Exercise is required for visceral fat loss in postmenopausal women with type 2 diabetes

Impact of baseline adipose tissue characteristics on change in adipose tissue volume during a low calorie diet in people with obesity-results from the LION study

BACKGROUND/OBJECTIVES

Weight loss outcomes vary individually. Magnetic resonance imaging (MRI)-based evaluation of adipose tissue (AT) might help to identify AT characteristics that predict AT loss. This study aimed to assess the impact of an 8-week low-calorie diet (LCD) on different AT depots and to identify predictors of short-term AT loss using MRI in adults with obesity.

METHODS

Eighty-one adults with obesity (mean BMI 34.08 ± 2.75 kg/m², mean age 46.3 ± 10.97 years, 49 females) prospectively underwent baseline MRI (liver dome to femoral head) and anthropometric measurements (BMI, waist-to-hip-ratio, body fat), followed by a post-LCD-examination. Visceral and subcutaneous AT (VAT and SAT) volumes and AT fat fraction were extracted from the MRI data. Apparent lipid volumes based on MRI were calculated as approximation for the lipid contained in the AT. SAT and VAT volumes were subdivided into equidistant thirds along the craniocaudal axis and normalized by length of the segmentation. T-tests compared baseline and follow-up measurements and sex differences. Effect sizes on subdivided AT volumes were compared. Spearman Rank correlation explored associations between baseline parameters and AT loss. Multiple regression analysis identified baseline predictors for AT loss.

RESULTS

Following the LCD, participants exhibited significant weight loss (11.61 ± 3.07 kg, p < 0.01) and reductions in all MRI-based AT parameters (p < 0.01). Absolute SAT loss exceeded VAT loss, while relative apparent lipid loss was higher in VAT (both p < 0.01). The lower abdominopelvic third showed the most significant SAT and VAT reduction. The predictor of most AT and apparent lipid losses was the normalized baseline SAT volume in the lower abdominopelvic third, with smaller volumes favoring greater AT loss (p < 0.01 for SAT and VAT loss and SAT apparent lipid volume loss).

CONCLUSIONS

The LCD primarily reduces lower abdominopelvic SAT and VAT. Furthermore, lower abdominopelvic SAT volume was detected as a potential predictor for short-term AT loss in persons with obesity.

Exercise induces tissue-specific adaptations to enhance cardiometabolic health

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

The predictive significance of lipid accumulation products for future diabetes in a non-diabetic population from a gender perspective: an analysis using time-dependent receiver operating characteristics

Objective

The increasing prevalence of diabetes is strongly associated with visceral adipose tissue (VAT), and gender differences in VAT remarkably affect the risk of developing diabetes. This study aimed to assess the predictive significance of lipid accumulation products (LAP) for the future onset of diabetes from a gender perspective.

Methods

A total of 8,430 male and 7,034 female non-diabetic participants in the NAGALA (NAfld in the Gifu Area, Longitudinal Analysis) program were included. The ability of LAP to assess the risk of future new-onset diabetes in both genders was analyzed using multivariate Cox regression. Subgroup analysis was conducted to explore the impact of potential modifiers on the association between LAP and diabetes. Additionally, time-dependent receiver operator characteristics (ROC) curves were used to assess the predictive power of LAP in both genders for new-onset diabetes over the next 2-12 years.

Results

Over an average follow-up of 6.13 years (maximum 13.14 years), 373 participants developed diabetes. Multivariate Cox regression analysis showed a significant gender difference in the association between LAP and future diabetes risk (P-interaction<0.05): the risk of diabetes associated with LAP was greater in females than males [hazard ratios (HRs) per standard deviation (SD) increase: male 1.20 (1.10, 1.30) vs female 1.35 (1.11, 1.64)]. Subgroup analysis revealed no significant modifying effect of factors such as age, body mass index (BMI), smoking history, drinking history, exercise habits, and fatty liver on the risk of diabetes associated with LAP (All P-interaction <0.05). Time-dependent ROC analysis showed that LAP had greater accuracy in predicting diabetes events occurring within the next 2-12 years in females than males with more consistent predictive thresholds in females.

Conclusions

This study highlighted a significant gender difference in the association between LAP and future diabetes risk. The risk of diabetes associated with LAP was greater in females than in males. Furthermore, LAP showed superior predictive ability for diabetes at different time points in the future in females and had more consistent and stable predictive thresholds in females, particularly in the medium and long term.

The importance of exercise for glycemic control in type 2 diabetes

Exercise is a first-line therapy recommended for patients with type 2 diabetes (T2D). Although moderate to vigorous exercise (e.g. 150 min/wk) is often advised alongside diet and/or behavior modification, exercise is an independent treatment that can prevent, delay or reverse T2D. Habitual exercise, consisting of aerobic, resistance or their combination, fosters improved short- and long-term glycemic control. Recent work also shows high-intensity interval training is successful at lowering blood glucose, as is breaking up sedentary behavior with short-bouts of light to vigorous movement (e.g. up to 3min). Interestingly, performing afternoon compared with morning as well as post-meal versus pre-meal exercise may yield slightly better glycemic benefit. Despite these efficacious benefits of exercise for T2D care, optimal exercise recommendations remain unclear when considering, dietary, medication, and/or other behaviors.

Bidirectional causal associations between type 2 diabetes and COVID-19

Observational studies have reported high comorbidity between type 2 diabetes (T2D) and severe COVID-19. However, the causality between T2D and COVID-19 has yet to be validated. We performed genetic correlation and Mendelian randomization (MR) analyses to assess genetic relationships and potential causal associations between T2D and three COVID-19 outcomes (severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2] infection, COVID-19 hospitalization, and critical COVID-19). Molecular pathways connecting SARS-CoV-2 and COVID-19 were reconstructed to extract insights into the potential mechanisms underlying the connection. We identified a high genetic overlap between T2D and each COVID-19 outcome (genetic correlations 0.21-0.28). The MR analyses indicated that genetic liability to T2D confers a causal effect on hospitalized COVID-19 (odds ratio 1.08, 95% confidence interval [CI] 1.04-1.12) and critical COVID-19 (1.09, 1.03-1.16), while genetic liability to SARS-CoV-2 infection exerts a causal effect on T2D (1.25, 1.00-1.56). There was suggestive evidence that T2D was associated with an increased risk for SARS-CoV-2 infection (1.02, 1.00-1.03), while critical COVID-19 (1.06, 1.00-1.13) and hospitalized COVID-19 (1.09, 0.99-1.19) were associated with an increased risk for T2D. Pathway analysis identified a panel of immunity-related genes that may mediate the links between T2D and COVID-19 at the molecular level. Our study provides robust support for the bidirectional causal associations between T2D and COVID-19. T2D may contribute to amplifying the severity of COVID-19, while the liability to COVID-19 may increase the risk for T2D.

Short-term effects of lifestyle intervention in the reversion to normoglycemia in people with prediabetes

AIMS

To evaluate the short-term effect of lifestyle intervention in people with prediabetes.

METHODS

A stratified multistage sampling method was used in the recruitment of residents of the Jiangsu Province, China in 2017, who had no previous diagnosis of diabetes. Physical examination and laboratory tests were performed, and questionnaires were completed. Those with a prediabetes diagnosis at baseline were included in the cohort and participants were randomized to the intervention group or the control group. The intervention group received a lifestyle intervention strategy, which included exercise, diet and peer educations. The control group received general health education. Participants were followed up in 2018.

