Effect of a 3-Year Lifestyle Intervention in Patients with Chronic Kidney Disease: A Randomized Clinical Trial.

BACKGROUND: Supervised lifestyle interventions have the potential to significantly improve physical activity and fitness in patients with CKD. METHODS: To assess the efficacy of a lifestyle intervention in patients with CKD to improve cardiorespiratory fitness and exercise capacity over 36 months, we conducted a randomized clinical trial, enrolling 160 patients with stage 3-4 CKD, with 81 randomized to usual care and 79 to a 3-year lifestyle intervention. The lifestyle intervention comprised care from a multidisciplinary team, including a nephrologist, nurse practitioner, exercise physiologist, dietitian, diabetes educator, psychologist, and social worker. The exercise training component consisted of an 8-week individualized and supervised gym-based exercise intervention followed by 34 months of a predominantly home-based program. Self-reported physical activity (metabolic equivalent of tasks [METs] minutes per week), cardiorespiratory fitness (peak O2 consumption [VO2peak]), exercise capacity (maximum METs and 6-minute walk distance) and neuromuscular fitness (grip strength and get-up-and-go test time) were evaluated at 12, 24, and 36 months. RESULTS: The intervention increased the percentage of patients meeting physical activity guideline targets of 500 MET min/wk from 29% at baseline to 63% at 3 years. At 12 months, both VO2peak and METs increased significantly in the lifestyle intervention group by 9.7% and 30%, respectively, without change in the usual care group. Thereafter, VO2peak declined to near baseline levels, whereas METs remained elevated in the lifestyle intervention group at 24 and 36 months. After 3 years, the intervention had increased the 6-minute walk distance and blunted declines in the get-up-and-go test time. CONCLUSIONS: A 3-year lifestyle intervention doubled the percentage of CKD patients meeting physical activity guidelines, improved exercise capacity, and ameliorated losses in neuromuscular and cardiorespiratory fitness.

Creating play opportunities on the school playground: Educator experiences of the Sydney playground project.

INTRODUCTION: Children with disabilities often experience unsupportive environments that restrict their play opportunities and inclusion on the school playground. This exclusion can perpetuate inequities for children with disabilities, with lifelong implications. The Sydney Playground Project uses a simple, innovative intervention consisting of placing recycled materials on the playground and engaging parents and educators in risk reframing sessions to create increased playground choice, control, independence and inclusion for all children. METHODS: The purpose of this study was to learn from participants about the utility of the intervention for promoting choice and control among children with disability on the school playground. Data included evaluative interviews with 27 school staff (teaching assistants, teachers, therapists, school leadership) across five participating schools after completing of the intervention. Analysis was thematic and explored prominent ideas first within schools, and then between schools. RESULTS: Prior to the intervention, participating school staff focused on active supervision to support play and student needs. During the intervention, school staff experienced role shift and confusion as they allowed the children increased independence while using the recycled materials and learned to navigate how much independence to give the children. Children engaged in increased imaginative and social play, and school staff adopted higher expectations of children's capabilities. CONCLUSION: Interventions such as the Sydney Playground Project that collaboratively shift adult perceptions to focus on the capabilities of children with disabilities and increase the supportiveness of the physical environment have great promise in increasing play choice and inclusion on the school playground.

The effects of vigorous intensity exercise in the third trimester of pregnancy: a systematic review and meta-analysis.

BACKGROUND: Fetal growth is dependent upon utero-placental vascular supply of oxygen and nutrients from the mother and has been proposed to be compromised by vigorous intensity exercise in the third trimester. The aim of this systematic review was to investigate the effects of vigorous intensity exercise performed throughout pregnancy, on infant and maternal outcomes. METHODS: Electronic searching of the PubMed, Medline, EMBASE, Cochrane Library, Web of Science and CINAHL databases was used to conduct the search up to November 2018. Study designs included in the systematic review were randomised control trials, quasi-experimental studies, cohort studies and case-control studies. The studies were required to include an intervention or report of pregnant women performing vigorous exercise during gestation, with a comparator group of either lower intensity exercise or standard care. RESULTS: Ten cohort studies (n = 32,080) and five randomized control trials (n = 623) were included in the systematic review (n = 15), with 13 studies included in the meta-analysis. No significant difference existed in birthweight for infants of mothers who engaged in vigorous physical activity and those who lacked this exposure (mean difference = 8.06 g, n = 8006). Moreover, no significant increase existed in risk of small for gestational age (risk ratio = 0.15, n = 4504), risk of low birth weight (< 2500 g) (risk ratio = 0.44, n = 2454) or maternal weight gain (mean difference = - 0.46 kg, n = 1834). Women who engaged in vigorous physical activity had a small but significant increase in length of gestational age before delivery (mean difference = 0.21 weeks, n = 4281) and a small but significantly reduced risk of prematurity (risk ratio = - 0.20, n = 3025). CONCLUSIONS: Findings from this meta-analysis indicate that vigorous intensity exercise completed into the third trimester appears to be safe for most healthy pregnancies. Further research is needed on the effects of vigorous intensity exercise in the first and second trimester, and of exercise intensity exceeding 90% of maximum heart rate. TRIAL REGISTRATION: PROSPERO trial registration CRD42018102109 .

