Improved glucose tolerance after high-load strength training in patients undergoing dialysis

Nurses' and medical doctors' attitudes towards exercise for people with chronic kidney disease in Denmark

BACKGROUND

Implementation of exercise training in people with kidney failure may be affected by clinicians' attitudes.

OBJECTIVES

To investigate Danish nephrology nurses' and medical doctors' attitudes towards: exercise for people undergoing dialysis; use of physical activity interventions in chronic kidney disease; and to compare Danish and previously reported Australian nurse attitudes.

DESIGN

Cross-sectional survey.

PARTICIPANTS

Nurses and medical doctors from the nephrology field in Denmark.

MEASUREMENTS

The questionnaire attitudes towards exercise in dialysis, and questions about exercise advice, counselling and interventions.

RESULTS

Nephrology nurses (n = 167) and 17 medical doctors (women 92%, age 47 ± 11 years) from 19 dialysis units participated. There were no differences between nurses' and medical doctors attitudes about training. Ninety-five % and 88% of nurses and medical doctors, respectively, agreed that most people undergoing dialysis could benefit from exercise. Exercise training was offered to people undergoing haemodialyses in 88% of 17 departments. Danish nurses reported more positive attitudes than Australian towards exercise (p < 0.05). Ninety-five % and 86% of the Danish and Australian nurses, respectively, agreed/strongly agreed that most people undergoing dialysis could benefit from exercise. Six % and 35% of the Danish and Australian nurses, respectively, agreed/strongly agreed that most people with dialysis were too sick to exercise.

CONCLUSION

Danish nephrology nurses and medical doctors had mostly positive attitudes to exercise training to people undergoing dialysis, and exercise to people with dialysis was offered frequently. Danish and Australian nurses had positive attitudes to exercise to people undergoing dialysis, it was however more positive in Danish nurses.

Exercise and chronic kidney disease: potential mechanisms underlying the physiological benefits

Increasing evidence indicates that exercise has beneficial effects on chronic inflammation, cardiorespiratory function, muscle and bone strength and metabolic markers in adults with chronic kidney disease (CKD), kidney failure or kidney transplants. However, the mechanisms that underlie these benefits have received little attention, and the available clinical evidence is mainly from small, short-duration (<12 weeks) exercise intervention studies. The available data, mainly from patients with CKD or on dialysis, suggest that exercise-mediated shifts towards a less inflammatory immune cell profile, enhanced activity of the NRF2 pathway and reduced monocyte infiltration into adipose tissue may underlie improvements in inflammatory biomarkers. Exercise-mediated increases in nitric oxide release and bioavailability, reduced angiotensin II accumulation in the heart, left ventricular remodelling and reductions in myocardial fibrosis may contribute to improvements in left ventricular hypertrophy. Exercise stimulates an anabolic response in skeletal muscle in CKD, but increases in mitochondrial mass and satellite cell activation seem to be impaired in this population. Exercise-mediated activation of the canonical wnt pathway may lead to bone formation and improvements in the levels of the bone-derived hormones klotho and fibroblast growth factor 23 (FGF23). Longer duration studies with larger sample sizes are needed to confirm these mechanisms in CKD, kidney failure and kidney transplant populations and provide evidence for targeted exercise interventions.

Sex Difference in the Association between Physical Activity and All-Cause Mortality in Ambulatory Patients with Chronic Kidney Disease

(1) Background: The purpose of this article was to investigate the association between self-reported physical activity (PA) and all-cause mortality in ambulatory patients with chronic kidney disease (CKD), stage 4–5 including maintenance dialysis. (2) Methods: Ambulatory patients with CKD (eGFR < 30 mL/min/1.73 m²) with conservative treatment or chronic dialysis were included. PA was assessed using the Saltin–Grimby Physical Activity Level Scale. A Cox proportional hazards regression model––adjusted for age, sex, plasma–albumin, body mass index, socioeconomic status, and treatment––was applied. (3) Results: Participants (n = 374) were followed 39 ± 15 months from entry to death or censoring. Throughout the study period of 39 months, 156 deaths (42%) were registered. Regarding physical activity, 128 (34%) of the participants were inactive, 212 (57%) were moderately active, and 34 (9%) were highly or vigorously active. Moderate PA was associated with a decreased mortality risk in women (n = 150) compared to inactivity (HR 0.27 (0.15; 0.51), p < 0.001), whereas a high/vigorous level of PA was not significantly associated with mortality risk compared to inactivity. In men (n = 224), the associations between PA levels and mortality risk were not significant. (4) Conclusions: Moderate PA was associated with reduced all-cause mortality in ambulatory women with stage 4–5 CKD with or without maintenance dialysis treatment. Physical activity was not significantly associated with mortality in men.