RESULTS

A total of 2005 individuals were included in the analysis. At follow-up, there were 516 (36.7%) individuals in the intervention group and 207 (34.5%) individuals in the control group with normal blood glucose levels. The decline in waist circumference and fasting plasma glucose levels was significantly higher in the intervention group than in the control group. This was still observed after adjusting for variables (odds ratio 1.32, P = 0.02). Females or younger individuals who had lower body mass index and plasma glucose levels at baseline were more likely to reverse to normoglycemia at follow-up.

CONCLUSIONS

Compared with a strategy of general health education, a lifestyle intervention strategy could reverse glucose levels to normoglycemia in individuals with prediabetes.

Effect of resistance training with and without caloric restriction on visceral fat: A systemic review and meta-analysis

We performed a systematic review and meta-analysis to investigate the effect of resistance training (RT) with and without caloric restriction (CR) on visceral fat (VF). PubMed and Scopus were searched to identify original articles published through December 2020. Standardized mean differences and 95% confidence intervals (95% CIs) were determined, and separate analyses were conducted for RT versus control, and RT plus CR versus CR only. Thirty-four studies including 38 intervention arms and involving 2285 were included in the meta-analysis. RT effectively reduced VF [-24 (95% CI -0.34 to -0.13), p < 0.001; I²  = 4.17%, p = 0.40; 24 intervention arms] when compared with control. Based on subgroup analyses, reduction in VF was significant for individual with (p = 0.04) and without (p < 0.001) obesity as well as across medium-term (p = 0.001) and long-term (p = 0.002) interventions. Reduction in VF was significant for both middle-age (p = 0.03) and elderly (p = 0.001) adults but was not significant for pediatric (p = 0.08) participants. However, RT plus CR did not indicate superiority effect on VF [0.23 95% CI -0.04 to 0.51, p = 0.09; I²  = 58.76%, p = 0.003; 14 intervention arms] when compared with CR only. Our results confirm that RT may be effective for reducing VF, but adding RT with CR was not associated with a greater effect for reducing VF.

Two weeks of moderate intensity locomotor training increased corticosterone concentrations but did not alter the number of adropin-immunoreactive cells in the hippocampus of diabetic type 2 and control rats

Adropin (ADR) plays a role in metabolism regulation and its alterations in obesity and diabetes have been found. Treatment with ADR was beneficial in metabolic diseases, and physical exercise increased ADR concentrations in obese patients. However, data on the distribution of ADR in the brain are sparse. The role of metabolic status and physical exercise on its expression in the brain is undiscovered. We hypothesized that diabetes type 2 (DM2) and/or exercise will alter number of ADR-immunoractive (-ir) cells in the rat brain. Animals were divided into groups: diabetes type 2 (receiving high-fat diet and injections of streptozotocin) and control (fed laboratory chow diet; C). Rats were further divided into: running group (2 weeks of forced exercise on a treadmill) and non-running group. Body mass, metabolic and hormonal profiles were assessed. Immunohistochemistry was run to study ADR-ir cells in the brain. We found that: 1) in DM2 animals, running decreased insulin and increased glucose concentrations; 2) in C rats, running decreased insulin concentrations and had no effect on glucose concentration in blood; 3) running increased corticosterone (CORT) concentrations in DM2 and C rats; 4) ADR-ir cells were detected in the hippocampus and ADR-ir fibers in the arcuate nucleus of the hypothalamus, which is a novel location; 5) metabolic status and running, however, did not change number of these cells. We concluded that 2 weeks of forced moderate intensity locomotor training induced stress response present as increased concentration of CORT and did not influence number of ADR-ir cells in the brain.

Obesity and Cardiovascular Disease: A Scientific Statement From the American Heart Association

The global obesity epidemic is well established, with increases in obesity prevalence for most countries since the 1980s. Obesity contributes directly to incident cardiovascular risk factors, including dyslipidemia, type 2 diabetes, hypertension, and sleep disorders. Obesity also leads to the development of cardiovascular disease and cardiovascular disease mortality independently of other cardiovascular risk factors. More recent data highlight abdominal obesity, as determined by waist circumference, as a cardiovascular disease risk marker that is independent of body mass index. There have also been significant advances in imaging modalities for characterizing body composition, including visceral adiposity. Studies that quantify fat depots, including ectopic fat, support excess visceral adiposity as an independent indicator of poor cardiovascular outcomes. Lifestyle modification and subsequent weight loss improve both metabolic syndrome and associated systemic inflammation and endothelial dysfunction. However, clinical trials of medical weight loss have not demonstrated a reduction in coronary artery disease rates. In contrast, prospective studies comparing patients undergoing bariatric surgery with nonsurgical patients with obesity have shown reduced coronary artery disease risk with surgery. In this statement, we summarize the impact of obesity on the diagnosis, clinical management, and outcomes of atherosclerotic cardiovascular disease, heart failure, and arrhythmias, especially sudden cardiac death and atrial fibrillation. In particular, we examine the influence of obesity on noninvasive and invasive diagnostic procedures for coronary artery disease. Moreover, we review the impact of obesity on cardiac function and outcomes related to heart failure with reduced and preserved ejection fraction. Finally, we describe the effects of lifestyle and surgical weight loss interventions on outcomes related to coronary artery disease, heart failure, and atrial fibrillation.

Dietary restriction and/or exercise training impairs spermatogenesis in normal rats

Dietary restriction and/or exercise has been shown to have multiple benefits for health. However, its effects on reproductive health and the mechanisms by which it regulates reproductive function remain unclear. Here, to evaluate its effects on spermatogenesis and sperm function, rats were divided into 4 groups: ad libitum-fed sedentary control, dietary restriction (DR), exercise training (ET), and dietary restriction plus exercise training (DR+ET) groups. Results indicated that body weight, epididymal fat pad weight, and sperm counts were significantly reduced in the DR, ET, and DR+ET groups. Moreover, sperm motility and capacitation-associated protein tyrosine phosphorylation were suppressed in the DR and DR+ET groups, but not the ET group. Microarray analysis revealed that the number of downregulated genes was higher than that of upregulated genes in the DR and/or ET groups. About half of the downregulated genes are common after exercise training and/or diet restriction. Gene ontology analysis showed that downregulated genes in the DR, ET, and DR+ET groups affected spermatogenesis through overlapping pathways, including glucocorticoid, corticosteroid, extracellular structure organization, and estradiol responses. Our findings suggest that diet restriction and/or exercise training may present potential risks to male reproductive dysfunction by disrupting normal gene expression patterns in the testis. Novelty: Dietary restriction and/or exercise can lead to the damage of spermatogenesis as well as sperm maturation. Sperm functional changes are more sensitive to dietary restriction than exercise training. Dietary restriction and exercise impair spermatogenesis through overlapping biological pathways in the testis.

Reversal of Prediabetes in Saudi Adults: Results from an 18 Month Lifestyle Intervention

Aim: This 18 month intervention study aims to determine the efficacy of a lifestyle modification program on prediabetes reversal among Saudi adults. Methods: An 18 month randomized, multicenter trial was conducted among Saudis with prediabetes aged 25–60 recruited from King Salman Hospital and primary care centers in Riyadh, Saudi Arabia. A total of 180 consenting individuals were randomized (1:1) to receive either intensive lifestyle intervention (ILIG) or guidance (control group, CG). ILIG was provided with a personalized lifestyle counseling by nutritionists every 3 months to improve diet and exercise behaviors. CG was given booklets containing information on prediabetes and its prevention. Data from lifestyle assessments and laboratory measurements were analyzed at baseline and every 6 months. The primary outcome was the reversal rate of prediabetes. Results: 158 participants were analyzed (CG:85, ILIG:73) at the 12 month follow-up and 28 participants (CG:11 and ILIG:17) completed the entire 18 month study. Post-intervention, the cumulative incidence of prediabetes reversal in the ILIG was 38 participants (52.1%) which was significantly higher than CG with 26 participants (30.6%) (p = 0.02). Conclusion: A tailored lifestyle intervention is effective in reversing prediabetes, at least for a year, among Arab adults with prediabetes. The challenge of sustaining interest in adopting lifestyle changes for a longer duration should be addressed in this population.