High-intensity interval training in chronic kidney disease: A randomized pilot study.

INTRODUCTION: High-intensity interval training (HIIT) increases mitochondrial biogenesis and cardiorespiratory fitness in chronic disease populations, however has not been studied in people with chronic kidney disease (CKD). The aim of this study was to compare the feasibility, safety, and efficacy of HIIT with moderate-intensity continuous training (MICT) in people with CKD. METHODS: Fourteen individuals with stage 3-4 CKD were randomized to 3 supervised sessions/wk for 12 weeks, of HIIT (n = 9, 4 × 4 minute intervals, 80%-95% peak heart rate [PHR]) or MICT (n = 5, 40 minutes, 65% PHR). Feasibility was assessed via session attendance and adherence to the exercise intensity. Safety was examined by adverse event reporting. Efficacy was determined from changes in cardiorespiratory fitness (VO2 peak), exercise capacity (METs), and markers of mitochondrial biogenesis (PGC1α protein levels), muscle protein catabolism (MuRF1), and muscle protein synthesis (p-P70S6k Thr389 ). RESULTS: Participants completed a similar number of sessions in each group (HIIT = 33.0[7.0] vs MICT = 33.5[3.3] sessions), and participants adhered to the target heart rates. There were no adverse events attributable to exercise training. There was a significant time effect for exercise capacity (HIIT = +0.8 ± 1.2; MICT = +1.3 ± 1.6 METs; P = 0.01) and muscle protein synthesis (HIIT = +0.6 ± 1.1; MICT = +1.4 ± 1.7 au; P = 0.04). However, there were no significant (P > 0.05) group × time effects for any outcomes. CONCLUSION: This pilot study demonstrated that HIIT is a feasible and safe option for people with CKD, and there were similar benefits of HIIT and MICT on exercise capacity and skeletal muscle protein synthesis. These data support a larger trial to further evaluate the effectiveness of HIIT.

Construct Validity and Test-Retest Reliability of the Coping Inventory (CI) for Children With Developmental Disabilities.

OBJECTIVE: A reliable, valid, and readily usable method of measuring coping is essential for occupational therapy practitioners and researchers working with children with developmental disabilities. The aim of this study was to examine evidence for the construct validity and internal and test-retest reliability of the Coping Inventory (CI), a 48-item survey designed for use with children. METHOD: School staff (N = 39) completed CIs for 79 students with developmental disabilities age 5-13 yr (mean = 8.0, standard deviation = 2.0) who were primarily boys (n = 52; 68%) with autism spectrum disorder (n = 40 of 47 diagnoses provided). We used Rasch analysis to examine construct validity, internal reliability, and possible redundancy of items and intraclass correlations, Pearson correlations, Bland-Altman plots, and t tests were used to examine test-retest reliability. RESULTS: Rasch analysis provided evidence of construct validity: All items correlated positively with the overall measure; data from 94% of items conformed with Rasch expectations, and the items form a logical hierarchy. Intraclass correlations revealed an average coefficient of .96, providing evidence of test-retest reliability. CONCLUSION: The CI demonstrated good evidence for construct validity and internal and test-retest reliability. Redundancy of items suggests that some items could be eliminated after further research.

Agreement between cystatin-C and creatinine based eGFR estimates after a 12-month exercise intervention in patients with chronic kidney disease.