Effects of dynamic and isometric resistance training protocols on metabolic profile in hemodialysis patients: a randomized controlled trial

The aim of this study was to compare the effect of dynamic (DRT) and isometric (IRT) resistance training on glycemic homeostasis, lipid profile, and nitric oxide (NO) in hemodialysis (HD) patients. Patients were randomly distributed into 3 groups: control (n = 65), DRT (n = 65), and IRT (n = 67). Patients assessed before and after the intervention period were tested for fasting blood glucose, glycated hemoglobin, oral glucose tolerance test, insulin resistance, lipid profile, leptin, insulin, adiponectin, C-reactive protein, and NO . Patients underwent to strength and body composition assessments. Subjects allocated in both DRT and IRT groups took part in a 24-week resistance training program, 3 times per week. Each training session was approximately 1 hour before dialysis and consisted of 3 sets of 8-12 repetitions at low intensity. Total workload was higher in the DRT as compared with the IRT. This heightened workload related to better glycemic homeostasis in HD patients as measured by regulation of insulin, adiponectin, and leptin, while improveing triglycerides, free-fat mass, and muscle strength. Additionally, NO levels were increased in the DRT group. NO was significantly correlated with glucose intolerance (r = -0.42, p = 0.0155) and workload (r = 0.46, p = 0.0022). The IRT group only improved strength (p < 0.05). Twenty-four weeks of DRT improved glycemic homeostasis, lipid profile, and NO in HD patients. Although IRT seems to play an important role in increasing strength, DRT might be a better choice to promote metabolic adjustments in HD patients. Clinical trial: http://www.ensaiosclinicos.gov.br/rg/RBR-3gpg5w. Novelty: DRT might be a better choice for metabolic improvements in patients with chronic kidney disease (CKD). Exercise-training might treat metabolic imbalance in CKD patients.

The effects of circuit resistance training on plasma progranulin level, insulin resistance and body composition in obese men

Background Progranulin (PGRN) is implicated in obesity and insulin resistance (IR). The aim of this study was to evaluate the effects of 8 weeks of circuit resistance training (CRT) on plasma PGRN, IR and body composition in obese men. Materials and methods Twenty-eight healthy obese men [age: 36 ± 7.7 years, body weight (BW): 96.4 ± 15.6 kg, body mass index (BMI): 32.4 ± 4.5 kg/m2] completed the study. Subjects were randomly assigned to two groups of control and training. Subjects in the training group underwent training for 8 weeks, 3 times a week. Blood samples and anthropometric characteristics were taken before the commencement of the exercise protocol and 72 h after the last training session. The homeostatic model assessment of insulin resistance (HOMA-IR) was used to measure IR. Results BW, BF%, BMI, waist-hip ratio (WHR), HOMA-IR and plasma PGRN levels except lean body mass (LBM) were significantly reduced in the training group (p < 0.05). Additionally, except for LBM, subjects in the training group had significantly decreased BW, BF%, BMI, WHR, HOMA-IR and plasma PGRN levels compared to changes in those in the control group (p < 0.05). Significant correlations were found between the changes in plasma PGRN and the changes in insulin, HOMA-IR and BMI (p < 0.05). Conclusions The findings showed that 8 weeks of CRT improved body composition and IR which were accompanied by reduced plasma PGRN levels. This study suggests that CRT has the potential for obese individuals to counteract obesity-associated health impairments.