Efficacy of lifestyle interventions in the reversion to normoglycemia in Korean prediabetics: One-year results from a randomised controlled trial

AIM

This study aimed to determine the efficacy of personalized lifestyle interventions on the reversion of a prediabetic state to normoglycemia compared with regular blood glucose testing alone in prediabetes.

METHODS

A randomized, multicenter trial was conducted in prediabetes aged 30-70 with fasting blood glucose level of 5.6-6.9mmol/L (100-125mg/dL) and/or HbA1c level of 39-46mmol/mol (5.7-6.4%) recruited from health checkups at 16 health-promotion centers in Korea. The 799 recruited individuals were randomized to either the personalized lifestyle intervention group (LIG) or the control group (CG) by a computer generated random number list prepared by an independent statistician. The CG was provided with fasting blood glucose and HbA1c tests alone every 3months during the first year. The LIG was provided not only blood glucose test but five sessions of personalized lifestyle counseling by nutritionists every 3months during the first year aimed at improving the diet, alcohol and exercise behaviors. Data from lifestyle assesments and laboratory measurements were analyzed at 1-year after baseline. The primary outcome was the reversion rate from prediabetes to normoglycemia. Additional outcome include the effect of the lifestyle intervention program on lifestyle changes in the LIG to support primary outcome.

RESULTS

The 799 participants randomly allocated to the LIG (n=398) or the CG (n=401). For the analyses of outcomes, 629 participants (313 men and 316 women; mean age, 53.7±9.4years; mean body mass index (BMI), 24.7kg/m²) were included: 325 in the LIG; 304 in the CG. Diet (7.03, 95% CI=4.56-10.86, P<0.001), alcohol (2.24, 95% CI=1.48-3.41, P<0.001), and exercise behaviors (1.85, 95% CI=1.31-2.63, P<0.001) were improved relative to baseline by the personalized lifestyle intervention in the LIG after adjusting age, sex, and family history of diabetes. In terms of main outcome, the cumulative incidence of reversion from prediabetes to normoglycemia at the first year was 37.9% (123/325) [95% CI=32.6-43.1%] in the LIG and 29.6% (90/304) (95% CI=24.5-34.7%) in the CG. After adjustment for age, sex, family history of diabetes, BMI, blood pressure, and lipids, the hazard ratio for reverting to normoglycemia remained significantly higher in the LIG (1.40, 95% CI=1.06-1.83, P=0.017) than in the CG.

CONCLUSION

Personalized lifestyle intervention could be more effective compared with regular blood glucose testing alone in the reversion of a prediabetic state to normoglycemia in Korean prediabetics. This finding suggests that diabetes prevention care would be benefited by incorporating personalized lifestyle counseling. This study was registered at cris.nih.go.kr (KCT0001580).

The impact of high BMI on acute changes in body composition following 90 minutes of running

OBJECTIVES

Although physical activity ameliorates the metabolic impact of high body mass index (BMI), runners with BMI≥25 kg/m² are relatively understudied.This study had two goals: 1) Identify differences in body composition, as measured by dual X-ray absorptiometry (DXA), between overweight (BMI≥25 kg/m²) runners (OWR) and normal weight (BMI<25 kg/m²) runners (NWR) and 2) Examine whether an 90 minute run alters total or regional fat mass, as measured by DXA, in OWR and NWR. We hypothesized that OWR would have higher total body fat than NWR and OWR with greater changes in visceral fat after a prolonged run.

DESIGN

Body composition analysis before and after a supervised run.

METHODS

We recruited NWR (n=16,F:n=7,28.1±1.4 years, BMI 22.0±0.4 kg/m², results as mean±SE) and OWR (n=11,F:n=7,32.0±1.6 years, BMI 30.5±1.4kg/m²) participants. DXA based body composition was measured before and after a supervised, 90 minute run at 60% heart rate reserve.

RESULTS

OWR had higher body fat than NWR in all measured regions.. Both groups did not significantly reduce fat mass at any measured fat depots after the running exposure.

CONCLUSIONS

OWR had higher body fat in all measured regions than NWR. DXA could not demonstrate any acute fat mass changes after a prolonged run.

Carbohydrate-Restriction with High-Intensity Interval Training: An Optimal Combination for Treating Metabolic Diseases?

Lifestyle interventions incorporating both diet and exercise strategies remain cornerstone therapies for treating metabolic disease. Carbohydrate-restriction and high-intensity interval training (HIIT) have independently been shown to improve cardiovascular and metabolic health. Carbohydrate-restriction reduces postprandial hyperglycemia, thereby limiting potential deleterious metabolic and cardiovascular consequences of excessive glucose excursions. Additionally, carbohydrate-restriction has been shown to improve body composition and blood lipids. The benefits of exercise for improving insulin sensitivity are well known. In this regard, HIIT has been shown to rapidly improve glucose control, endothelial function, and cardiorespiratory fitness. Here, we report the available evidence for each strategy and speculate that the combination of carbohydrate-restriction and HIIT will synergistically maximize the benefits of both approaches. We hypothesize that this lifestyle strategy represents an optimal intervention to treat metabolic disease; however, further research is warranted in order to harness the potential benefits of carbohydrate-restriction and HIIT for improving cardiometabolic health.

Effectiveness of Exercise on Visceral Adipose Tissue in Older South Asian Women

INTRODUCTION

Individuals of South Asian (SA) origin have a greater risk for type 2 diabetes and cardiovascular disease than other ethnic populations. This increased risk is in part explained by the unique obesity phenotype of elevated visceral adipose tissue (VAT) among this population. Aerobic exercise in Europeans is effective at reducing VAT, but this has not been studied in SA, who have some of the lowest levels of physical activity in the world. Therefore, the purpose of this study was to determine whether exercise can reduce VAT given the unique obesity phenotype and associated disease risk in the SA population.

METHODS

A total of 75 physically inactive, postmenopausal SA women were randomized to either culturally based (Bhangra dance), standard (gym-based), or control (nonexercise) program for 12-wk. The primary outcome was change in VAT.

RESULTS

The average attendance in the culturally based and standard program was 78% ± 33% and 67% ± 25%, respectively. After an intention-to-treat analysis, VAT was not significantly reduced in culturally based (-60 cm, 95% confidence interval [CI] = -172 to 54, P = 0.300) or standard (-98 cm, 95% CI = -216 to 21, P = 0.106) exercise compared with control after adjustment for baseline physical activity and age. In those participants who attended more than two-thirds of the exercise classes, VAT was significantly reduced compared with control (-109 cm, 95% CI = -204 to -13, P = 0.026).

CONCLUSION

In intention-to-treat analysis VAT was not significantly reduced after 12 wk of either standard or culturally based exercise. However, attendance in both standard and culturally based exercise was high, and VAT was significantly reduced among SA women who adhered to these programs.

Physical Activity and Abnormal Blood Glucose Among Healthy Weight Adults

INTRODUCTION

Physical activity has been linked to prevention and treatment of prediabetes and diabetes in overweight and obese adults. This study examines the relationship between low physical activity levels and risk of abnormal blood glucose (prediabetes or undiagnosed diabetes) in healthy weight adults.