BACKGROUND: Estimation of GFR (eGFR) using formulae based on serum creatinine concentrations are commonly used to assess kidney function. Physical exercise can increase creatinine turnover and lean mass; therefore, this method may not be suitable for use in exercising individuals. Cystatin-C based eGFR formulae may be a more accurate measure of kidney function when examining the impact of exercise on kidney function. The aim of this study was to assess the agreement of four creatinine and cystatin-C based estimates of GFR before and after a 12-month exercise intervention. METHODS: One hundred forty-two participants with stage 3-4 chronic kidney disease (CKD) (eGFR 25-60 mL/min/1.73 m2) were included. Subjects were randomised to either a Control group (standard nephrological care [n = 68]) or a Lifestyle Intervention group (12 months of primarily aerobic based exercise training [n = 74]). Four eGFR formulae were compared at baseline and after 12 months: 1) MDRDcr, 2) CKD-EPIcr, 3) CKD-EPIcys and 4) CKD-EPIcr-cys. RESULTS: Control participants were aged 63.5[9.4] years, 60.3% were male, 42.2% had diabetes, and had an eGFR of 40.5 ± 8.9 ml/min/1.73m2. Lifestyle Intervention participants were aged 60.5[14.2] years, 59.5% were male, 43.8% had diabetes, and had an eGFR of 38.9 ± 8.5 ml/min/1.73m2. There were no significant baseline differences between the two groups. Lean mass (r = 0.319, p < 0.01) and grip strength (r = 0.391, p < 0.001) were associated with serum creatinine at baseline. However, there were no significant correlations between cystatin-C and the same measures. The Lifestyle Intervention resulted in significant improvements in exercise capacity (+ 1.9 ± 1.8 METs, p < 0.001). There were no changes in lean mass in both Control and Lifestyle Intervention groups during the 12 months. CKD-EPIcys was considerably lower in both groups at both baseline and 12 months than CKD-EPIcr (Control = - 10.5 ± 9.1 and - 13.1 ± 11.8, and Lifestyle Intervention = - 7.9 ± 8.6 and - 8.4 ± 12.3 ml/min/1.73 m2), CKD-EPIcr-cys (Control = - 3.6 ± 3.7 and - 4.5 ± 4.5, and Lifestyle Intervention = - 3.6 ± 3.7 and - 2.5 ± 5.5 ml/min/1.73 m2) and MDRDcr (Control = - 9.3 ± 8.4 and - 12.0 ± 10.7, Lifestyle Intervention = - 6.4 ± 8.4 and - 6.9 ± 11.2 ml/min/1.73 m2). CONCLUSIONS: In CKD patients participating in a primarily aerobic based exercise training, without improvements in lean mass, cystatin-C and creatinine based eGFR provided similar estimates of kidney function at both baseline and after 12 months of exercise training. TRIAL REGISTRATION: The trial was registered at www.anzctr.org.au (Registration Number ANZCTR12608000337370) on the 17/07/2008 (retrospectively registered).

Association between left ventricular global longitudinal strain, health-related quality of life and functional capacity in chronic kidney disease patients with preserved ejection fraction.

AIM: Patients with chronic kidney disease (CKD) have a significant burden of dyspnoea and fatigue in spite having normal left ventricular (LV) ejection fraction (EF). Global longitudinal strain (GLS) can detect subtle changes in LV function. This study aimed to evaluate the relationship between LV function, functional capacity and quality of life (QOL) in CKD patients with preserved EF. METHODS: A cross-sectional study of patients with stage 3/4 CKD (n = 108). Clinical characteristics, biochemical data, functional capacity (6-min walk test (6MWT), timed up and go (TUG) test) and QOL (short form-12 (SF-12v2™) ) were measured. Echocardiogram was used to assess GLS, EF and diastolic function (E/A, e' and E/e'). RESULTS: The mean age was 58.1 ± 9.9 years, 55.6% were men, estimated glomerular filtration rate was 44.8 ± 10.6 mL/min/1.73 m(2), GLS was -18.5 ± 3.6% and 19.4% had impaired GLS (>-16%). Patients with impaired GLS had a significantly shorter 6MWT and slower TUG test compared with patients with preserved GLS. Bivariate analysis showed GLS and E/e' correlated with distance walked in 6MWT (GLS (r = -0.24, P = 0.02); E/e'(r = -0.38, P = 0.002) ). Following adjustment for potential confounders, GLS remained independently associated with 6MWT (model R(2) = 0.37, P < 0.001). Mean physical component summary scores (PCS) and mental component summary scores (MCS) were 43.0 ± 10.2 and 50.9 ± 9.5. There was no cardiac parameter that was independently associated with PCS. However women, lower systolic blood pressure and GLS was associated with lower MCS (model R(2) = 0.30, P < 0.001). CONCLUSION: GLS was associated with measures of functional capacity and QOL in CKD patients with preserved EF.