Chronic Exercise Improves Mitochondrial Function and Insulin Sensitivity in Brown Adipose Tissue

The aim of the present work was to study the consequences of chronic exercise training on factors involved in the regulation of mitochondrial remodeling and biogenesis, as well as the ability to produce energy and improve insulin sensitivity and glucose uptake in rat brown adipose tissue (BAT). Male Wistar rats were divided into two groups: (1) control group (C; n = 10) and (2) exercise-trained rats (ET; n = 10) for 8 weeks on a motor treadmill (five times per week for 50 min). Exercise training reduced body weight, plasma insulin, and oxidized LDL concentrations. Protein expression of ATP-independent metalloprotease (OMA1), short optic atrophy 1 (S-OPA1), and dynamin-related protein 1 (DRP1) in BAT increased in trained rats, and long optic atrophy 1 (L-OPA1) and mitofusin 1 (MFN1) expression decreased. BAT expression of nuclear respiratory factor type 1 (NRF1) and mitochondrial transcription factor A (TFAM), the main factors involved in mitochondrial biogenesis, was higher in trained rats compared to controls. Exercise training increased protein expression of sirtuin 1 (SIRT1), peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α) and AMP-activated protein kinase (pAMPK/AMPK ratio) in BAT. In addition, training increased carnitine palmitoyltransferase II (CPT II), mitochondrial F1 ATP synthase α-chain, mitochondrial malate dehydrogenase 2 (mMDH) and uncoupling protein (UCP) 1,2,3 expression in BAT. Moreover, exercise increased insulin receptor (IR) ratio (IRA/IRB ratio), IRA-insulin-like growth factor 1 receptor (IGF-1R) hybrids and p42/44 activation, and decreased IGF-1R expression and IR substrate 1 (p-IRS-1) (S307) indicating higher insulin sensitivity and favoring glucose uptake in BAT in response to chronic exercise training. In summary, the present study indicates that chronic exercise is able to improve the energetic profile of BAT in terms of increased mitochondrial function and insulin sensitivity.

Physical Activity in Patients Treated With Peritoneal Dialysis: A Systematic Review and Meta-analysis

BACKGROUND

Exercise has been shown to be of benefit in the general population and in patients with chronic diseases. Despite a lack of compelling evidence, patients with end-stage kidney disease (ESKD) treated with peritoneal dialysis (PD) are often discouraged from participating in exercise programs that include weight lifting due to concerns about the development of hernias and leaks. The actual effects of physical activity with or without structured exercise programs for patients on PD remain unclear.

OBJECTIVE

To determine the risks and benefits of physical activity in the ESKD population treated with PD.

DESIGN

Systematic review and meta-analysis.

SETTING

Included all studies that met our criteria regardless of country of origin.

PATIENTS

Adult patients with ESKD treated with PD.

MEASUREMENTS

Descriptive and quantitative analysis of our primary and secondary outcome variables.

METHODS

We searched MEDLINE, Embase, CINAHL, and Cochrane Central Register of Controlled Trials for observational and interventional studies examining the effects of physical activity in patients on PD. A systematic review and meta-analysis was conducted of the identified studies. The primary outcomes of interest included patient-centered outcomes of mental health, physical functioning, fatigue, quality of life, and adverse events. Secondary outcomes included nutritional measures, lipid profile, blood pressure changes, maximum heart rate, resting heart rate, maximal oxygen consumption, muscle development, cognitive function, and markers of inflammation.

RESULTS

Of 1828 studies identified by the literature search, 12 met the inclusion criteria including 6 interventional and 6 observational studies. There was limited information on the patient important outcomes. However, there is some evidence for improvements in burden of kidney disease, physical function, and some mental health measures with physical activity.

LIMITATIONS

Lack of well-designed randomized controlled trials impaired our ability to determine the benefits and risks of increasing physical activity.

CONCLUSIONS

There is limited evidence of benefit with increased levels of physical activity in PD patients. Further research is needed to define the exercise program that is likely to be of most benefit to patients treated with PD.

