Influence of physical training on blood glucose control, glucose tolerance, insulin secretion, and insulin action in non-insulin-dependent diabetic patients

Extrinsic and intrinsic modulators of inflammation-resolution signaling in heart failure

Chronic and uncleared inflammation is the root cause of various cardiovascular diseases. Fundamentally, acute inflammation is supportive when overlapping with safe clearance of inflammation termed resolution; however, if the lifestyle-directed extrinsic factors such as diet, sleep, exercise, or physical activity are misaligned, that results in unresolved inflammation. Although genetics play a critical role in cardiovascular health, four extrinsic risk factors-unhealthy processed diet, sleep disruption or fragmentation, sedentary lifestyle, thereby, subsequent stress-have been identified as heterogeneous and polygenic triggers of heart failure (HF), which can result in several complications with indications of chronic inflammation. Extrinsic risk factors directly impact endogenous intrinsic factors, such as using fatty acids by immune-responsive enzymes [lipoxygenases (LOXs)/cyclooxygenases (COXs)/cytochromes-P450 (CYP450)] to form resolution mediators that activate specific resolution receptors. Thus, the balance of extrinsic factors such as diet, sleep, and physical activity feed-forward the coordination of intrinsic factors such as fatty acids-enzymes-bioactive lipid receptors that modulates the immune defense, metabolic health, inflammation-resolution signaling, and cardiac health. Future research on lifestyle- and aging-associated molecular patterns is warranted in the context of intrinsic and extrinsic factors, immune fitness, inflammation-resolution signaling, and cardiac health.

Desk based prompts to replace workplace sitting with stair climbing; a pilot study of acceptability, effects on behaviour and disease risk factors

Background

Prolonged sitting is associated with increased risk of obesity, type 2 diabetes and cardiovascular disease. Occupational sitting accounts for up to 50 h/week for employees. This pilot study assessed the acceptability of stair climbing as an interruption to sitting throughout working hours, and provided preliminary data of the effects on glucose and lipid profiles.

Methods

A quasi-experimental design was conducted involving 16 sedentary office workers (five females and 11 males) for intervention (n = 8) and control groups (n = 8) with mean age of 36.38 (5.58). For the eight-week intervention, a continuous four-floor stair climb and descent was performed eight times/day spread evenly over the working day. A prompt to climb was presented on the participant’s computer eight times/day. Participants in the experimental group recorded daily floors climbed and steps (measured using pedometers) in a weekly log sheet. Blood samples were collected pre and post intervention to test effects on fasting glucose and 2 h plasma glucose, triglycerides, and total (TC), LDL and HDL cholesterol. Experimental participants were interviewed at the end of the study. The Wilcoxon signed rank test was used to compare the median changes (pre-post) of the dependent variables.

Results

On average, the experimental group climbed 121 floors/week when prompted. There were significant reductions in fasting blood glucose, TC and LDL, as well as the derived measures of ‘bad’ cholesterol and the TC/HDL ratio in the experimental group. Post-experimental interviews indicated that the interruption to sitting was well tolerated.

Conclusion

Prompted stair climbing activity had impacts on health outcomes and was found acceptable to employees at work.

Trial registration

Ethics for this study was approved by Science, Technology, Engineering and Mathematics Ethical Review Committee, University of Birmingham with ethics reference number ERN_15_0491.

Supplementary information

The online version contains supplementary material available at 10.1186/s12889-022-14393-1.

The associations between health-related physical fitness and fasting blood glucose in war veterans: a population-based study

The main purpose of the study was to analyze the associations between health-related physical fitness and fasting blood glucose in war veterans. In this cross-sectional study, we recruited 764 men and women aged 45-75 years, who were part of the Homeland War between 1990 and 1995 (33.5% women). Health-related physical fitness included: (1) fat mass and fat-free mass (body composition), (2) push-ups in 30 s (muscular dynamic endurance of upper extremities), (3) sit-ups in 30 s (repetitive upper body strength), (4) chair-stands in 30 s (lower body strength), (5) sit-and-reach test (flexibility) and (6) the 2-min step test (cardiorespiratory function). Laboratory measurement of fasting blood glucose was performed according to standardized procedures in resting seated position after a 12-h overnight fast. Generalized estimating equations with multiple regression models were used to calculate the associations between health-related physical fitness and fasting blood glucose. In men, fasting blood glucose was significantly correlated with fat-free mass (β = - 0.25, p < 0.001), push-ups in 30 s (β = - 0.55, p < 0.001), chair-stands in 30 s (β = - 0.50, p < 0.001), sit-ups in 30 s (r = - 0.45, p < 0.001), the sit-and reach test (r = - 0.46, p < 0.001) and the 2-min step test (r = - 0.19, p < 0.001), while fat mass was positively correlated with fasting blood glucose (β = 0.14, p = 0.004). In women, fasting blood glucose was significantly correlated with fat mass (β = 0.20, p = 0.002), fat-free mass (β = - 0.15, p = 0.014), push-ups in 30 s (β = - 0.49, p < 0.001), chair-stands in 30 s (β = - 0.43, p < 0.001), sit-ups in 30 s (β = - 0.52, p < 0.001), the sit-and reach test (β = - 0.40, p < 0.001) and the 2-min step test (β = - 0.35, p < 0.001). This study shows that fasting blood glucose may be predicted by health-related physical fitness test in war veterans.

The impact of concurrent training and antioxidant supplementation on the factors associated with the ocular lens opacity in diabetic rats

The current study was aimed to investigate the protective effect of vitamins C and E (VCE) supplementation, exercise, and their concurrent application against cataract incidence in the diabetic rats. The obtained results indicated that different supplementation and training treatments were capable to preserve the lens transparency in the diabetic rats. Also, upon applying different supplementation and training treatments, the level of glutathione (GSH) and activity of antioxidant enzymes in the diabetic rats was preserved approximately close to their control levels. In addition, different treatments were capable to maintain the structural integrity of the lens proteins in diabetic rats. Moreover, VCE supplementation, exercise and their simultaneous application prevented lens crystallins of diabetic rats against fibrillation and formation of the increased oligomeric sizes. The results of this study signify the importance of antioxidant supplementation and exercise in reducing the detrimental effects of hyperglycemia on the eye lenses.

A single bout of cycling exercise induces nucleosome repositioning in the skeletal muscle of lean and overweight/obese individuals

AIM

To compare the molecular and metabolic effects of a single exercise bout in the skeletal muscle between lean and overweight/obese (Ov/Ob) individuals.

