced HbA1c (MD -0.50% [95% CI, -0.67, -0.34 %], p < .00,001) and fasting glucose (MD -12.03 mg/dl [95% CI, -19.36, -4.69 mg/dl], p = .001). Subgroup analyses found that exercise training durations, gender, and risk of bias had statistically significant effects on HbA1c levels and fasting glucose concentrations after resistance training. However, meta-regression analyses revealed that variables including year of publication, number of sessions per week, mean sample age, sample size, and study quality scores did not significantly affect the change in either HbA1c or glucose. Conclusion: Our meta-analysis with meta-regression delivers further evidence that RT programs are effective approach in attenuation of HbA1c and fasting glucose in individuals with T2DM.

Effects of 12-Week Combined Strength and Endurance Circuit Training Program on Insulin Sensitivity and Retinol-Binding Protein 4 in Women with Insulin-Resistance and Overweight or Mild Obesity: A Randomized Controlled Trial

Background

Circuit training is an exercise mode, that may include both endurance and resistance components. There are premises that a combination of these two modalities brings additional benefits, particularly in improving insulin sensitivity. The retinol-binding protein 4 (RBP4) may inhibit signaling from insulin metabolic pathways in skeletal muscles, thus developing insulin resistance. This study aimed to evaluate whether moderate intensity circuit training combining strength and endurance exercise induces changes in tissue insulin sensitivity, carbohydrate and lipid metabolism, and serum RBP4 levels in insulin-resistant women.

Methods

In this clinical controlled trial women diagnosed with insulin-resistance were randomly divided into two groups. The training group (T) performed circuit training combining strength (50%-80%1RM) and endurance (50%-75%HRR) exercise on five weight and two cardio machines, for 33 minutes, three times per week, for 3 months. Women from the control non-training group (NT) did not change their previous physical activity. At the beginning of the study and after the intervention period, a one-repetition maximum, body mass, and composition, resting heart rate (HR), blood pressure, glucose, insulin, blood lipids, thyroid-stimulating hormone (TSH), insulin-like growth factor-1 (IGF-1), RBP4, and insulin resistance (HOMA-IR) were measured. The results of 27 patients were analyzed using a two-way repeated measures ANOVA.

Results

Significant differences in the pattern of change over time between the groups for resting HR (p < 0.010) and total lean mass (p < 0.039) were found. No differences in HOMA-IR, and RBP4 were observed post-study compared to pre-study in the T group. A significant correlation between RBP4 and TSH concentration was found.

Conclusion

Twelve-week circuit training combining strength and endurance exercise has minor effects on HOMA-IR, glucose and lipid metabolism, IGF-1, TSH, and RBP4. Although moderate-intensity circuit training is considered safe, its effectiveness in patients with overweight and mild obesity may be insufficient to reduce insulin resistance.

Trial Registration

ClinicalTrials.gov: NCT04528693, registered August 23, 2020.

The effects of aerobic exercise on liver function, insulin resistance, and lipid profiles in prediabetic and type 2 diabetic mice

BACKGROUND AND AIMS

The purpose of the current study was to evaluate the expression of gluconeogenesis and insulin resistance key genes; including insulin receptor substrate 1 (Irs1), a serine/threonine protein kinase (Akt), forkhead box class-O 1 (FoxO1) and phosphoenolpyruvate carboxykinase (Pepck) genes, and lipid profiles following either a standard or a high-fat diet (HFD) and either an aerobic exercise or non-exercise intervention in prediabetic and type 2 diabetic (T2DM) mice.

METHODS

24 male mice were randomly assigned to two groups fed with a normal diet (ND) or a HFD for 12 weeks. The mice in each group were again randomly assigned to two groups to create four groups in total: 1. Prediabetes-exercised (Prediabetes-Exe), 2. Prediabetes-non exercised (Prediabetes-Non exe), 3. Healthy-exercised (Healthy-Exe), and 4. Healthy-non exercised (Healthy-Non exe). Eighteen additional male mice were fed with the HFD for 8 weeks, after which streptozotocin (STZ) was administered. The mice were then fed the HFD for an additional 4 weeks. These T2DM mice were then randomly divided into two groups: 1. Diabetes-exercised (Diabetic-Exe), and 2. Diabetes-Non exe. The three Exe groups all exercised on a treadmill for 8 weeks for 5 sessions/week. After the last training session, liver tissue was extracted, and the expression of Irs1, Akt, FoxO1, and Pepck genes was measured using real time quantitative Polymerase chain reaction tests. Lipid profiles were measured in serum and in the liver.