METHODS

Data from the 2014 Health Survey for England were analyzed in July 2016, focusing on adults with a BMI ≥18.5 and <25 who had never been diagnosed with diabetes (N=1,153). Abnormal blood glucose was defined as hemoglobin A1c ≥5.7. Physical activity was measured through the International Physical Activity Questionnaire. Bivariate analyses and Poisson models were conducted on the effect of physical activity on abnormal blood glucose, controlling for age, sex, waist to hip ratio, sitting time, age X physical activity interaction, sex X physical activity, and race.

RESULTS

Abnormal blood glucose was detected in 23.7% of individuals with low activity levels, 14.8% of those with medium activity levels, and 12.2% of those with high activity levels (p<0.003). Similarly, 25.4% of inactive individuals (physically active for <30 minutes per week) were more likely to have abnormal blood glucose levels than active individuals (13.4%, p<0.0001). Higher physical activity was associated with a lower likelihood of abnormal blood glucose in an adjusted Poisson regression.

CONCLUSIONS

Among healthy weight adults, low physical activity levels are significantly associated with abnormal blood glucose (prediabetes and undiagnosed diabetes). These findings suggest that healthy weight individuals may benefit from physical exercise.

Diet and exercise in the management of obstructive sleep apnoea and cardiovascular disease risk

Obstructive sleep apnoea (OSA) is associated with increased cardiovascular disease (CVD) morbidity and mortality. It is accepted that OSA and obesity commonly coexist. The American Academy of Sleep Medicine recommends dietary-induced weight loss and exercise as lifestyle treatment options for OSA. However, most clinical trials upon which this recommendation is based have focused on establishing the effectiveness of calorie-restricted, often low-fat diets for improving OSA severity, whereas less attention has been given to the means through which weight loss is achieved (e.g. altered dietary quality) or whether diet or exercise mediates the associations between reduced weight, improved OSA severity and the CVD substrate. The current evidence suggests that the benefits of a low-carbohydrate or Mediterranean diet in overweight and obese individuals go beyond the recognised benefits of weight reduction. In addition, exercise has an independent protective effect on vascular health, which may counter the increased oxidative stress, inflammation and sympathetic activation that occur in OSA patients. This review aims to expand our understanding of the effects of diet and exercise on OSA and associated CVD complications, and sets the stage for continued research designed to explore optimal lifestyle strategies for reducing the CVD burden in OSA patients.

High-intensity aerobic interval training improves aerobic fitness and HbA1c among persons diagnosed with type 2 diabetes

PURPOSE

It remains to be established how high-intensity aerobic interval training (HAIT) affects risk factors associated with type 2 diabetes (TD2). This study investigated effects of HAIT on maximal oxygen uptake (VO_2max), glycated Hemoglobin type A1C (HbA1c), insulin resistance (IR), fat oxidation (FatOx), body weight (BW), percent body fat (%BF), lactate threshold (LT), blood pressure (BP), and blood lipid profile (BLP) among persons with T2D. Results were compared to the effects after a moderate-intensity training (MIT) program.

METHODS

Thirty-eight individuals with T2D completed 12 weeks of supervised training. HAIT consisted of 4 × 4 min of walking or running uphill at 85-95% of maximal heart rate, and MIT consisted of continuous walking at 70-75% of maximal heart rate.

RESULTS

A 21% increase in VO_2max (from 25.6 to 30.9 ml kg^-1 min^-1, p < 0.001), and a reduction in HbA1c by -0.58% points (from 7.78 to 7.20%, p < 0.001) was found in HAIT. BW and body mass index (BMI) was reduced by 1.9% (p < 0.01). There was a tendency towards an improved FatOx at 60% VO_2max (14%, p = 0.065). These improvements were significant different from MIT. Both HAIT and MIT increased velocity at LT, and reduced %BF, waist circumference, hip circumference, and BP, with no significant differences between the two groups. Correlations were found between change in VO_2max and change in HbA1c when the two intervention groups were combined (R = -0.52, p < 0.01).

CONCLUSION

HAIT is an effective exercise strategy to improve aerobic fitness and reduce risk factors associated with T2D.

Exercise and ectopic fat in type 2 diabetes: A systematic review and meta-analysis

Ectopic adipose tissue surrounding the intra-abdominal organs (visceral fat) and located in the liver, heart, pancreas and muscle, is linked to cardio-metabolic complications commonly experienced in type 2 diabetes. A systematic review and meta-analysis was performed to determine the effect of exercise on ectopic fat in adults with type 2 diabetes. Relevant databases were searched to February 2016. Included were randomised controlled studies, which implemented≥4 weeks of aerobic and/or resistance exercise and quantified ectopic fat via magnetic resonance imaging, computed tomography, proton magnetic resonance spectroscopy or muscle biopsy before and after intervention. Risk of bias and study quality was assessed using Egger's funnel plot test and modified Downs and Black checklist, respectively. Of the 10,750 studies retrieved, 24 were included involving 1383 participants. No studies were found assessing the interaction between exercise and cardiac or pancreas fat. One study assessed the effect of exercise on intramyocellular triglyceride concentration. There was a significant pooled effect size for the meta-analysis comparing exercise vs. control on visceral adiposity (ES=-0.21, 95% CI: -0.37 to -0.05; P=0.010) and a near-significant pooled effect size for liver steatosis reduction with exercise (ES=-0.28, 95% CI: -0.57 to 0.01; P=0.054). Aerobic exercise (ES=-0.23, 95% CI: -0.44 to -0.03; P=0.025) but not resistance training exercise (ES=-0.13, 95% CI: -0.37 to 0.12; P=0.307) was effective for reducing visceral fat in overweight/obese adults with type 2 diabetes. These data suggest that exercise effectively reduces visceral and perhaps liver adipose tissue and that aerobic exercise should be a key feature of exercise programs aimed at reducing visceral fat in obesity-related type 2 diabetes. Further studies are required to assess the relative efficacy of exercise modality on liver fat reduction and the effect of exercise on pancreas, heart, and intramyocellular fat in type 2 diabetes and to clarify the effect of exercise on ectopic fat independent of weight loss.

The impact of duration on effectiveness of exercise, the implication for periodization of training and goal setting for individuals who are overfat, a meta-analysis

Given the assumption that all methods of exercise, e.g., endurance (ET), resistance (RT), or combination of both (E+R), can induce a beneficial effect size (ES) for changes in body composition and health status of individuals who are overfat. Thus the aim and purpose of this study is to evaluate the current body of knowledge to address the question as to the impact that the duration of exercise has on its relative effectiveness for inducing health and body compositional changes in individuals who are overfat to assist with developing periodized exercise protocols and establishing short and long term goals. A tiered meta-analysis of 92-studies and 200-exercise groupings were used for establishing pooled ES within and between groupings based on the increments of 4-week of duration and study designs of ≤8, 9-16, 17-23, 24-36, and ≥36 weeks. Analysis based on random-effect of response indicates a continuum of effectiveness within and between ET, RT and E+R based on duration. Where beneficial effectiveness is not indicated for any measures until after 8-weeks of continuous training with progressive effectiveness being noted in changes to cardiorespiratory fitness, inflammatory cytokines, and alteration of metabolic status from 12-weeks through 32-weeks of continuous training. Results indicate a greater ES for RT and E+R versus ET early in intervention that equalizes with longer durations. Supporting the use of RT and E+R within a periodized program. And secondarily, goals should be established first on performance gains and second body composition or health status modifications for the individual who is overfat.

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.