MATERIALS AND METHODS

Participants recruited were men, aged 19-30 years, who were either lean (body mass index [BMI] < 25, 18.5-24.1 kg/m² ; n = 15) or Ov/Ob (BMI ≥ 25, 25.5-36.9 kg/m² ; n = 15). Four hours after a high-carbohydrate breakfast (7 kcal/kg; 60% carbohydrate, 25% fat, 15% protein), participants performed a cycling exercise (50% VO₂ max, expending ~650 kcal). Muscle biopsies and peripheral blood samples were collected 30 minutes before the meal and immediately after exercise. Blood analysis, and muscle acylcarnitine profiles, transcriptomics, and nucleosome mapping by micrococcal nuclease digestion with deep sequencing were performed.

RESULTS

A single exercise bout improved blood metabolite profiles in both lean and Ov/Ob individuals. Muscle long-chain acylcarnitines were increased in Ov/Ob compared with lean participants, but were not altered by exercise. A single exercise bout increased the mRNA abundance of genes related to mitochondria and insulin signalling in both lean and Ov/Ob participants. Nucleosome mapping by micrococcal nuclease digestion with deep sequencing revealed that exercise repositioned the -1 nucleosome away from the transcription start site of the PGC1a promoter and of other mitochondrial genes, but did not affect genes related to insulin signalling, in both lean and Ov/Ob participants.

CONCLUSION

These data suggest that a single exercise bout induced epigenetic alterations in skeletal muscle in a BMI-independent manner.

Prestroke physical activity and outcomes after intracerebral haemorrhage in comparison to ischaemic stroke: protocol for a matched cohort study (part of PAPSIGOT)

INTRODUCTION

Piling evidence suggests that a higher level of prestroke physical activity can decrease stroke severity, and reduce the risk of poststroke mortality. However, prior studies have only included ischaemic stroke cases, or a majority of such. We aim to investigate how premorbid physical activity influences admission stroke severity and poststroke mortality in patients with intracerebral haemorrhage, compared with ischaemic stroke. A prespecified analysis plan counteract some inherent biases in observational studies, and promotes transparency.

METHODS AND ANALYSIS

This is a statistical analysis protocol for a matched cohort study, including all adult patients with intracerebral haemorrhage, and matched ischaemic stroke controls, treated at Sahlgrenska University Hospital in Sweden between 1 November 2014 and 30 June 2019. All patients have been identified in the Väststroke register, and the data file has been sent for merging with national registries. The follow-up of time for survival will be approximately 2-7 years. The sample size calculation indicates that a minimum of 628 patients with intracerebral haemorrhage is needed for power of 80% at an alpha level of 0.01. Multiple imputation by chained equations will be used to handle missing data. The entire cohort of patients with intracerebral haemorrhage will be matched with consecutive ischaemic stroke controls (1:3 ratio) using nearest neighbour propensity score matching. The association between prestroke physical activity and admission stroke severity will be evaluated using multivariable ordinal regression models, and risk for all-cause mortality will be analysed using multivariable Cox proportional-hazards models. Potential confounders include age, ethnicity, income, educational level, comorbidity, medical treatments, alcohol-related disorders, drug abuse and smoking.

ETHICS

Data collection for the Physical Activity Pre-Stroke In GOThenburg project was approved by the Regional Ethical Board on 4 May 2016. An additional application was approved by the National Ethical Review Authority on 7 July 2021.

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.

An Education-Support-Group Program for Visually Impaired People with Diabetes

This article describes the Diabetes Education/Support Group Program for people with diabetes and visual impairment. It analyzes some of the common problems that participants have reported, and discusses some methods of reducing anxiety and depression related to the two conditions.

Physical Activity Pattern and Its Association with Glycaemic and Blood Pressure Control among People Living with Diabetes (PLWD) In The Ho Municipality, Ghana

Background

Physical activity (PA) offers considerable health benefits for diabetic patients. However, extensive high levels of inactivity has been reported among diabetic patients. This study sought to assess the patterns of physical activity and its relationship with two management-relevant outcomes (glycaemic and blood pressure control)among people living with diabetes in the Ho Municipality, Ghana.

Methods

A hospital-based cross-sectional study was carried out from January 2017 to April 2017 among 150 purposively recruited diabetic patients who were receiving care at the diabetes clinics of the Volta Regional Hospital and the Ho Municipal Hospital. A semi-structured questionnaire was used in capturing socio-demographic information. Physical activity was assessed using the International Physical Activity Questionnaire Short Form. Glycaemic and blood pressure control were evaluated within a three-month period from patients' records.

Results

Physical activity estimates among participants were 21.33%, 48% and 30.67% for high, moderate and low PA respectively. Glycaemic control among the study participants was 33.33% and blood pressure control was 58.67%. Both glycaemic and blood pressure control were significantly associated with PA.

Conclusion

In this group of PLWD in the Ho Municipality, high levels of inactivity, uncontrolled glycaemia and blood pressure exist. However, glycaemic and blood pressure control may be modulated by moderate-intensity physical activity.

Cardiovascular Effects and Benefits of Exercise

It is widely accepted that regular physical activity is beneficial for cardiovascular health. Frequent exercise is robustly associated with a decrease in cardiovascular mortality as well as the risk of developing cardiovascular disease. Physically active individuals have lower blood pressure, higher insulin sensitivity, and a more favorable plasma lipoprotein profile. Animal models of exercise show that repeated physical activity suppresses atherogenesis and increases the availability of vasodilatory mediators such as nitric oxide. Exercise has also been found to have beneficial effects on the heart. Acutely, exercise increases cardiac output and blood pressure, but individuals adapted to exercise show lower resting heart rate and cardiac hypertrophy. Both cardiac and vascular changes have been linked to a variety of changes in tissue metabolism and signaling, although our understanding of the contribution of the underlying mechanisms remains incomplete. Even though moderate levels of exercise have been found to be consistently associated with a reduction in cardiovascular disease risk, there is evidence to suggest that continuously high levels of exercise (e.g., marathon running) could have detrimental effects on cardiovascular health. Nevertheless, a specific dose response relationship between the extent and duration of exercise and the reduction in cardiovascular disease risk and mortality remains unclear. Further studies are needed to identify the mechanisms that impart cardiovascular benefits of exercise in order to develop more effective exercise regimens, test the interaction of exercise with diet, and develop pharmacological interventions for those unwilling or unable to exercise.

Exercise to preserve β-cell function in recent-onset Type 1 diabetes mellitus (EXTOD) - a randomized controlled pilot trial

AIM

Residual β-cell function is present at the time of diagnosis with Type 1 diabetes. Preserving this β-cell function reduces complications. We hypothesized that exercise preserves β-cell function in Type 1 diabetes and undertook a pilot trial to address the key uncertainties in designing a definitive trial to test this hypothesis.