RESULTS

The expression of both Irs1 and Akt was significantly increased in the Healthy-Exe, Prediabetes-Exe, and Diabetes-Exe groups as compared to the Healthy-Non exe, Prediabetes-Non exe, and Diabetes-Non exe groups (p < 0.001). Additionally, the expression of FoxO1 (p < 0.05) and Pepck (p < 0.001) decreased significantly in the Prediabetes-Exe, and Diabetes-Exe groups as compared to the Prediabetes-non exe, and Diabetes-Non exe groups. Aerobic exercise did not lead to reductions in FoxO1 or Pepck expression in the Healthy-Exe mice.

CONCLUSIONS

Eight weeks of aerobic exercise (5 sessions/week) significantly increased the expression of key genes that are important for maintaining glucose homeostasis and improving insulin resistance (Irs1 and Akt), and decreased expression of genes that are important for decreasing gluconeogenesis in the liver (FoxO1 and Pepck) in healthy, prediabetic, and T2DM mice. The lipid profiles improved in healthy, prediabetic, and T2DM mice.

Effectiveness of a real-life program (DIAfit) to promote physical activity in patients with type 2 diabetes: a pragmatic cluster randomized clinical trial

Introduction

The aim of this study was to evaluate the effectiveness of a real-life clinical physical activity program (DIAfit) on improving physical fitness, body composition, and cardiometabolic health in an unselected population with type 2 diabetes mellitus, and to compare the effects of two variants a different exercise frequencies on the same outcomes.

Research design and methods

This was a cluster randomized-controlled assessor-blind trial conducted in 11 clinical centres in Switzerland. All participants in the clinical program with type 2 diabetes were eligible and were randomized to either standard (3 sessions/week for 12 weeks) or alternative (1 session/week for the first four weeks, then 2 sessions/week for the rest of 16 weeks) physical activity program each consisting of 36 sessions of combined aerobic and resistance exercise. Allocation was concealed by a central office unrelated to the study. The primary outcome was aerobic fitness. Secondary outcome measures included: body composition, BMI, HbA_1c, muscle strength, walking speed, balance, flexibility, blood pressure, lipid profile.

Results

All 185 patients with type 2 diabetes (mean age 59.7 +-10.2 years, 48% women) agreed to participate and were randomized in two groups: a standard group (n=88) and an alternative group (n=97)). There was an 11% increase in aerobic fitness after the program (12.5 Watts; 95% CI 6.76 to 18.25; p<0.001). Significant improvements in physical fitness, body composition, and cardiometabolic parameters were observed at the end of the DIAfit program (improvements between 2-29%) except for lean body mass, triglycerides and cholesterol. No differences were observed between both programs, except for a larger weight reduction of -0.97kg (95% CI -0.04 to -1.91; p=0.04) in the standard program.

Conclusions

Both frequency variants of the nation-wide DIAfit program had beneficial effects on physical fitness, HbA_1c, body composition, and blood pressure in type 2 diabetes patients and differences were negligible.

Clinical trial registration

clinicaltrials.gov, identifier NCT01289587.

Effect of exercise training on insulin-stimulated glucose disposal: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND OBJECTIVE

The effect of exercise training on whole-body insulin sensitivity has not been systematically summarized. We aimed to summarize the data from randomized controlled trials evaluating the effect of exercise training on insulin action, in adults.

SUBJECTS

MEDLINE, EMBASE, and CENTRAL databases were searched until January 2021. Randomized controlled trials lasting ≥4 weeks, including adults, and evaluating the effect of exercise on insulin-stimulated glucose disposal measured using the hyperinsulinemic euglycemic clamp, were included.

METHODS

Three reviewers extracted summary data from published trials. The primary outcome was insulin-stimulated glucose disposal. Standardized weighted mean differences (SMD) in glucose disposal between intervention and control were compared. The PEDro scale was used to assess risk of bias.