Left ventricular global longitudinal strain is associated with cardiovascular risk factors and arterial stiffness in chronic kidney disease.

BACKGROUND: Global longitudinal strain (GLS) has emerged as a superior method for detecting left ventricular (LV) systolic dysfunction compared to ejection fraction (EF) on the basis that it is less operator dependent and more reproducible. The 2-dimensional strain (2DS) method is easily measured and integrated into a standard echocardiogram. This study aimed to determine the relationship between GLS and traditional and chronic kidney disease (CKD)-related risk factors of cardiovascular disease (CVD) in patients with CKD. METHODS: A cross sectional study of patients with moderate CKD stages 3 and 4 (n = 136). Clinical characteristics, anthropometric, biochemical data including markers of inflammation [C-reactive protein (CRP)], uremic toxins [indoxyl sulphate (IS), p-cresyl sulphate (PCS)], and arterial stiffness [pulse wave velocity (PWV)] were measured. Inducible ischemia was detected using exercise stress echocardiogram. GLS was determined from 3 standard apical views using 2-dimensional speckle tracking and EF was measured using Simpson's rule. Associations between GLS and traditional and CKD-related risk factors were explored using multivariate models. RESULTS: The study population parameters included: age 59.4 ± 9.8 years, 58 % male, estimated glomerular filtration rate (eGFR) 44.4 ± 10.1 ml/min/1.73 m(2), GLS -18.3 ± 3.6 % and EF 65.8 % ± 7.8 %. This study demonstrated that GLS correlated with diabetes (r = 0.21, p = 0.01), history of heart failure (r = 0.20, p = 0.01), free IS (r = 0.24, p = 0.005) free PCS (r = 0.23, p = 0.007), body mass index (BMI) (r = 0.28, p < 0.001), and PWV (r = 0.24, p = 0.009). Following adjustment for demographic, baseline co-morbidities and laboratory parameters, GLS was independently associated with free IS, BMI and arterial stiffness (R(2) for model = .30, p < 0.0001). CONCLUSIONS: In the CKD cohort, LV systolic function assessed using GLS was associated with uremic toxins, obesity and arterial stiffness.

The Sydney playground project--levelling the playing field: a cluster trial of a primary school-based intervention aiming to promote manageable risk-taking in children with disability.

BACKGROUND: Providing children and adults with opportunities to engage in manageable risk taking may be a stepping stone toward closing the gap in life conditions currently experienced by young people with disabilities. We aim to demonstrate the effectiveness of a simple, innovative program for 1) changing the way parents and teachers view manageable risk-taking for children with disabilities and 2) increasing the level of responsibility that children take for their own actions, as seen on the school playground. METHODS/DESIGN: We will employ a cluster repeated measures trial with six Sydney-area primary-school-based programs for children with disabilities. The intervention comprises two arms. 1) Risk-reframing--teachers and parents will participate together in small group intervention sessions focusing on the benefits of manageable risk-taking; 2) Introduction of play materials--materials without a defined purpose and facilitative of social cooperation will be introduced to the school playground for children to use at all break times. A control period will be undertaken first for two school terms, followed by two terms of the intervention period. Outcome measures will include playground observations, The Coping Inventory, qualitative field notes, and The Tolerance of Risk in Play Scale. DISCUSSION: New national programs, such as Australia's National Disability Insurance Scheme, will place increasing demands on young people with disabilities to assume responsibility for difficult decisions regarding procuring services. Innovative approaches, commencing early in life, are required to prepare young people and their carers for this level of responsibility. This research offers innovative intervention strategies for promoting autonomy in children with disabilities and their carers. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registration Number ACTRN12614000549628 (registered 22/5/2014).

Maternal physical activity and sitting time and its association with placental morphology and blood flow during gestation: Findings from the Queensland Family Cohort study.