Update on the effects of physical activity on insulin sensitivity in humans

PURPOSE AND METHODS

This review presents established knowledge on the effects of physical activity (PA) on whole-body insulin sensitivity (SI) and summarises the findings of recent (2013-2016) studies.

DISCUSSION AND CONCLUSIONS

Recent studies provide further evidence to support the notion that regular PA reduces the risk of insulin resistance, metabolic syndrome and type 2 diabetes, and SI improves when individuals comply with exercise and/or PA guidelines. Many studies indicate a dose response, with higher energy expenditures and higher exercise intensities, including high intensity interval training (HIIT), producing greater benefits on whole-body SI, although these findings are not unanimous. Aerobic exercise interventions can improve SI without an associated increase in cardiorespiratory fitness as measured by maximal or peak oxygen consumption. Both aerobic and resistance exercise can induce improvements in glycaemic regulation, with some suggestions that exercise regimens including both may be more efficacious than either exercise mode alone. Some studies report exercise-induced benefits to SI that are independent of habitual diet and weight loss, while others indicate an association with fat reduction, hence the debate over the relative importance of PA and weight loss continues. During exercise, muscle contraction stimulated improvements in SI are associated with increases in AMPK activity, which deactivates TCB1D1, promoting GLUT4 translocation to the cell membrane and thereby increasing glucose uptake. Postexercise, increases in Akt deactivate TCB1D4 and thereby increase GLUT4 translocation to the cell membrane. The reduction in intramuscular saturated fatty acids and concomitant reductions in ceramides, but not diacylglycerols, provide a potential link between intramuscular lipid content and SI. Increased skeletal muscle capillarisation provides another independent adaptation through which SI is improved, as does enhanced β cell activity. Recent studies are combining exercise interventions with dietary and feeding manipulations to investigate the potential for augmenting the exercise-induced improvements in SI and glycaemic control.

Fiber type-specific response of skeletal muscle satellite cells to high-intensity resistance training in dialysis patients

INTRODUCTION

The aim of this study was to assess the effect of high-intensity resistance training on satellite cell (SC) and myonuclear number in the muscle of patients undergoing dialysis.

METHODS

Patients (n = 21) underwent a 16-week control period, followed by 16 weeks of resistance training 3 times weekly. SC and myonuclear number were determined by immunohistochemistry of vastus lateralis muscle biopsy cross-sections. Knee extension torque was tested in a dynamometer.

RESULTS

During training, SCs/type I fibers increased by 15%, whereas SCs/type II fibers remained unchanged. Myonuclear content of type II, but not type I, fibers increased with training. Before the control period, the SC content of type II fibers was lower than that of type I fibers, whereas contents were comparable when normalized to fiber area. Torque increased after training.

CONCLUSIONS

Increased myonuclear content of type II muscle fibers of dialysis patients who perform resistance training suggests that SC dysfunction is not the limiting factor for muscle growth.

Interleukin-6 and vitamin D status during high-intensity resistance training in patients with chronic kidney disease

Background. The aim of this study was to investigate IL-6 and 25-hydroxyvitamin D (25-OH D) associations with muscle size and muscle function in dialysis patients. Methods. Patients were included in a 16-week control period followed by 16 weeks of high-intensity resistance training thrice weekly. IL-6 and 25-OH D were analysed after an over-night fast. Muscle fibre size was analysed in biopsies from m. vastus lateralis. Muscle power was tested using a Leg Extensor Power Rig. Results. Patients (n = 36) with IL-6 ≥ 6.49 pg/ml (median) were older and had decreased muscle power and a reduced protein intake (P < 0.05) compared with patients with IL-6 < 6.49 pg/ml. IL-6 was not associated with muscle fibre size. Vitamin D deficiency (25-OH D < 50 nmol/l) was present in 51% of the patients and not associated with muscle power. IL-6 remained unchanged during the training period, whilst muscle power increased by 20-23% (P < 0.001). Conclusion. Elevated IL-6 values were associated with decreased muscle power but not with decreased muscle fibre size. Half of the patients were suffering from vitamin D deficiency, which was not associated with muscle power. IL-6 was unchanged by high-intensity resistance training in dialysis patients in this study.