RESULTS

We included 25 trials (36 interventions, N = 851). Exercise increased insulin-stimulated glucose disposal relative to control, SMD = 0.52 (95% confidence interval [CI]: 0.39, 0.65; p < 0.001; I2 = 47%) without significantly suppressing hepatic glucose production. In trials without isotopic tracers, exercise increased glucose disposal (SMD = 0.63; 95% CI: 0.48, 0.77; p < 0.001, I2 = 55%). In trials with isotopic tracers, exercise increased glucose disposal only when tracers were added to the exogenous glucose used for clamping (SMD = 0.34; 95% CI: 0.03, 0.66, p = 0.034. I2 = 0%). In a meta-regression model including aerobic exercise, weight change, and tracer technique, only percent weight change explained between trial heterogeneity (β = 0.069; 95% CI: 0.005, 0.013). The PEDro rating indicated relatively low risk of bias (5.8 ± 0.22).

CONCLUSIONS

Exercise training for at least four weeks significantly increases insulin-stimulated glucose disposal. Weight loss maximizes the effect and may be needed to improve hepatic insulin sensitivity. Differences in tracer methodology contribute to divergent outcomes and should be considered when assessing conclusions from research examining the effect of exercise on insulin action.

REGISTRATION

PROSPERO (CRD42019124381).

Genes controlling skeletal muscle glucose uptake and their regulation by endurance and resistance exercise

Exercise improves the insulin sensitivity of glucose uptake in skeletal muscle. Due to that, exercise has become a cornerstone treatment for type 2 diabetes mellitus (T2DM). The mechanisms by which exercise improves skeletal muscle insulin sensitivity are, however, incompletely understood. We conducted a systematic review to identify all genes whose gain or loss of function alters skeletal muscle glucose uptake. We subsequently cross-referenced these genes with recently generated data sets on exercise-induced gene expression and signaling. Our search revealed 176 muscle glucose-uptake genes, meaning that their genetic manipulation altered glucose uptake in skeletal muscle. Notably, exercise regulates the expression or phosphorylation of more than 50% of the glucose-uptake genes or their protein products. This included many genes that previously have not been associated with exercise-induced insulin sensitivity. Interestingly, endurance and resistance exercise triggered some common but mostly unique changes in expression and phosphorylation of glucose-uptake genes or their protein products. Collectively, our work provides a resource of potentially new molecular effectors that play a role in the incompletely understood regulation of muscle insulin sensitivity by exercise.

Interactions between insulin and exercise

The interaction between insulin and exercise is an example of balancing and modifying the effects of two opposing metabolic regulatory forces under varying conditions. While insulin is secreted after food intake and is the primary hormone increasing glucose storage as glycogen and fatty acid storage as triglycerides, exercise is a condition where fuel stores need to be mobilized and oxidized. Thus, during physical activity the fuel storage effects of insulin need to be suppressed. This is done primarily by inhibiting insulin secretion during exercise as well as activating local and systemic fuel mobilizing processes. In contrast, following exercise there is a need for refilling the fuel depots mobilized during exercise, particularly the glycogen stores in muscle. This process is facilitated by an increase in insulin sensitivity of the muscles previously engaged in physical activity which directs glucose to glycogen resynthesis. In physically trained individuals, insulin sensitivity is also higher than in untrained individuals due to adaptations in the vasculature, skeletal muscle and adipose tissue. In this paper, we review the interactions between insulin and exercise during and after exercise, as well as the effects of regular exercise training on insulin action.

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

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

Novel Insights into the Pathogenesis and Management of the Metabolic Syndrome

The metabolic syndrome, by definition, is not a disease but is a clustering of individual metabolic risk factors including abdominal obesity, hyperglycemia, hypertriglyceridemia, hypertension, and low high-density lipoprotein cholesterol levels. These risk factors could dramatically increase the prevalence of type 2 diabetes and cardiovascular disease. The reported prevalence of the metabolic syndrome varies, greatly depending on the definition used, gender, age, socioeconomic status, and the ethnic background of study cohorts. Clinical and epidemiological studies have clearly demonstrated that the metabolic syndrome starts with central obesity. Because the prevalence of obesity has doubly increased worldwide over the past 30 years, the prevalence of the metabolic syndrome has markedly boosted in parallel. Therefore, obesity has been recognized as the leading cause for the metabolic syndrome since it is strongly associated with all metabolic risk factors. High prevalence of the metabolic syndrome is not unique to the USA and Europe and it is also increasing in most Asian countries. Insulin resistance has elucidated most, if not all, of the pathophysiology of the metabolic syndrome because it contributes to hyperglycemia. Furthermore, a major contributor to the development of insulin resistance is an overabundance of circulating fatty acids. Plasma fatty acids are derived mainly from the triglycerides stored in adipose tissues, which are released through the action of the cyclic AMP-dependent enzyme, hormone sensitive lipase. This review summarizes the latest concepts in the definition, pathogenesis, pathophysiology, and diagnosis of the metabolic syndrome, as well as its preventive measures and therapeutic strategies in children and adolescents.