METHODS

A randomized controlled pilot trial in adults aged 16-60 years diagnosed with Type 1 diabetes within the previous 3 months was undertaken. Participants were assigned to control (usual care) or intervention (exercise consultation every month), in a 1 : 1 ratio for 12 months. The primary outcomes were recruitment rate, drop out, exercise adherence [weeks with ≥ 150 min of self-reported moderate to vigorous physical activity (MVPA)], and exercise uptake in the control group. The secondary outcomes were differences in insulin sensitivity and rate of loss of β-cell function between intervention and control at 6 and 12 months.

RESULTS

Of 507 individuals who were approached, 58 (28 control, 30 intervention) entered the study and 41 completed it. Participants were largely white European males, BMI 24.8 ± 3.8 kg/m² , HbA_1c 75 ± 25 mmol/mol (9 ± 2%). Mean level of objectively measured MVPA increased in the intervention group (mean 243 to 273 min/week) and 61% of intervention participants reached the target of ≥ 150 min/week of self-reported MVPA on at least 42 weeks of the year. Physical activity levels fell slightly in the control group (mean 277 to 235 min of MVPA/week). There was exploratory evidence that intervention group became more insulin sensitive and required less insulin. However, the rate of loss of β-cell function appeared similar between the groups, although the change in insulin sensitivity may have affected this.

CONCLUSION

We show that it is possible to recruit and randomize people with newly diagnosed Type 1 diabetes to a trial of an exercise intervention, and increase and maintain their exercise levels for 12 months. Future trials need to incorporate measures of greater adherence to exercise training targets, and include more appropriate measures of β-cell function. (Clinical Trials Registry No; ISRCTN91388505).

State of the Art Reviews: Relationship Between Diet/ Physical Activity and Health

Obesity and 4 of the leading causes of death—heart disease, cancer, stroke, and type 2 diabetes mellitus—are related to lifestyle. The combination of a healthy weight, prudent diet, and daily physical activity clearly plays a role in primary, secondary, and tertiary prevention of these and other chronic diseases. Because nearly 65% of the adult population is overweight or obese, weight loss and maintenance are central to this review article. Improved lipid profiles, blood pressure, insulin sensitivity, and euglycemia are associated with weight loss or a normal body weight; thus, maintaining a healthy weight is a universal recommendation for health. The methods for improving lifestyle described in the section on obesity include assessing nutritional status and stages of change of the client, setting realistic goals, eating a diet high in fruits and vegetables with low-fat sources of dairy and protein, and achieving appropriate physical activity levels. The importance of physicians discussing weight with clients and vice versa is stressed. The common features of lifestyle-related diseases make them amenable to similar lifestyle interventions.

Exercise as medicine - evidence for prescribing exercise as therapy in 26 different chronic diseases

This review provides the reader with the up-to-date evidence-based basis for prescribing exercise as medicine in the treatment of 26 different diseases: psychiatric diseases (depression, anxiety, stress, schizophrenia); neurological diseases (dementia, Parkinson's disease, multiple sclerosis); metabolic diseases (obesity, hyperlipidemia, metabolic syndrome, polycystic ovarian syndrome, type 2 diabetes, type 1 diabetes); cardiovascular diseases (hypertension, coronary heart disease, heart failure, cerebral apoplexy, and claudication intermittent); pulmonary diseases (chronic obstructive pulmonary disease, asthma, cystic fibrosis); musculo-skeletal disorders (osteoarthritis, osteoporosis, back pain, rheumatoid arthritis); and cancer. The effect of exercise therapy on disease pathogenesis and symptoms are given and the possible mechanisms of action are discussed. We have interpreted the scientific literature and for each disease, we provide the reader with our best advice regarding the optimal type and dose for prescription of exercise.

Exercise and diabetes: relevance and causes for response variability

Exercise as a key prevention strategy for diabetes and obesity is commonly accepted and recommended throughout the world. Unfortunately, not all individuals profit to the same extent, some exhibit exercise resistance. This phenomenon of non-response to exercise is found for several endpoints, including glucose tolerance and insulin sensitivity. Since these non-responders are of notable quantity, there is the need to understand the underlying mechanisms and to identify predictors of response. This displays the basis to develop personalized training intervention regimes. In this review, we summarize the current knowledge on response variability, with focus on human studies and improvement of glucose homeostasis as outcome.

High Intensity Interval Training Improves Glycaemic Control and Pancreatic β Cell Function of Type 2 Diabetes Patients

Physical activity improves the regulation of glucose homeostasis in both type 2 diabetes (T2D) patients and healthy individuals, but the effect on pancreatic β cell function is unknown. We investigated glycaemic control, pancreatic function and total fat mass before and after 8 weeks of low volume high intensity interval training (HIIT) on cycle ergometer in T2D patients and matched healthy control individuals. Study design/method: Elderly (56 yrs±2), non-active T2D patients (n = 10) and matched (52 yrs±2) healthy controls (CON) (n = 13) exercised 3 times (10×60 sec. HIIT) a week over an 8 week period on a cycle ergometer. Participants underwent a 2-hour oral glucose tolerance test (OGTT). On a separate day, resting blood pressure measurement was conducted followed by an incremental maximal oxygen uptake (V˙O_2max) cycle ergometer test. Finally, a whole body dual X-ray absorptiometry (DXA) was performed. After 8 weeks of training, the same measurements were performed. Results: in the T2D-group, glycaemic control as determined by average fasting venous glucose concentration (p = 0.01), end point 2-hour OGTT (p = 0.04) and glycosylated haemoglobin (p = 0.04) were significantly reduced. Pancreatic homeostasis as determined by homeostatic model assessment of insulin resistance (HOMA-IR) and HOMA β cell function (HOMA-%β) were both significantly ameliorated (p = 0.03 and p = 0.03, respectively). Whole body insulin sensitivity as determined by the disposition index (DI) was significantly increased (p = 0.03). During OGTT, the glucose continuum was significantly reduced at -15 (p = 0.03), 30 (p = 0.03) and 120 min (p = 0.03) and at -10 (p = 0.003) and 0 min (p = 0.003) with an additional improvement (p = 0.03) of its 1^st phase (30 min) area under curve (AUC). Significant abdominal fat mass losses were seen in both groups (T2D: p = 0.004 and CON: p = 0.02) corresponding to a percentage change of -17.84%±5.02 and -9.66%±3.07, respectively. Conclusion: these results demonstrate that HIIT improves overall glycaemic control and pancreatic β cell function in T2D patients. Additionally, both groups experienced abdominal fat mass losses. These findings demonstrate that HIIT is a health beneficial exercise strategy in T2D patients.