A systematic review and meta-analysis on the effects of exercise training versus hypocaloric diet: distinct effects on body weight and visceral adipose tissue

Exercise training ('exercise') and hypocaloric diet ('diet') are frequently prescribed for weight loss in obesity. Whilst body weight changes are commonly used to evaluate lifestyle interventions, visceral adiposity (VAT) is a more relevant and stronger predictor for morbidity and mortality. A meta-analysis was performed to assess the effects of exercise or diet on VAT (quantified by radiographic imaging). Relevant databases were searched through May 2014. One hundred seventeen studies (n = 4,815) were included. We found that both exercise and diet cause VAT loss (P < 0.0001). When comparing diet versus training, diet caused a larger weight loss (P = 0.04). In contrast, a trend was observed towards a larger VAT decrease in exercise (P = 0.08). Changes in weight and VAT showed a strong correlation after diet (R(2)  = 0.737, P < 0.001), and a modest correlation after exercise (R(2)  = 0.451, P < 0.001). In the absence of weight loss, exercise is related to 6.1% decrease in VAT, whilst diet showed virtually no change (1.1%). In conclusion, both exercise and diet reduce VAT. Despite a larger effect of diet on total body weight loss, exercise tends to have superior effects in reducing VAT. Finally, total body weight loss does not necessarily reflect changes in VAT and may represent a poor marker when evaluating benefits of lifestyle-interventions.

The Anti-Inflammatory Actions of Exercise Training

The list of diseases with a known inflammatory etiology is growing. Cardiovascular disease, osteoporosis, diabetes, geriatric cachexia, and Alzheimer's disease have all been shown to be linked to or exacerbated by aberrantly regulated inflammatory processes. Nevertheless, there is mounting evidence that those who are physically active, or who become physically active, have a reduction in biomarkers associated with chronic inflammation. There was strong early consensus that exercise-induced reductions in inflammation were explained by body mass index or body fatness, but recent studies provide support for the contention that exercise has body fat-independent anti-inflammatory effects. With few exceptions, the anti-inflammatory effects of exercise appear to occur regardless of age or the presence of chronic diseases. What remains unclear are the mechanisms by which exercise training induces these anti-inflammatory effects, but there are several intriguing possibilities, including release of endogenous products, such as heat shock proteins; selective reduction of visceral adipose tissue mass or reducing infiltration of adipocytes by macrophages; shift in immune cell phenotype; cross-tolerizing effects; or exercise-induced shifts in accessory proteins of toll-like receptor signaling. However, future research endeavors are likely to uncover additional potential mechanisms, and it could be some time before functional mechanisms are made clear. In summary, the potential anti-inflammatory influences of exercise training may provide a low-cost, readily available, and effective treatment for low-grade systemic inflammation and could contribute significantly to the positive effects of exercise training on chronic disease.

Exercise Modulates Oxidative Stress and Inflammation in Aging and Cardiovascular Diseases

Despite the wealth of epidemiological and experimental studies indicating the protective role of regular physical activity/exercise training against the sequels of aging and cardiovascular diseases, the molecular transducers of exercise/physical activity benefits are not fully identified but should be further investigated in more integrative and innovative approaches, as they bear the potential for transformative discoveries of novel therapeutic targets. As aging and cardiovascular diseases are associated with a chronic state of oxidative stress and inflammation mediated via complex and interconnected pathways, we will focus in this review on the antioxidant and anti-inflammatory actions of exercise, mainly exerted on adipose tissue, skeletal muscles, immune system, and cardiovascular system by modulating anti-inflammatory/proinflammatory cytokines profile, redox-sensitive transcription factors such as nuclear factor kappa B, activator protein-1, and peroxisome proliferator-activated receptor gamma coactivator 1-alpha, antioxidant and prooxidant enzymes, and repair proteins such as heat shock proteins, proteasome complex, oxoguanine DNA glycosylase, uracil DNA glycosylase, and telomerase. It is important to note that the effects of exercise vary depending on the type, intensity, frequency, and duration of exercise as well as on the individual's characteristics; therefore, the development of personalized exercise programs is essential.

Consequences of obesity and weight loss: a devil's advocate position

Obesity is associated with multiple negative health consequences and current weight management guidelines recommend all obese persons to lose weight. However, recent evidence suggests that not all obese persons are negatively affected by their weight and that weight loss does not necessarily always improve health. The purpose of this review is not to trivialize the significant health risks associated with obesity, but to discuss subpopulations of obese people who are not adversely affected, or may even benefit from higher adiposity, and in who weight loss per se may not always be the most appropriate recommendation. More specifically, this review will take a devil's advocate position when discussing the consequences of obesity and weight loss for adults with established cardiovascular disease and type 2 diabetes, weight cyclers, metabolically healthy obese adults, youth, older adults and obese individuals who are highly fit.

Effect of different exercise intensities on the pancreas of animals with metabolic syndrome

INTRODUCTION

Metabolic syndrome (MS) comprises several metabolic disorders that are risk factors for cardiovascular disease and has its source connected to the accumulation of visceral adipose tissue (VAT) and development of insulin resistance. Despite studies showing beneficial results of exercise on several risk factors for cardiovascular disease, studies evaluating the effects of different intensities of exercise training on the pancreas with experimental models are scarce.

METHODS

In total, 20 Wistar rats were used, divided into four groups: control (C), metabolic syndrome (MS and without exercise), metabolic syndrome and practice of walking (MSWalk), and metabolic syndrome and practice of running (MSRun). The applied procedures were induction of MS by fructose in drinking water; experimental protocol of walking and running; weighing of body mass and VAT; sacrifice of animals with blood collection and removal of organs and processing of samples for light microscopy using the analysis of volume densities (Vv) of the studied structures.

RESULTS

Running showed a reduction of VAT weight (-54%), triglyceride levels (-40%), Vv[islet] (-62%), Vv[islet.cells] (-22%), Vv[islet.insterstitial] (-44%), and Vv[acinar.insterstitial] (-24%) and an increase of Vv[acini] (+21%) and Vv[acinar.cells] (+22%). Regarding walking, we observed a decrease of VAT weight (-34%) and triglyceride levels (-27%), an increase of Vv[islet.cells] (+72%) and Vv[acinar.cells] (+7%), and a decrease of Vv[acini] (-4%) and Vv[acinar.insterstitial] (-16%) when compared with those in the MS group.

CONCLUSION

Our results suggest that the experimental model with low-intensity exercise (walking) seems to be more particularly recommended for preventing morphological and metabolic disorders occurring in the MS.

Effect of Walking Exercise on Changes in Cardiorespiratory Fitness, Metabolic Syndrome Markers, and High-molecular-weight Adiponectin in Obese Middle-aged Women

[Purpose] The purpose of this study was to assess the effect of a 24-week exercise intervention on cardiorespiratory fitness, metabolic syndrome markers, and high-molecular-weight (HMW) adiponectin among obese middle-aged women. [Subjects] The subjects were 14 obese middle-aged women. [Methods] The exercise program involved walking at 50–60% of the maximum oxygen consumption, 3 times a week, for 24 weeks. Body composition analysis, blood pressure measurements, and blood analysis were performed before the exercise program and at weeks 6, 12, 18, and 24. [Results] The results showed that after 24 weeks in the exercise program, the obesity indices and metabolic risk factors, namely, weight, body fat, body mass index, waist circumference, systolic blood pressure, diastolic blood pressure, and triglycerides decreased significantly, whereas HDLC, a metabolic improvement factor, increased significantly. Additionally, VO_2max increased significantly, together with the level of total and HMW adiponectins. Correlation analysis of the changes in measured variables (∆ score) during resulting from the 24-week exercise program showed that body fat had a significant negative correlation and VO_2max had a significant positive correlation with HMW adiponectin. [Conclusion] Among obese middle-aged women, regular exercise increases cardiorespiratory fitness and HMW adiponectin expression and therefore can be effective in the prevention and treatment of obesity and metabolic syndrome.