Not a Painless Condition: Rheumatological and Musculoskeletal Symptoms in Type 2 Diabetes, and the Implications for Exercise Participation

OBJECTIVES

People with type 2 diabetes (T2D) are more likely to develop a range of rheumatological and musculoskeletal symptoms (RMS), and experience both chronic and widespread pain, compared with the general population. However, these symptoms are not commonly acknowledged by researchers, which hampers our understanding of the impact on this population. Since exercise is a key lifestyle management strategy for T2D and participation levels are typically low, understanding the potential impact of RMS on exercise participation is critical. The aim of this review is to summarise the literature regarding the prevalence and pathophysiology of RMS in T2D, the evidence for the benefits and risks associated with exercise on RMS, and the currently available tools for the reporting of RMS in both research studies and community settings.

METHODS

A narrative review.

RESULTS

There are numerous exercise trials in T2D, but few have sufficiently reported pain-related adverse events and even fewer have investigated the effects of exercise on RMS and chronic pain.

DISCUSSION

Recommendations for future research are provided.

Rho GTPases-Emerging Regulators of Glucose Homeostasis and Metabolic Health

Rho guanosine triphosphatases (GTPases) are key regulators in a number of cellular functions, including actin cytoskeleton remodeling and vesicle traffic. Traditionally, Rho GTPases are studied because of their function in cell migration and cancer, while their roles in metabolism are less documented. However, emerging evidence implicates Rho GTPases as regulators of processes of crucial importance for maintaining metabolic homeostasis. Thus, the time is now ripe for reviewing Rho GTPases in the context of metabolic health. Rho GTPase-mediated key processes include the release of insulin from pancreatic β cells, glucose uptake into skeletal muscle and adipose tissue, and muscle mass regulation. Through the current review, we cast light on the important roles of Rho GTPases in skeletal muscle, adipose tissue, and the pancreas and discuss the proposed mechanisms by which Rho GTPases act to regulate glucose metabolism in health and disease. We also describe challenges and goals for future research.

Resistance Exercise Intensity is Correlated with Attenuation of HbA1c and Insulin in Patients with Type 2 Diabetes: A Systematic Review and Meta-Analysis

We investigated the influence of resistance exercise (RE) with different intensities on HbA1c, insulin and blood glucose levels in patients with type 2 diabetes (T2D). Diabetes trials that compared RE group with a control were included in meta-analysis. Exercise intensities were categorized into low-to-moderate-intensity and high-intensity subgroups. Intensity effect on glycemic control was determined by meta-regression analysis, and risk-of-bias was assessed using Cochrane Collaboration tool. 24 trials met the inclusion criteria, comprised of 962 patients of exercise (n = 491) and control (n = 471). Meta-regression analysis showed decreased HbA1c (p = 0.006) and insulin (p = 0.015) after RE was correlated with intensity. Subgroup analysis revealed decreased HbA1c was greater with high intensity (−0.61; 95% CI −0.90, −0.33) than low-to-moderate intensity (−0.23; 95% CI −0.41, −0.05). Insulin levels were significantly decreased only with high intensity (−4.60; 95% CI −7.53, −1.67), not with low-to-moderate intensity (0.07; 95% CI −3.28, 3.42). Notably, values between the subgroups were statistically significant for both HbA1c (p = 0.03) and insulin (p = 0.04), indicative of profound benefits of high-intensity RE. Pooled outcomes of 15 trials showed only a decreased trend in blood glucose with RE (p = 0.09), and this tendency was not associated with intensity. Our meta-analysis provides additional evidence that high-intensity RE has greater beneficial effects than low-to-moderate-intensity in attenuation of HbA1c and insulin in T2D patients.