Pharmacological induction of mitochondrial biogenesis as a therapeutic strategy for the treatment of type 2 diabetes

Defects in mitochondrial oxidative function have been associated with the onset of type 2 diabetes. Although the causal relationship between mitochondrial dysfunction and diabetes has not been fully established, numerous studies indicate that improved glucose homeostasis achieved via lifestyle interventions, such as exercise or calorie restriction, is tightly associated with increased mitochondrial biogenesis and oxidative function. Therefore, it is conceivable that potentiating mitochondrial biogenesis by pharmacological means could constitute an efficacious therapeutic strategy that would particularly benefit those diabetic patients who cannot adhere to comprehensive programs based on changes in lifestyle or that require a relatively rapid improvement in their diabetic status. In this review, we discuss several pharmacological targets and drugs that modulate mitochondrial biogenesis as well as their potential use as treatments for insulin resistance and diabetes.

The time has come to test the beta cell preserving effects of exercise in patients with new onset type 1 diabetes

Type 1 diabetes is characterised by immune-mediated destruction of insulin-producing beta cells. Significant beta cell function is usually present at the time of diagnosis with type 1 diabetes, and preservation of this function has important clinical benefits. The last 30 years have seen a number of largely unsuccessful trials for beta cell preservation, some of which have been of therapies that have potential for significant harm. There is a need to explore new, more tolerable approaches to preserving beta cell function that can be implemented on a large clinical scale. Here we review the evidence for physical exercise as a therapy for the preservation of beta cell function in patients with newly diagnosed type 1 diabetes. We highlight possible mechanisms by which exercise could preserve beta cell function and then present evidence from other models of diabetes that demonstrate that exercise preserves beta cell function. We conclude by proposing that there is now a need for studies to explore whether exercise can preserve beta cell in patients newly diagnosed with type 1 diabetes.

Effects of changes in obesity and exercise on the development of diabetes and return to normal fasting plasma glucose levels at one-year follow-up in middle-aged subjects with impaired fasting glucose

OBJECTIVES

Borderline diabetes, a precursory condition of diabetes, is an important issue in the prevention of diabetes. The aim of the present study was to clarify the effects of one-year changes in obesity and exercise on the development of diabetes or return to normal fasting plasma glucose (FPG) levels among middle-aged people with impaired fasting glucose (IFG) at baseline.

METHODS

Among those who attended a basic health examination in 1997, we selected 1,620 subjects who showed impaired fasting glucose (FPG of 110 mg/dl or higher) and had complete data on height, weight and exercise. At the one-year follow-up (in 1998), 1,099 of those subjects attended a health examination; FPG, height, weight and exercise were evaluated for 731 subjects. Subjects were classified into the following three groups, on the basis of changes in FPG during the year between the two examinations: developing diabetes (DM), remaining IFG, and returning to normal (WNL).

RESULTS

Among those who were initially obese, there was a significant difference in the proportions of DM, IFG and WNL between those with and without improvement in obesity in the year preceding the follow-up (p<0.05). Those with improvement in obesity showed a significantly higher tendency to return to WNL than those without improvement in obesity. Multiple logistic regression analysis showed that those with improvement in obesity had a significantly higher odds ratio (2.17) to return to WNL (p=0.015). Among those who were initially not obese, there was no significant association between changes in obesity and developing DM or returning to WNL. No significant association was observed between changes in exercise and developing DM or returning to WNL.

CONCLUSION

The present findings suggest that, among obese IFG subjects, improvement in obesity is associated with returning to normal plasma glucose. Weight control may be important for the normalization of borderline diabetes.

Exercise training improves fasting glucose control

Purpose

Numerous studies have measured changes in fasting blood glucose (FBG) levels in response to physical activity (PA) interventions. While studies involving clinical populations such as type 2 diabetics typically report significant reductions, most others report no change in FBG. This study investigated changes in FBG in apparently healthy adults following a PA intervention.

Methods

We measured fingertip samples for FBG pre and post a 40-day PA program in 575 insufficiently active adults. The PA goal was at least 30 minutes of moderate exercise daily, and there was 73% compliance.

Results

A PA questionnaire showed the average level of activity was 69 ± 46 min/wk preintervention, and this increased to 635 ± 458 min/wk postintervention. When the change in FBG was regressed against baseline FBG levels, there was a significant negative relationship (y = 2.623 − 0.471 × x; r = 0.472; P < 0.0001). The regression line showed, on average, subjects with low pre-study glucose levels had increased FBG while those with high levels had reductions in FBG.

Conclusion

It appears that the body’s response to PA training is to upregulate glucose control, which is reflected in tighter FBG levels around a physiological set point (5.6 mmol/L, in the present study). Regulation of blood glucose is a complex neuroendocrine process with numerous organs involved, but it was not possible in the present study to determine which of these regulatory steps are involved in exercise-induced changes of FBG.

Aerobic and resistance training effects compared to aerobic training alone in obese type 2 diabetic patients on diet treatment

AIMS

The study was designed to compare a combined aerobic and resistance training (ART) with an aerobic training (AT) over hemodynamic, glucose metabolism and endothelial factors, adipokines and pro-inflammatory marker release in a population of obese type 2 diabetic patients.

METHODS

Forty-seven patients were randomly assigned to aerobic (27 patients) or aerobic plus resistance (20 patients) exercise trainings, on the top of a diet regime. Anthropometric, metabolic, hormonal and inflammatory variables were measured at hospitalization and discharge.

RESULTS

Both exercise programs equally improved body weight and fructosamine levels however ART only partially decreased HOMA index compared with AT (ART: -25% vs AT: -54%, p<0.01). Mean blood pressure (AT: -3.6 mmHg vs ART: +0.6 mmHg, p<0.05) and endothelin-1 (ET-1) incremental areas during walking test (AT: -11% vs ART: +30%, p<0.001) decreased after AT while increased after ART. Adiponectin levels increased by 54% after AT while decreased by 13% after ART (p<0.0001) and matrix metalloproteinase-2 (MMP-2), tumor necrosis factor-alpha (TNF-alpha) and monocyte chemoattractan protein-1 (MCP-1) levels significantly decreased in AT while increased in ART group.

CONCLUSIONS

Compared with AT, ART similarly enhanced body weight loss but exerted less positive effects on insulin sensitivity and endothelial factors, adipokines and pro-inflammatory marker release.

The DASH diet and insulin sensitivity

Lifestyle modifications, including adoption of the Dietary Approaches to Stop Hypertension (DASH) dietary pattern, weight loss in individuals who are overweight or obese, and physical activity, are effective in the prevention and treatment of hypertension. A healthy lifestyle may also have beneficial effects on metabolic abnormalities, such as insulin resistance, that are associated with high blood pressure. This review examines the independent and combined effects of the DASH diet and weight loss plus exercise on blood pressure and insulin sensitivity, with a focus on recently published results from the ENCORE study. Our data suggest that the DASH eating plan alone lowers blood pressure in overweight individuals with higher than optimal blood pressure, but significant improvements in insulin sensitivity are observed only when the DASH diet is implemented as part of a more comprehensive lifestyle modification program that includes exercise and weight loss.