Niacin increased glucose, insulin, and C-peptide levels in sedentary nondiabetic postmenopausal women

The current study examined the effects of niacin and a single bout of aerobic exercise on plasma glucose, insulin, and C-peptide in sedentary, nondiabetic postmenopausal women. As a crossover design, 17 participants underwent four different trials: rest during the no-niacin condition (R), exercise during the no-niacin condition (E), rest during the with-niacin condition (RN), and exercise during the with-niacin condition (EN). All participants took 1,000 mg/day of extended-release niacin for 4 weeks during the with-niacin conditions (RN and EN). The exercise treatment consisted of a single bout of treadmill walking at 60% heart rate reserve until 400 kcal were expended. Blood samples were collected at 24 hours after each trial and analyzed for changes in plasma glucose, insulin, and C-peptide. A two by two analysis of variance was used to examine the changes in dependent variables, and the Bonferroni adjustment was employed as the post hoc test. The level of statistical significance was set at P<0.05. There was no significant interaction between exercise and niacin, nor was there a main effect of exercise for changes in glucose, insulin, or C-peptide. However, there was a significant main effect for niacin as mean glucose, insulin, and C-peptide values significantly increased with niacin; glucose increased 10.6% (P=0.001), from 95.03±10.67 mg/dL to 105.07±13.56 mg/dL; insulin increased 61.8% (P=0.001), from 16.98±12.49 μU/mL to 27.48±14.84 μU/mL; and C-peptide increased 46.1% (P=0.001), from 1.65±0.75 ng/mL to 2.41±0.97 ng/mL. Although niacin was generally well tolerated, given its adverse effects on glucose, insulin, and C-peptide profiles, the use of niacin should be done so with caution and under medical supervision.

Steps ahead: a randomized trial to reduce unhealthy weight gain in the Lower Mississippi Delta

OBJECTIVE

The Lower Mississippi Delta (LMD) region of the United States is characterized by high levels of obesity and physical inactivity. The objective was to test the effectiveness of adapting the 2010 Dietary Guidelines for Americans (DG), with and without a physical activity (PA) component, for attenuating weight gain.

METHODS

Overall, 121 white and African-American adults (35-64 years; body mass index 25-34.9 kg/m(2)) were randomized to a DG only group (n = 61) or a DG + PA group (n = 60). Both groups received a 12-week dietary education and behavior change intervention. The DG + PA group also received PA education and a pedometer. Changes in weight (kg), %weight, and waist circumference (WC; cm) were determined. Analyses considered all completers (n = 99) and those who engaged with ≥80% of the intervention (n = 83). General linear models compared mean changes between groups after adjustment for baseline values, race, and sex.

RESULTS

Weight, %weight, and WC significantly decreased from baseline to follow-up in both groups (p < 0.05; unadjusted values). Adjusted analysis showed a main effect of group for weight (p = 0.041) and %weight (p = 0.047) in the completers analysis, and WC (p = 0.046) in the ≥80% attendance analysis, with the DG + PA group improving weight-related outcomes more.

CONCLUSIONS

Low-burden behavioral interventions could be effective strategies in attenuating unhealthy weight gain in the LMD.

Effect of exercise on abdominal fat loss in men and women with and without type 2 diabetes

OBJECTIVE

To examine the effect of exercise on abdominal adipose tissue in adults with and without type 2 diabetes mellitus (T2DM).

DESIGN

Post hoc analysis of two randomised controlled trials.

SETTING

Outpatient secondary prevention programme in Baltimore, Maryland, USA.

PARTICIPANTS

97 men and women with prehypertension, stage 1 or medically controlled hypertension. 49% of the sample was also diagnosed with T2DM.

INTERVENTION

All participants completed a 26-week (6.5 months) supervised aerobic and resistance exercise programme following American College of Sports Medicine guidelines.

PRIMARY AND SECONDARY OUTCOME MEASURES

The main outcomes in this post hoc analysis were total abdominal adipose tissue (TAT), subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) measured by MRI. Secondary outcomes were to determine whether the magnitude of abdominal fat change differed by diabetes status in men and women and to identify the predictors of change in abdominal fat distribution with exercise.

RESULTS

Overall, participants (mean age 61±6 years; 45% women) significantly improved peak oxygen uptake by 15% (p<0.01) and reduced weight by 2% (p<0.01). No change in SAT was observed after training. The reduction in VAT following exercise was attenuated in participants with T2DM (-3%) compared with participants who were non-T2DM (-18%, p<0.001 for the difference in change). The magnitude of VAT loss was associated with a decrease in body weight (r=0.50, p<0.001). After adjustment for weight change using regression analysis, diabetes status remained an independent predictor of the change in VAT.

CONCLUSIONS

Although participants with and without T2DM attained an exercise training effect as evidenced by increased fitness, VAT was unchanged in T2DM compared to those without T2DM, suggesting that these individuals may be resistant to this important benefit of exercise. The strategies for reducing cardiovascular disease risk in T2DM may be most effective when they include a weight loss component.

CLINICAL TRIALS REGISTRATION

Clinicaltrials.gov Registry NCT00212303.

Changes in body fat distribution and fitness are associated with changes in hemoglobin A1c after 9 months of exercise training: results from the HART-D study

OBJECTIVE

To investigate the associations between changes in body composition and fitness after exercise training and changes in hemoglobin A1c (HbA1c) in individuals with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Participants (n = 201) were randomized to aerobic, resistance, or combined training for 9 months. HbA1c, waist circumference, total and trunk fat mass, appendicular fat mass, lean body mass, isokinetic leg muscle strength, peak O2 uptake, and estimated METs were assessed at baseline and follow-up. Change in HbA1c was evaluated across quartiles of change in body composition and fitness.

RESULTS

Change in HbA1c was associated with changes in body weight (r = 0.13, P = 0.052), waist circumference (r = 0.17, P = 0.013), trunk fat mass (r = 0.19, P = 0.005), and estimated METs (r = -0.16, P = 0.023). There was a trend in change in HbA1c across quartiles of waist circumference (P = 0.011), trunk fat mass (P = 0.020), and estimated METs (P = 0.011). Participants with increased estimated METs and reduced trunk fat mass had greater odds of having reduced HbA1c after training (3.48, 1.46-8.31). Finally, participants with increased estimated METs and reduced waist circumference were 2.81 (1.13-6.98) times more likely to have reduced HbA1c and type 2 diabetes medication use than those without improved fitness and central adiposity.

CONCLUSIONS

In patients with type 2 diabetes, a reduction in central adiposity and increase in fitness were the most prominent predictors of the change in HbA1c in response to exercise training.