Aerobic exercise regulates blood lipid and insulin resistance via the toll‑like receptor 4‑mediated extracellular signal‑regulated kinases/AMP‑activated protein kinases signaling pathway

Diabetes mellitus is a complicated metabolic disease with symptoms of hyperglycemia, insulin resistance, chronic damage and dysfunction of tissues, and metabolic syndrome for insufficient insulin production. Evidence has indicated that exercise treatments are essential in the progression of type‑ІІ diabetes mellitus, and affect insulin resistance and activity of islet β‑cells. In the present study, the efficacy and signaling mechanism of aerobic exercise on blood lipids and insulin resistance were investigated in the progression of type‑ІІ diabetes mellitus. Body weight, glucose metabolism and insulin serum levels were investigated in mouse models of type‑ІІ diabetes mellitus following experienced aerobic exercise. Expression levels of inflammatory factors, interleukin (IL)‑6, high‑sensitivity C‑reactive protein, tumor necrosis factor‑α and leucocyte differentiation antigens, soluble CD40 ligand in the serum were analyzed in the experimental mice. In addition, expression levels of toll‑like receptor 4 (TLR‑4) were analyzed in the liver cells of experimental mice. Changes of oxidative stress indicators, including reactive oxygen species, superoxide dismutase, glutathione and catalase were examined in the liver cells of experimental mice treated by aerobic exercise. Expression levels and activity of extracellular signal‑regulated kinases (ERK) and AMP‑activated protein kinase (AMPK) signaling pathways were investigated in the liver cells of mouse models of type‑ІІ diabetes mellitus after undergoing aerobic exercise. Aerobic exercise decreased the expression levels of inflammatory factors in the serum of mouse models of type‑ІІ diabetes mellitus. The results indicated that aerobic exercise downregulated oxidative stress indicators in liver cells from mouse models of type‑ІІ diabetes mellitus. In addition, the ERK and AMPK signaling pathways were inactivated by aerobic exercise in liver cells in mouse models of type‑ІІ diabetes mellitus. The activity of ERK and AMPK, and the function of islet β‑cells were observed to be improved in experimental mice treated with aerobic exercise. Furthermore, blood lipid metabolism and insulin resistance were improved by treatment with aerobic exercise. Body weight and glucose concentration of serology was markedly improved in mouse models of type‑ІІ diabetes mellitus. Furthermore, TLR‑4 inhibition markedly promoted ERK and AMPK expression levels and activity. Thus, these results indicate that aerobic exercise may improve blood lipid metabolism, insulin resistance and glucose plasma concentration in mouse models of type‑ІІ diabetes mellitus. Thus indicating aerobic exercise is beneficial for improvement of blood lipid and insulin resistance via the TLR‑4‑mediated ERK/AMPK signaling pathway in the progression of type‑ІІ diabetes mellitus.

Supplementation with Hualian No. 4 wild bitter gourd (Momordica charantia Linn. var. abbreviata ser.) extract increases anti-fatigue activities and enhances exercise performance in mice

Hualian No. 4 wild bitter gourd (WBG) is a specific vegetable cultivated by the Hualien District Agricultural Research and Extension Station in Taiwan. WBG is commonly consumed as a vegetable and used as a popular folk medicine. However, few studies have demonstrated the effects of WBG supplementation on exercise performance, physical fatigue and the biochemical profile. The purpose of this study was to evaluate the potential beneficial effects of WBG extract on fatigue and ergogenic functions following physiological challenge. Three groups of male ICR mice (n=8 per group) were orally administered 0, 1 or 2.5 g/kg/day of WBG for 4 weeks. They were respectively designated the vehicle, WBG-1X and WBG-2.5X groups. WBG significantly decreased body weight (BW) and epididymal fat pad (EFP) weight. Concerning physical performance, WBG supplementation dose-dependently increased grip strength and endurance swimming time. Concerning anti-fatigue activity, WBG decreased levels of serum lactate, ammonia, creatine kinase and blood urea nitrogen, and economized glucose metabolism after acute exercise challenge. Glycogen in the liver and gastrocnemius muscle dose-dependently increased with WBG treatment. Concerning the biochemical profile, WBG treatment significantly decreased alanine aminotransferase (ALT), blood urea nitrogen (BUN) and urea acid (UA), and increased total protein (TP). Therefore, 4-week supplementation with WBG may decrease white adipose weight, enhance energy economy, increase glycogen storage to enhance exercise performance and reduce fatigue.