Exercise in aging: its important role in mortality, obesity and insulin resistance

The prevalence of overweight and obesity has increased dramatically over the last several decades. Obesity and physical inactivity increase the risk for cardiovascular disease, Type 2 diabetes mellitus, hypertension, dyslipidemia and certain cancers. Obesity and low levels of physical fitness are also associated with increased risk of all-cause and cardiovascular mortality. Central and total obesity, insulin resistance and inactivity increase with age. Exercise training and increased fitness promote positive changes in body composition and improve insulin sensitivity. This article will describe the effects of exercise training, both aerobic and resistive, on body composition and obesity as well as review studies investigating the effects of exercise training on glucose metabolism and insulin sensitivity in older adults. Adopting a physically active lifestyle should be emphasized in overweight and obese individuals with insulin resistance to reduce the risk for cardiovascular events in the aging population.

Effects of the dietary approaches to stop hypertension diet alone and in combination with exercise and caloric restriction on insulin sensitivity and lipids

This study examined the effects of the Dietary Approaches to Stop Hypertension (DASH) diet on insulin sensitivity and lipids. In a randomized control trial, 144 overweight (body mass index: 25 to 40) men (n=47) and women (n=97) with high blood pressure (130 to 159/85 to 99 mm Hg) were randomly assigned to one of the following groups: (1) DASH diet alone; (2) DASH diet with aerobic exercise and caloric restriction; or (3) usual diet controls (UC). Body composition, fitness, insulin sensitivity, and fasting lipids were measured before and after 4 months of treatment. Insulin sensitivity was estimated on the basis of glucose and insulin levels in the fasting state and after an oral glucose load. Participants in the DASH diet with aerobic exercise and caloric restriction condition lost weight (-8.7 kg [95% CI: -2.0 to -9.7 kg]) and exhibited a significant increase in aerobic capacity, whereas the DASH diet alone and UC participants maintained their weight (-0.3 kg [95% CI: -1.2 to 0.5 kg] and +0.9 kg [95% CI: 0.0 to 1.7 kg], respectively) and had no improvement in exercise capacity. DASH diet with aerobic exercise and caloric restriction demonstrated lower glucose levels after the oral glucose load, improved insulin sensitivity, and lower total cholesterol and triglycerides compared with both DASH diet alone and UC, as well as lower fasting glucose and low-density lipoprotein cholesterol compared with UC. DASH diet alone participants generally did not differ from UC in these measures. Combining the DASH diet with exercise and weight loss resulted in significant improvements in insulin sensitivity and lipids. Despite clinically significant reductions in blood pressure, the DASH diet alone, without caloric restriction or exercise, resulted in minimal improvements in insulin sensitivity or lipids.

Preventing and managing cardiometabolic risk: the logic for intervention

Cardiometabolic risk (CMR), also known as metabolic syndrome or insulin resistance syndrome, comprises obesity (particularly central or abdominal obesity), high triglycerides, low HDL, elevated blood pressure, and elevated plasma glucose. Leading to death from diabetes, heart disease, and stroke, the root cause of CMR is inadequate physical activity, a Western diet identified primarily by low intake of fruits, vegetables, and whole grains, and high in saturated fat, as well as a number of yet-to-be-identified genetic factors. While the pathophysiological pathways related to CMR are complex, the universal need for adequate physical activity and a diet that emphasizes fruits and vegetables and whole grains, while minimizing food high in added sugars and saturated fat suggests that these behaviors are the appropriate focus of intervention.

Altered expression and insulin-induced trafficking of Na+-K+-ATPase in rat skeletal muscle: effects of high-fat diet and exercise

Skeletal muscle Na(+)-K(+)-ATPase plays a central role in the clearance of K(+) from the extracellular fluid, therefore maintaining blood [K(+)]. Na(+)-K(+)-ATPase activity in peripheral tissue is impaired in insulin resistant states. We determined effects of high-fat diet (HFD) and exercise training (ET) on skeletal muscle Na(+)-K(+)-ATPase subunit expression and insulin-stimulated translocation. Skeletal muscle expression of Na(+)-K(+)-ATPase isoforms and transcription factor DNA binding was determined before or after 5 days of swim training in Wistar rats fed chow or HFD for 4 or 12 wk. Skeletal muscle insulin resistance was observed after 12 wk of HFD. Na(+)-K(+)-ATPase alpha(1)-subunit protein expression was increased 1.6-fold (P < 0.05), whereas alpha(2)- and beta(1)-subunits and protein expression were decreased twofold (P < 0.01) in parallel with decrease in plasma membrane Na(+)-K(+)-ATPase activity after 4 wk of HFD. Exercise training restored alpha(1)-, alpha(2)-, and beta(1)-subunit expression and Na(+)-K(+)-ATPase activity to control levels and reduced beta(2)-subunit expression 2.2-fold (P < 0.05). DNA binding activity of the alpha(1)-subunit-regulating transcription factor ZEB (AREB6) and alpha(1) mRNA expression were increased after HFD and restored by ET. DNA binding activity of Sp-1, a transcription factor involved in the regulation of alpha(2)- and beta(1)-subunit expression, was decreased after HFD. ET increased phosphorylation of the Na(+)-K(+)-ATPase regulatory protein phospholemman. Phospholemman mRNA and protein expression were increased after HFD and restored to control levels after ET. Insulin-stimulated translocation of the alpha(2)-subunit to plasma membrane was impaired by HFD, whereas alpha(1)-subunit translocation remained unchanged. Alterations in sodium pump function precede the development of skeletal muscle insulin resistance. Disturbances in skeletal muscle Na(+)-K(+)-ATPase regulation, particularly the alpha(2)-subunit, may contribute to impaired ion homeostasis in insulin-resistant states such as obesity and type 2 diabetes.

Cardiovascular and metabolic complications during androgen deprivation: exercise as a potential countermeasure

Apart from the well-established adverse musculoskeletal and sexual health effects of androgen deprivation therapy (ADT), evidence is accumulating of substantial ADT-related cardiovascular and metabolic complications, which may impact quality of life and overall survival. In this brief review we discuss (1) the incidence of cardiovascular and metabolic complications during/following ADT from large cohort studies, (2) the increased risk factors for cardiovascular and metabolic disease from cross-sectional and prospective studies and (3) the use of physical exercise as a countermeasure in this new era of ADT-related toxicity. It is clear that exercise has the potential to provide a myriad of benefits to men undergoing ADT that may result in reduced morbidity and mortality, and subsequently improve quality of life.