Obesity, adiposity, and dyslipidemia: a consensus statement from the National Lipid Association

The term "fat" may refer to lipids as well as the cells and tissue that store lipid (ie, adipocytes and adipose tissue). "Lipid" is derived from "lipos," which refers to animal fat or vegetable oil. Adiposity refers to body fat and is derived from "adipo," referring to fat. Adipocytes and adipose tissue store the greatest amount of body lipids, including triglycerides and free cholesterol. Adipocytes and adipose tissue are active from an endocrine and immune standpoint. Adipocyte hypertrophy and excessive adipose tissue accumulation can promote pathogenic adipocyte and adipose tissue effects (adiposopathy), resulting in abnormal levels of circulating lipids, with dyslipidemia being a major atherosclerotic coronary heart disease risk factor. It is therefore incumbent upon lipidologists to be among the most knowledgeable in the understanding of the relationship between excessive body fat and dyslipidemia. On September 16, 2012, the National Lipid Association held a Consensus Conference with the goal of better defining the effect of adiposity on lipoproteins, how the pathos of excessive body fat (adiposopathy) contributes to dyslipidemia, and how therapies such as appropriate nutrition, increased physical activity, weight-management drugs, and bariatric surgery might be expected to impact dyslipidemia. It is hoped that the information derived from these proceedings will promote a greater appreciation among clinicians of the impact of excess adiposity and its treatment on dyslipidemia and prompt more research on the effects of interventions for improving dyslipidemia and reducing cardiovascular disease risk in overweight and obese patients.

Effect of exercise on blood pressure in type 2 diabetes: a randomized controlled trial

BACKGROUND

Increased blood pressure (BP) in type 2 diabetes (T2DM) markedly increases cardiovascular disease morbidity and mortality risk compared to having increased BP alone.

OBJECTIVE

To investigate whether exercise reduces suboptimal levels of untreated suboptimal BP or treated hypertension.

DESIGN

Prospective, randomized controlled trial for 6 months.

SETTING

Single center in Baltimore, MD, USA.

PATIENTS

140 participants with T2DM not requiring insulin and untreated SBP of 120-159 or DBP of 85-99 mmHg, or, if being treated for hypertension, any SBP <159 mmHg or DBP<99 mmHg; 114 completed the study.

INTERVENTION

Supervised exercise, 3 times per week for 6 months compared with general advice about physical activity.

MEASUREMENTS

Resting SBP and DBP (primary outcome); diabetes status, arterial stiffness assessed as carotid-femoral pulse-wave velocity (PWV), body composition and fitness (secondary outcomes).

RESULTS

Overall baseline BP was 126.8 ± 13.5 / 71.7 ± 9.0 mmHg, with no group differences. At 6 months, BP was unchanged from baseline in either group, BP 125.8 ± 13.2 / 70.7 ± 8.8 mmHg in controls; and 126.0 ± 14.2 / 70.3 ± 9.0 mmHg in exercisers, despite attaining a training effects as evidenced by increased aerobic and strength fitness and lean mass and reduced fat mass (all p<0.05), Overall baseline PWV was 959.9 ± 333.1 cm/s, with no group difference. At 6-months, PWV did not change and was not different between group; exercisers, 923.7 ± 319.8 cm/s, 905.5 ± 344.7, controls.

LIMITATIONS

A completion rate of 81 %.

CONCLUSIONS

Though exercisers improve fitness and body composition, there were no reductions in BP. The lack of change in arterial stiffness suggests a resistance to exercise-induced BP reduction in persons with T2DM.

Effects of high-intensity exercise training on body composition, abdominal fat loss, and cardiorespiratory fitness in middle-aged Korean females

The primary purpose of this study was to investigate the effects of high-intensity exercise training under relatively equal energy expenditure on whole body fat and abdominal fat loss, and cardiorespiratory fitness. Twenty-two untrained middle-aged Korean females were randomized into one of the following groups: control, low-intensity training group (LI), and high-intensity training group (HI). Subjects completed 14 weeks of training at 50% maximal oxygen consumption (LI) or 70% maximal oxygen consumption (HI) with the volume of exercise equated relative to kilograms of body weight. Weekly exercise volumes were 13.5 METs⋅h/week for the first 4 weeks, 18 METs⋅h/week for next 5 weeks, and 22.5 METs⋅h/week for the final 5 weeks. Data were analyzed using 2-way repeated measures ANOVA with post hoc test, using Bonferroni's correction. HI showed significant reductions in fat mass (p < 0.05), total abdominal fat (p < 0.01), and subcutaneous abdominal fat (p < 0.01). LI reduced total abdominal fat (p < 0.05), but there were no other significant changes found in the control or LI groups. Maximal oxygen consumption was enhanced in both HI and LI with no significant group difference. High-density lipoprotein cholesterol increased significantly in HI (p < 0.05). IL-6, C-reactive protein, TNF-α, and other blood lipids were unaltered following training. Results indicate that high-intensity exercise training is more beneficial in whole body and abdominal fat loss; however, cardiorespiratory enhancement shows a dose-response relationship with weekly exercise volume. It is suggested that 14 weeks of aerobic exercise training at either high- or low-intensity is not sufficient enough to induce changes in levels of inflammatory proteins.

Effects of a culturally grounded community-based diabetes prevention program for obese Latino adolescents

PURPOSE

The purpose of this study was to test the feasibility and preliminary effects of a culturally grounded, community-based diabetes prevention program among obese Latino adolescents.

METHODS

Fifteen obese Latino adolescents (body mass index [BMI] percentile = 96.3 ± 1.1, age = 15.0 ± 0.9 years) completed a 12-week intervention that included weekly lifestyle education classes delivered by bilingual/bicultural promotoras and three, 60-minute physical activity sessions per week. Participants were assessed for anthropometrics (height, weight, BMI, and waist circumference), cardiorespiratory fitness, physical activity/inactivity, nutrition behaviors, and insulin sensitivity and glucose tolerance by a 2-hour oral glucose tolerance test.

RESULTS

The intervention resulted in significant decreases in BMI z score, BMI percentile, and waist circumference; increases in cardiorespiratory fitness; and decreases in physical inactivity and dietary fat consumption. In addition to these changes, the intervention led to significant improvements in insulin sensitivity and reductions in 2-hour glucose levels.

CONCLUSIONS

These results support the feasibility and efficacy of a community-based diabetes prevention program for high-risk Latino youth. Translational approaches that are both culturally grounded and biologically meaningful represent a novel and innovative strategy for closing the obesity-related health disparities gap.

Effects of aerobic exercise intensity on abdominal and thigh adipose tissue and skeletal muscle attenuation in overweight women with type 2 diabetes mellitus

BACKGROUND

We investigated the effects of exercise intensity on abdominal and mid-thigh adipose tissue, attenuation of skeletal muscle, and insulin sensitivity in overweight women with type 2 diabetes mellitus (T2DM).

METHODS

Twenty-eight patients were randomly assigned to control (CG, n=12), moderate intensity exercise (MEG, n=8), or vigorous intensity exercise (VEG, n=8) group. Subjects in both exercise groups completed a 12-week exercise program (MEG, 3.6 to 5.2 METs; VEG, ≥5.2 METs) that was monitored by accelerometers. We assessed body mass index (BMI), total fat area (TFA), visceral fat area (VFA), subcutaneous fat area (SFA), mid-thigh intramuscular adipose tissue (TIMAT), total skeletal muscle (TTM), low density skeletal muscle (TLDM), and normal density skeletal muscle (TNDM) using computed tomography, and measured insulin sensitivity with an insulin tolerance test (K(ITT)), before and after the intervention.

RESULTS

At baseline, the mean age was 53.8±7.9 years, duration of diabetes was 3.8±2.3 years, and BMI was 26.6±2.6 kg/m(2). After 12 weeks, the percent change (%C) in BMI, TIMAT, and TLDM were not different among three groups. However, %C in TFA and VFA were significantly reduced in MEG compared to CG (P=0.026 and P=0.008, respectively). %C SFA was significantly reduced in VEG compared to CG (P=0.038) and %C TTM, TNDM, and K(ITT) were significantly increased in VEG compared to the CG (P=0.044, P=0.007, and P=0.016, respectively).