Exercise-stimulated glucose uptake - regulation and implications for glycaemic control

Skeletal muscle extracts glucose from the blood to maintain demand for carbohydrates as an energy source during exercise. Such uptake involves complex molecular signalling processes that are distinct from those activated by insulin. Exercise-stimulated glucose uptake is preserved in insulin-resistant muscle, emphasizing exercise as a therapeutic cornerstone among patients with metabolic diseases such as diabetes mellitus. Exercise increases uptake of glucose by up to 50-fold through the simultaneous stimulation of three key steps: delivery, transport across the muscle membrane and intracellular flux through metabolic processes (glycolysis and glucose oxidation). The available data suggest that no single signal transduction pathway can fully account for the regulation of any of these key steps, owing to redundancy in the signalling pathways that mediate glucose uptake to ensure maintenance of muscle energy supply during physical activity. Here, we review the molecular mechanisms that regulate the movement of glucose from the capillary bed into the muscle cell and discuss what is known about their integrated regulation during exercise. Novel developments within the field of mass spectrometry-based proteomics indicate that the known regulators of glucose uptake are only the tip of the iceberg. Consequently, many exciting discoveries clearly lie ahead.

The pleiotropic effect of physical exercise on mitochondrial dynamics in aging skeletal muscle

Decline in human muscle mass and strength (sarcopenia) is one of the principal hallmarks of the aging process. Regular physical exercise and training programs are certain powerful stimuli to attenuate the physiological skeletal muscle alterations occurring during aging and contribute to promote health and well-being. Although the series of events that led to these muscle adaptations are poorly understood, the mechanisms that regulate these processes involve the “quality” of skeletal muscle mitochondria. Aerobic/endurance exercise helps to maintain and improve cardiovascular fitness and respiratory function, whereas strength/resistance-exercise programs increase muscle strength, power development, and function. Due to the different effect of both exercises in improving mitochondrial content and quality, in terms of biogenesis, dynamics, turnover, and genotype, combined physical activity programs should be individually prescribed to maximize the antiaging effects of exercise.

Mechanisms governing the health and performance benefits of exercise

Humans are considered among the greatest if not the greatest endurance land animals. Over the last 50 years, as the population has become more sedentary, rates of cardiovascular disease and its associated risk factors such as obesity, type 2 diabetes and hypertension have all increased. Aerobic fitness is considered protective for all-cause mortality, cardiovascular disease, a variety of cancers, joint disease and depression. Here, I will review the emerging mechanisms that underlie the response to exercise, focusing on the major target organ the skeletal muscle system. Understanding the mechanisms of action of exercise will allow us to develop new therapies that mimic the protective actions of exercise.

Physical and immunological aspects of exercise in chronic diseases

Physical inactivity and sedentary lifestyles are believed to be independent risk factors for the occurrence of numerous diseases, including, obesity, Type 2 diabetes, metabolic syndrome, cardiovascular disease, cancer and mental health, all leading to substantial morbidity and/or premature death. It has been found that regular exercise, is associated with better quality of life and health outcomes, and reduces the risk of cardiovascular disease and cancer. Here, we review the effects regular exercise has on mental health and well-being, on the immune system and in cancer, cardiovascular disease, autoimmunity and metabolic syndrome. Is exercise the new immunotherapy to treat diseases?

Impact of resistance circuit training on neuromuscular, cardiorespiratory and body composition adaptations in the elderly

Declines in maximal aerobic power and skeletal muscle force production with advancing age are examples of functional declines with aging, which can severely limit physical performance and independence, and are negatively correlated with all cause mortality. It is well known that both endurance exercise and resistance training can substantially improve physical fitness and health-related factors in older individuals. Circuit-based resistance training, where loads are lifted with minimal rest, may be a very effective strategy for increasing oxygen consumption, pulmonary ventilation, strength, and functional capacity while improving body composition. In addition, circuit training is a time-efficient exercise modality that can elicit demonstrable improvements in health and physical fitness. Hence, it seems reasonable to identify the most effective combination of intensity, volume, work to rest ratio, weekly frequency and exercise sequence to promote neuromuscular, cardiorespiratory and body composition adaptations in the elderly. Thus, the purpose of this review was to summarize and update knowledge about the effects of circuit weight training in older adults and elderly population, as a starting point for developing future interventions that maintain a higher quality of life in people throughout their lifetime.