Lipoprotein profile, glycemic control and physical fitness after strength and aerobic training in post-menopausal women with type 2 diabetes

We studied the effects on blood lipids and physical fitness after a training program that combined strength and aerobic exercise in postmenopausal women with type 2 diabetes. Ten patients (55.0 +/- 5.2 years) followed four exercise sessions per week, two strength and two aerobic, and ten (59.4 +/- 3.2 years) served as a control group. Lipid profile, glycated hemoglobin (HbA(1c)), HOMA2 index, exercise stress and muscular testing were assessed at the beginning and after 16 weeks of training program. Exercise training increased significantly HDL-C (17.2%; P < 0.001) and decreased triglycerides (18.9%), HbA(1c) (15.0%), fasting plasma glucose (5.4%), insulin resistance (HOMA2 25.2%) and resting blood pressure (P < 0.01). After 16 weeks of training, exercise time (17.8%) and muscular strength increased significantly (P < 0.001). The results indicated that a combined strength and aerobic training program could induce positive adaptations on lipid profile, glycemic control, insulin resistance, cardiovascular function, and physical fitness in post-menopausal women with type 2 diabetes.

A controlled randomized study on the effect of long-term physical exercise on the metabolic control in type 2 diabetic patients

The effects of 4 months' physical exercise on the metabolic control in non-insulin-dependent diabetes were studied in 25 patients divided randomly into exercise (n = 13) and control (n = 12) groups. In the exercise group glycosylated hemoglobin A1 fell from 9.6-8.6% (p less than 0.01) and the 2 hour plasma glucose in oral glucose tolerance test decreased from 19.7-16.5 mmol/l (p less than 0.01). The mean fall in fasting plasma glucose from 11.8-10.5 mmol/l was not statistically significant. The responses of plasma insulin and C-peptide to oral glucose increased significantly during the exercise period. However, patients with initially poorest metabolic control were not able to improve their physical fitness and did not show significant improvement in metabolic control. In the control group no changes occurred in any parameter of glucose metabolism. The results suggest that physical exercise is beneficial for the glycemic control in patients with mild and moderate non-insulin-dependent diabetes. Increased insulin response is at least one main mechanism of the action of exercise.

Effects of exercise on glucose tolerance and insulin resistance. Brief review and some preliminary results

With aging, glucose tolerance (GT) declines, plasma insulin concentration increases, and sensitivity to the action of insulin declines. Evidence is accumulating that this decline in glucose tolerance and insulin sensitivity can be prevented by regularly performed vigorous exercise. Preliminary results are presented in this paper showing that prolonged, strenuous and frequent exercise can also completely normalize GT by decreasing resistance to insulin in some patients with mild non insulin dependent diabetes mellitus (NIDDM) and in some individuals with impaired glucose tolerance (IGT). Exercise appears to be effective in normalizing GT only in patients who still have an adequate capacity to secrete insulin, and in whom insulin resistance is the major cause for abnormal GT. The amount of exercise required to normalize GT in such patients appears to be in the range of 25 to 35 km per week of running, or a comparable amount of another form of exercise, performed on a regular basis.

Aerobic physical activity and resistance training: an application of the theory of planned behavior among adults with type 2 diabetes in a random, national sample of Canadians

Background

Aerobic physical activity (PA) and resistance training are paramount in the treatment and management of type 2 diabetes (T2D), but few studies have examined the determinants of both types of exercise in the same sample.

Objective

The primary purpose was to investigate the utility of the Theory of Planned Behavior (TPB) in explaining aerobic PA and resistance training in a population sample of T2D adults.

Methods

A total of 244 individuals were recruited through a random national sample which was created by generating a random list of household phone numbers. The list was proportionate to the actual number of household telephone numbers for each Canadian province (with the exception of Quebec). These individuals completed self-report TPB constructs of attitude, subjective norm, perceived behavioral control and intention, and a 3-month follow-up that assessed aerobic PA and resistance training.

Results

TPB explained 10% and 8% of the variance respectively for aerobic PA and resistance training; and accounted for 39% and 45% of the variance respectively for aerobic PA and resistance training intentions.

Conclusion

These results may guide the development of appropriate PA interventions for aerobic PA and resistance training based on the TPB.

[Treatment of type 2 diabetes: revision of current therapeutical options and priorities]

The paradigm of type 2 diabetes mellitus treatment is based in an adequate meal plan and the regular practice of physical exercise. The benefits of these measures are of evident as it is the perseverance in their compliance. In the daily practice, this reality favours the early implementation of a pharmacological therapy that, in the opinion of different experts, would be simultaneous to the introduction of life style changes. In the last years, new drugs have been developed. On the one hand, there are agents with beneficial effects not only on blood glucose control but also on the components of metabolic syndrome. Other drugs, according to different experts, have doubtful therapeutical contribution. The appearance of new drugs to treat obesity, associated with diabetes or not, extends other possibilities of choice to take into account. The great variety of options makes the decision of the adequate therapy more difficult. In the last decade, many therapeutic guidelines have been developed, with convergences and divergences that may mislead the inexpert practitioners. In this review we propose some practical advise in diet and exercise, and an evaluation of the different drugs and rules of intervention proposed in the different therapeutic guidelines. The ultimate goal is to facilitate and direct type 2 diabetes management.

State of the Art Reviews: Relationship Between Diet/ Physical Activity and Health

Obesity and 4 of the leading causes of death—heart disease, cancer, stroke, and type 2 diabetes mellitus—are related to lifestyle. The combination of a healthy weight, prudent diet, and daily physical activity clearly plays a role in primary, secondary, and tertiary prevention of these and other chronic diseases. Because nearly 65% of the adult population is overweight or obese, weight loss and maintenance are central to this review article. Improved lipid profiles, blood pressure, insulin sensitivity, and euglycemia are associated with weight loss or a normal body weight; thus, maintaining a healthy weight is a universal recommendation for health. The methods for improving lifestyle described in the section on obesity include assessing nutritional status and stages of change of the client, setting realistic goals, eating a diet high in fruits and vegetables with low-fat sources of dairy and protein, and achieving appropriate physical activity levels. The importance of physicians discussing weight with clients and vice versa is stressed. The common features of lifestyle-related diseases make them amenable to similar lifestyle interventions.

Acute effect of exercise on plasma leptin level and insulin resistance in obese women with stable caloric intake

Obese individuals are frequently hyperleptinemic and insulin resistant. Chronic exercise is associated with improvements in plasma leptin level and insulin sensitivity; however, little is known about the acute effect of exercise on these parameters. The aim of this study was to evaluate the acute effect of aerobic exercise on plasma leptin and insulin sensitivity in obese women with stable caloric intake.