CONCLUSION

Although there was no difference in the change in BMI among groups, TFA and VFA were more reduced in MEG, and only VEG increased TTM, TNDM, and insulin sensitivity compared to CG.

Physical activity and exercise in the regulation of human adipose tissue physiology

Physical activity and exercise are key components of energy expenditure and therefore of energy balance. Changes in energy balance alter fat mass. It is therefore reasonable to ask: What are the links between physical activity and adipose tissue function? There are many complexities. Physical activity is a multifaceted behavior of which exercise is just one component. Physical activity influences adipose tissue both acutely and in the longer term. A single bout of exercise stimulates adipose tissue blood flow and fat mobilization, resulting in delivery of fatty acids to skeletal muscles at a rate well-matched to metabolic requirements, except perhaps in vigorous intensity exercise. The stimuli include adrenergic and other circulating factors. There is a period following an exercise bout when fatty acids are directed away from adipose tissue to other tissues such as skeletal muscle, reducing dietary fat storage in adipose. With chronic exercise (training), there are changes in adipose tissue physiology, particularly an enhanced fat mobilization during acute exercise. It is difficult, however, to distinguish chronic "structural" changes from those associated with the last exercise bout. In addition, it is difficult to distinguish between the effects of training per se and negative energy balance. Epidemiological observations support the idea that physically active people have relatively low fat mass, and intervention studies tend to show that exercise training reduces fat mass. A much-discussed effect of exercise versus calorie restriction in preferentially reducing visceral fat is not borne out by meta-analyses. We conclude that, in addition to the regulation of fat mass, physical activity may contribute to metabolic health through beneficial dynamic changes within adipose tissue in response to each activity bout.

A systematic review and meta-analysis of the effect of aerobic vs. resistance exercise training on visceral fat

It is increasingly recognized that the location of excess adiposity, particularly increased deposition of visceral adipose tissue (VAT), is important when determining the adverse health effects of overweight and obesity. Exercise therapy is an integral component of obesity management, but the most potent exercise prescription for VAT benefit is unclear. We aimed to evaluate the independent and synergistic effects of aerobic exercise (AEx) and progressive resistance training (PRT) and to directly compare the efficacy of AEx and PRT for beneficial VAT modulation. A systematic review and meta-analysis was performed to assess the efficacy of exercise interventions on VAT content/volume in overweight and obese adults. Relevant databases were searched to November 2010. Included studies were randomized controlled designs in which AEx or PRT in isolation or combination were employed for 4 weeks or more in adult humans, where computed tomography (CT) or magnetic resonance imaging (MRI) was used for quantification of VAT pre- and post-intervention. Of the 12196 studies from the initial search, 35 were included. After removal of outliers, there was a significant pooled effect size (ES) for the comparison between AEx therapy and control (-0.33, 95% CI: -0.52 to -0.14; P < 0.01) but not for the comparison between PRT therapy and control (0.09, 95% CI: -0.17 to -0.36; P = 0.49). Of the available nine studies which directly compared AEx with PRT, the pooled ES did not reach statistical significance (ES = 0.23, 95% CI: -0.02 to 0.50; P = 0.07 favouring AEx). The pooled ES did not reach statistical significance for interventions that combined AEx and PRT therapy vs. control (-0.28, 95% CI: -0.69 to 0.14; P = 0.19), for which only seven studies were available. These data suggest that aerobic exercise is central for exercise programmes aimed at reducing VAT, and that aerobic exercise below current recommendations for overweight/obesity management may be sufficient for beneficial VAT modification. Further investigation is needed regarding the efficacy and feasibility of multi-modal training as a means of reducing VAT.

A Cross-Sectional Analysis of the Association between Physical Activity and Visceral Adipose Tissue Accumulation in a Multiethnic Cohort

Higher levels of VAT at the same body size and lower levels of physical activity (PA) have been reported in persons of Chinese and South Asian origin compared to European origin. The purpose of this study was to test the hypothesis that higher levels of VAT in persons of Chinese and South Asian origin versus European origin are associated with lower levels of PA. Chinese, European, and South Asian participants were assessed for sociodemographics, obesity-related measures, anthropometrics, and PA. Bivariate correlations, analysis of covariance, and regression models were used to explore ethnic differences in PA and the role of PA in explaining obesity-related measures. We observed ethnic differences in both body fat distribution and PA. Chinese and South Asians had higher amounts of VAT at a given BMI but lower amounts of moderate PA, vigorous PA, and moderate-to-vigorous PA (MVPA). Furthermore, we found ethnic-specific differences in the associations between body fat distribution and PA with only Europeans showing a consistent negative relationship between body fat distribution and PA. When ethnic differences in PA were taken into account, there were no longer any differences in VAT between the Chinese and European groups, while VAT remained higher in South Asians than Europeans.

Do overweight and obese individuals select a "moderate intensity" workload when asked to do so?

The purpose of this study was (1) to determine if overweight/obese individuals (age 26-50 y) would self-select moderate exercise intensity when asked to do so and (2) to determine how this self-selected workload compared to exercising at a workload (60% peak aerobic capacity) that is known to provide cardioprotective health benefits. Oxygen consumption (VO(2)) and energy expenditure were measured in 33 men/women (BMI ≥ 27 kg/m(2)) who completed two 30 min walking bouts: (1) self-selected walking pace on an indoor track and (2) prescribed exercise pace (60% VO(2) peak) on a treadmill. The data revealed that (1) the prescribed intensity was 6% higher than the self-selected pace and elicited a higher energy expenditure (P < 0.05) than the self-selected pace (+83 kJ); (2) overweight subjects walked at a slightly lower percentage of VO(2) peak than the obese subjects (P < 0.05); (3) men walked at a lower percentage of VO(2) peak than the women (P < 0.05). In conclusion when asked to walk at a moderate intensity, overweight/obese individuals tended to select a lower workload in the "moderate intensity" range which could be maintained for 30 min; however, a higher intensity which would be more cardioprotective could not be maintained for 30 min by most individuals.

Evidence-based risk assessment and recommendations for physical activity clearance: diabetes mellitus and related comorbidities1This paper is one of a selection of papers published in this Special Issue, entitled Evidence-based risk assessment and recommendations for physical activity clearance, and has undergone the Journal’s usual peer review process

Physical activity (PA) is one of the most powerful treatment options for persons with prediabetes or diabetes. However, some elevation in risk occurs with increased PA, at least initially, and certain precautions need to be made to lower these risks, particularly if these persons are unaccustomed to exercise. We conducted a standardized search of all adverse events associated with increased PA in persons with prediabetes or diabetes (type 1 or type 2) and provided evidence-based guidelines on PA screening in these apparently high-risk individuals. A systematic literature review was performed of all studies reporting on adverse events in persons with prediabetes or diabetes. Studies included were from all designs (retrospective and prospective including randomized controlled trials) and were assessed according to evaluation criteria adapted by a consensus panel. A total of 47 studies, involving >8000 individuals, were deemed eligible. A number of these studies identified a range of mild to severe acute risks with exercise (musculoskeletal injury, hypoglycemia, foot ulceration, proliferative retinopathy, hypotension, sudden death) but the overall prevalence was low. Based on several randomized controlled trials and prospective studies in which prescribed exercise was performed at a wide range of intensities, it appears that increased PA is a relatively safe procedure with no evidence of a loss of life. Based on our assessment of the available literature, we provide a new PA risk algorithm for persons with prediabetes and diabetes and comment on the role of the patient, the qualified exercise professional, and the patient’s physician in the risk screening process.