Low-volume exercise can prevent sucrose-induced weight gain but has limited impact on metabolic measures in rats

PURPOSE

Rats given sugar-sweetened drinks can develop glucose intolerance, insulin resistance and dyslipidaemia. The aim of this study was to investigate whether such metabolic disruptions and also possible weight gain induced by chronic sucrose consumption could be attenuated by low-volume exercise.

METHODS

Using a 2 × 2 factorial design, rats were given free access for 57 days to either a 10% sucrose solution (Suc and SucEx) or water only (Con and ConEx), while exercise rats (SucEx and ConEx) received 20-min treadmill training every 3 days. Caloric intake and body weight were measured throughout this dietary intervention. Oral glucose tolerance tests were performed on days 29 and 54. Plasma insulin, triglycerides and leptin were also measured, together with post-mortem measures of retroperitoneal fat pads and liver triglycerides.

RESULTS

In groups given sucrose, exercise reduced calorie consumption, reduced weight gain and decreased leptin relative to non-exercised controls. Exercise was found to improve glucose tolerance and insulin action at day 29, but not day 54.

CONCLUSIONS

Low-volume exercise can be effective in preventing weight gain in sucrose-fed rats, probably via reduction of subcutaneous fat, but prevention of the glucose intolerance and dyslipidaemia produced by sucrose consumption may be transient.

Combined exercise for people with type 2 diabetes mellitus: a systematic review

Type 2 diabetes mellitus has emerged as a major non-communicable chronic diseases in many countries. The importance of exercise in the prevention and management of this disease is evident. This paper briefly reviews the effects of combining aerobic and resistance exercises on glycemic control, and details the training and characteristics of various interventions in adults with type 2 diabetes mellitus. Literature searches were performed using electronic databases between the 1st of January 1950 and the 15th of September 2011. Of the 403 articles retrieved, 28 studies met our inclusion criteria. Combined exercise protocols seem to improve glycemic control to a greater extent than isolated forms of exercise. Nevertheless, length, duration, intensity, mode, number of exercises, sets and repetitions varied markedly among studies. Supervised training sessions, recommended structured exercises, and splitting aerobic and resistance training in separate sessions may be relevant for best results. Future studies should analyze the effects of different aerobic and resistance training modes, different training and progression methods, and whether one type of exercise is optimal, as these issues are likely to convey greater knowledge on type 2 diabetes mellitus management through combined exercise.

An innovative model for changing the lifestyles of persons with obesity and/or Type 2 diabetes mellitus

AIM

To describe the multidisciplinary lifestyle intervention model used in an experimental CURIAMO (Centro Universitario Ricerca Interdipartimentale Attività Motoria) project designed to validate the short- and long-term efficacy of the model in obesity and Type 2 diabetes.

RESEARCH DESIGN AND METHODS

Over a 3-yr period, about 1000 adults (70% diabetes-free and overweight or obese; 30% with Type 2 diabetes and overweight or obese).

INCLUSION CRITERIA

Age range 18-80 yr, body mass index >27 kg/m2 with or without Type 2 diabetes mellitus; participants will be divided into three age groups (18-45, 45-65, 65-80 yr). The study duration will be from 5 to 6 yr: 1 yr of intervention followed by a mean follow-up period of 4 yr. In the first years, after a 4- month intensive lifestyle intervention, subjects will follow a maintenance programme. The intervention, which includes seven steps, involves the following experts: endocrinologists, sport medicine doctors or cardiologists, psychologists, dietitians, educators, nurses, exercise physiologists, and promoters of outdoor activities.

RESULTS

The main endpoint of the study is to measure the efficacy of the lifestyle improvement intervention, defined as a loss of at least 7% of body weight combined with an increase of at least 10 MET/h-1·week-1 of energy expenditure by physical activity, after 1 yr and during the follow-up. A cost/utility analysis of the model will be made in participants with diabetes.

CONCLUSIONS

We expect that the CURIAMO model will be highly effective, and that the aim of the intervention will be achieved in more than 70% of cases.