PATIENTS AND METHODS

Twenty-three obese women (age 41.2 +/- 10.3 years, body mass index 40.7 +/- 6.7 kg/m2) were included to the study. All subjects were admitted to an exercise program (45-minute walking sessions at 60-80% of maximum heart rate) every day except weekends for four weeks (total 20 exercise sessions). Insulin resistance was evaluated by HOMA model. Plasma glucose, insulin and leptin levels were determined at baseline and at the end of the first, seventh, and twentieth exercise session.

RESULTS

Baseline and at the end of the first, seventh, and twentieth exercise session plasma leptin levels were 59.1 +/- 20.1, 58.5 +/- 21.0, 53.4 +/- 21.9, and 51.2 +/- 20.5 ng/ml and HOMA-r were 2.75 +/- 1.47, 1.77 +/- 0.71, 1.73 +/- 0.89, 1.62 +/- 0. 70, respectively. Compared to baseline, at the end of the seventh (p = 0.021) and twentieth exercise session (p = 0.003), plasma leptin levels were significantly low. Plasma leptin level did not change significantly at the end of the first exercise session (p > 0.05). At the end of the first exercise session (p = 0.005), end of the seventh (p = 0.003) and twentieth exercise session (p = 0.007) HOMA-r was lower than baseline. There was no correlation between weight loss during exercise period and the change of leptin, and HOMA-r. Fasting plasma glucose, insulin and leptin levels were determined at baseline and at the end of the first, seventh, and twentieth exercise session.

CONCLUSION

Our study suggests that acute exercise decreases insulin resistance at the first exercise session with no effect on leptin levels. Significant leptin decrement was evident at the first week and lasted during the entire four weeks exercise session.

Effects of different modes of exercise training on glucose control and risk factors for complications in type 2 diabetic patients: a meta-analysis

OBJECTIVE

We sought to meta-analyze the effects of different modes of exercise training on measures of glucose control and other risk factors for complications of diabetes.

RESEARCH DESIGN AND METHODS

The 27 qualifying studies were controlled trials providing, for each measure, 4-18 estimates for the effect of aerobic training, 2-7 for resistance training, and 1-5 for combined training, with 1,003 type 2 diabetic patients (age 55 +/- 7 years [mean +/- between-study SD]) over 5-104 weeks. The meta-analytic mixed model included main-effect covariates to control for between-study differences in disease severity, sex, total training time, training intensity, and dietary cointervention (13 studies). To interpret magnitudes, effects were standardized after meta-analysis using composite baseline between-subject SD.

RESULTS

Differences among the effects of aerobic, resistance, and combined training on HbA(1c) (A1C) were trivial; for training lasting >/=12 weeks, the overall effect was a small beneficial reduction (A1C 0.8 +/- 0.3% [mean +/- 90% confidence limit]). There were generally small to moderate benefits for other measures of glucose control. For other risk factors, there were either small benefits or effects were trivial or unclear, although combined training was generally superior to aerobic and resistance training. Effects of covariates were generally trivial or unclear, but there were small additional benefits of exercise on glucose control with increased disease severity.

CONCLUSIONS

All forms of exercise training produce small benefits in the main measure of glucose control: A1C. The effects are similar to those of dietary, drug, and insulin treatments. The clinical importance of combining these treatments needs further research.

Meta-analysis of the effect of exercise interventions on fitness outcomes among adults with type 1 and type 2 diabetes

This review applied meta-analytic procedures to integrate primary research that examined exercise fitness outcomes among adults with type 1 or type 2 diabetes. We used extensive literature searching strategies to locate published and unpublished intervention studies that tested exercise interventions. We conducted meta-analytic procedures using both fixed- and random-effects models. Analyses were conducted separately for type 1 and type 2 diabetes and separately for two-group and single-group data under two assumptions about pre-post fitness outcomes association: no association and a strong positive association (0.80). Codable data were extracted from 35 reports with 1074 subjects. The type 1 diabetes overall weighted mean effect size for two-group comparisons was 0.65. For treatment group pretest versus post-test, the effect was 0.62. The effect size among adults with type 2 diabetes for two-group comparisons was 0.35. The treatment group pretest versus post-test comparison effect was 0.37. Effect sizes among control group participants were not statistically different from 0. For type 2 diabetes two-group comparisons, larger effect sizes were associated with exercise prescription, fitness testing, supervised exercise, group sessions, and recommendations for longer duration exercise sessions. HbA1c, age, body mass index, and gender distribution were unrelated to fitness outcomes.

Evidence for prescribing exercise as therapy in chronic disease

Considerable knowledge has accumulated in recent decades concerning the significance of physical activity in the treatment of a number of diseases, including diseases that do not primarily manifest as disorders of the locomotive apparatus. In this review we present the evidence for prescribing exercise therapy in the treatment of metabolic syndrome-related disorders (insulin resistance, type 2 diabetes, dyslipidemia, hypertension, obesity), heart and pulmonary diseases (chronic obstructive pulmonary disease, coronary heart disease, chronic heart failure, intermittent claudication), muscle, bone and joint diseases (osteoarthritis, rheumatoid arthritis, osteoporosis, fibromyalgia, chronic fatigue syndrome) and cancer, depression, asthma and type 1 diabetes. For each disease, we review the effect of exercise therapy on disease pathogenesis, on symptoms specific to the diagnosis, on physical fitness or strength and on quality of life. The possible mechanisms of action are briefly examined and the principles for prescribing exercise therapy are discussed, focusing on the type and amount of exercise and possible contraindications.

Energy well spent fighting the diabetes epidemic

As the global burden of type 2 diabetes increases, medical science races to comprehensively understand its molecular aetiology. We suggest that the apparent struggle to seek a pharmacological or molecular victory to the diabetes epidemic is a flawed strategy given that evolution has already provided us with the best medicine. Recent molecular evidence highlights the interaction between muscle fatty acid kinetics in dictating whole body insulin action. Insights from an evolutionary perspective suggest that the ability of the body to evoke insulin resistance and store energy as fat within muscle cells is a normal physiological response to aid our survival during food or carbohydrate scarcity, but this 'hunter-gatherer physiology' predisposes to diabetes in a modern environment characterized by ample food availability and muscle inactivity. We contend that the true value of physical activity in the prevention and treatment of insulin resistance has been missed by the medical community because scientific investigation has been constructed upon physical activity recommendations that were never intended for this purpose. These recommendations provide a level of metabolic stress insufficient to be compatible with the expectations of our genes.

Effects of exercise training on glucose homeostasis: the HERITAGE Family Study

OBJECTIVE

To determine the effect of a 20-week endurance training program in healthy, previously sedentary participants on measures derived from an intravenous glucose tolerance test (i.v.GTT).

RESEARCH DESIGN AND METHODS

An i.v.GTT was performed before and after a standardized training program in 316 women and 280 men (173 blacks and 423 whites). Participants exercised on cycle ergometers 3 days per week for 60 sessions. The exercise intensity was progressively increased from 55% VO2max for 30 min per session to 75% VO2max for 50 min per session.

RESULTS

Mean insulin sensitivity increased by 10% (P < 0.001) following the intervention, but the variability in the changes was high. Men had larger improvements than women (P = 0.02). Improvements in fasting insulin were transitory, disappearing 72 h after the last bout of exercise. There were also significant mean increases in the glucose disappearance index (3%, P = 0.02) and in glucose effectiveness (11%, P < 0.001), measures of glucose tolerance and of the capacity of glucose to mediate its own disposal, respectively. The acute insulin response to glucose, a measure of insulin secretion, increased by 7% in the quartile with the lowest baseline glucose tolerance and decreased by 14% in the quartile with the highest baseline glucose tolerance (P < 0.001). The glucose area below fasting levels during the i.v.GTT was reduced by 7% (P = 0.02).

CONCLUSIONS

Although the effects of structured regular exercise were highly variable, there were improvements in virtually all i.v.GTT-derived variables. In the absence of substantial weight loss, regular exercise is required for sustained improvements in glucose homeostasis.

The effects of a combined strength and aerobic exercise program on glucose control and insulin action in women with type 2 diabetes

The purpose of the present study was to investigate the short- and long-term effects of a combined strength and aerobic training program on glycemic control, insulin action, exercise capacity and muscular strength in postmenopausal women with type 2 diabetes. Nine postmenopausal women, aged 55.2 (6.7) years, with type 2 diabetes participated in a supervised training program for 4 months consisting of two strength training sessions (3 sets of 12 repetitions at 60% one-repetition maximum strength) and two aerobic training sessions (60-70% of maximum heart rate at the beginning, and 70-80% of maximum heart rate after 2 months). Anthropometrical measurements, percentage glycated hemoglobin, a 2-h oral glucose tolerance test, exercise stress testing and maximum strength were measured at the beginning, and after 4 and 16 weeks of the exercise program. Significant reductions were observed in both the glucose (8.1% P<0.01) and insulin areas under the curve (20.7%, P<0.05) after 4 weeks of training. These adaptations were further improved after 16 weeks (glucose 12.5%, insulin 38%, P<0.001). Glycated hemoglobin was significantly decreased after 4 weeks [7.7 (1.7) vs 7.1 (1.3)%, P<0.05] and after 16 weeks [7.7 (1.7) vs 6.9 (1.0)%, P<0.01] of exercise training. Furthermore, exercise time and muscular strength were significantly improved after 4 weeks (P<0.01) as well as after 16 weeks (P<0.001) of training. Body mass and body-mass index, however, were not significantly altered throughout the study. The results indicated that a combined training program of strength and aerobic exercise could induce positive adaptations on glucose control, insulin action, muscular strength and exercise tolerance in women with type 2 diabetes.

Physical training may enhance beta-cell function in type 2 diabetes

In healthy young subjects, training increases insulin sensitivity but decreases the capacity to secrete insulin. We studied whether training changes beta-cell function in type 2 diabetic patients. Patients, stratified into "moderate" and "low" secretors according to individual C-peptide responses to an intravenous glucagon test, were randomly assigned to a training program [ergometer cycling 30-40 min/day, including at least 20 min at 75% maximum oxygen consumption (Vo(2 max)), 5 days/wk for 3 mo] or a sedentary schedule. Before and after the intervention (16 h after last training bout), a sequential hyperglycemic (90 min at 11, 18, and 25 mM) clamp was performed. An intravenous bolus of 5 g of arginine was given at the end. Training increased Vo(2 max) 17 +/- 13% and decreased heart rate during submaximal exercise (P < 0.05). During the 3 mo of sedentary lifestyle, insulin and C-peptide responses to the clamp procedures were unchanged in both moderate and low secretors. Likewise, no change in beta-cell response was seen after training in the low secretors (n = 5). In contrast, moderate secretors (n = 9) showed significant increases in beta-cell responses to 18 and 25 mM hyperglycemia and to arginine stimulation. Glucagon responses to arginine as well as measures of insulin sensitivity and Hb A(1c) levels were not altered by training. In conclusion, in type 2 diabetic patients, training may enhance beta-cell function if the remaining secretory capacity is moderate but not if it is low. The improved beta-cell function does not require changes in insulin sensitivity and Hb A(1c) concentration.

Cardiovascular prevention in type 2 diabetic patients: review of efficacious treatments

BACKGROUND

Type 2 diabetes (t2DM) is a chronic and complex metabolic condition requiring continuing medical care in order to reduce the risk of long-term complications. Macrovascular complications cause about 65% of deaths in subjects with t2DM and are responsible for severe co-morbidity. Many studies have addressed cardiovascular (CV) risk reduction in t2DM subjects.

OBJECTIVES

To summarise the evidence concerning the impact of lifestyle and of medical interventions in t2DM patients on CV risk (myocardial infarction, stroke, CV death, or a combination of these).

METHODS

We successively reviewed the recent guidelines addressing CV prevention in t2DM and searched the Cochrane Controlled Trials Register (CCTR), Medline & Embase to find systematic reviews and original articles on CV events in t2DM patients. We selected original studies which included solely t2DM patients or a large t2DM subgroup (n>100), tested lifestyle habits or drug treatments, and analysed CV endpoints. Their design had to be a randomised controlled trial for drug interventions, and a prospective cohort for lifestyle habits. MAIN STUDIES: We found 4 major guidelines focusing on CV prevention in t2DM patients, all released in 2003, and 10 reviews and meta-analyses: one dealing with dietary intervention, three with blood pressure lowering, one with ACE-inhibitors, one (with update) with platelet-inhibitors , three with cholesterol-inhibitors and one that dealt with both cholesterol-inhibition and blood pressure lowering. We included cohort studies on cigarette smoking (1), physical exercise (3) and weight control (1), as well as randomised trials on treatment of glycaemia (1), lipidaemia (13), blood pressure (12) and platelet aggregation (4). We also included one open randomised trial dealing with a multifactorial treatment.

CONCLUSIONS

Global CV risk management in t2DM should aim at changes in lifestyle habits and daily use of multiple drugs. Treatment should be long-term and target-driven with intensified interventions aimed at all validated targets. Lifestyle approach is of primary importance. Five targets are supported by strong clinical evidence (Table 4): reduction of blood pressure and of LDL-Cholesterol to normal values, and the use of three types of drugs which inhibit, respectively, platelet aggregation, angiotensin pathway and cholesterol synthesis.