OBJECTIVES: Antenatal exercise is associated with placental morphological alterations, however research in this area is limited. Given the emphasis on the beneficial effects of antenatal exercise, it is important to understand its effect on placental function and the relationship to foetal development. The aim of this study was to investigate the association between physical activity, sitting time, and placental outcomes measured during gestation. DESIGN: Prospective cohort study. METHODS: Pregnant women in the Queensland Family Cohort study self-reported physical activity at 24 and 36 weeks of gestation (n = 203) and were categorised into physical activity volume groups of nil-low (0-<500 metabolic equivalent of task·minutes/week), moderate (500-<1000 metabolic equivalent of task·minutes/week), or high-volume activity (≥1000 metabolic equivalent of task·minutes/week). Participants reported average daily sitting time, whereby excessive sitting time was considered as ≥8h/day. Placental stiffness, thickness, and uteroplacental blood flow resistance were measured by ultrasound imaging at each timepoint. RESULTS: Physical activity volume was not associated with changes to placental morphometrics or uteroplacental blood flow resistance at 24 or 36 weeks of gestation. Excessive sitting time at 36 weeks was associated with greater placental stiffness (p = 0.046), and a lower umbilical artery pulsatility index (p = 0.001). CONCLUSIONS: Placental tissue stiffness and umbilical artery resistance were altered in late gestation with higher maternal sitting time but not with physical activity volume. Overall, excessive sitting time may be a risk for suboptimal placental function and could be an important focus for antenatal care.

The effects of exercise during pregnancy on placental composition: A systematic review and meta-analysis.

INTRODUCTION: Morphological changes to the placenta occur as the demands of the foetus increase throughout gestation. Physical activity during pregnancy is known to benefit both the mother and infant, however the impact of antenatal exercise training on placental development is less known. The aim of this systematic review and meta-analysis was to investigate the effects of exercise training during pregnancy on measures of placental composition. METHODS: Six electronic databases were searched from inception to June 2021 for studies comparing regular antenatal exercise with either usual maternal care or no exercise for its effect on measures of placental morphological composition. Meta-analyses were performed for placental weight and the placental weight to birthweight (PWBW) ratio. RESULTS: Seven randomised controlled trials and two cohort studies were included in the systematic review and meta-analysis (n = 9). There was no significant difference in placental weight (mean difference (MD) = -9.07g, p = 0.42) or the PWBW ratio (MD = 0.00, p = 0.32) between exercise and control groups. Parenchymal tissue volume was higher, represented by an increase in villous tissue, and non-parenchymal volume was lower in women who exercised regularly compared to those that were not exercising during pregnancy. DISCUSSION: Exercise training during pregnancy may not alter placental weight or the PWBW ratio. However, findings from this review indicate that antenatal exercise training can promote advantageous morphological changes to placental tissues.

Longitudinal association of physical activity during pregnancy with maternal and infant outcomes: Findings from the Australian longitudinal study of women's health.

BACKGROUND: Physical activity has known benefits during pregnancy; however, the optimum volume of physical activity through the different stages of pregnancy is not well known. OBJECTIVES: The aims of this study were to investigate the associations of physical activity volume in pregnant women in each trimester of pregnancy with maternal and infant outcomes. DESIGN: The study involved 1657 pregnant women from the Australian Longitudinal Study on Women's Health, who completed surveys from 2006 to 2012 (aged 28-39 years). METHODS: Women reported being in either the first, second or third trimester of pregnancy. Women were grouped into four groups according to their self-reported physical activity during pregnancy: (1) Nil (0-<33.3 MET.min/week), (2) Low (33.3-<500 MET.min/week), (3) Moderate (500-<1000 MET.min/week) and (4) High (⩾1000 MET.min/week). Women who reported their physical activity during pregnancy completed a survey within three years after the birth, relating to outcomes associated with pregnancy and childbirth (gestational diabetes, hypertension, and antenatal depression and anxiety) and infant outcomes (birthweight and prematurity). RESULTS: There was no association of physical activity in any trimester with infant birthweight, prematurity, gestational diabetes, hypertension or antenatal depression. Antenatal anxiety was less prevalent in women who reported low (1.7%) or moderate (1.1%) physical activity than in those who reported no activity (4.7%; p = 0.01). CONCLUSION: Different amounts of physical activity during pregnancy were not associated with the measured adverse health outcomes. However, low and moderate amounts of physical activity were associated with reduced incidence of antenatal anxiety.

A 12-month lifestyle intervention does not improve cardiac autonomic function in patients with chronic kidney disease.

OBJECTIVES: Patients with chronic kidney disease (CKD) are at a high risk of future autonomic dysfunction and cardiovascular disease. The aim of this study was to examine the effects of a 12-month lifestyle intervention (LI) involving regular aerobic exercise on cardiac autonomic function in CKD patients. DESIGN: Pooled exploratory analysis. METHODS: 113 eligible patients with stage 3-4 CKD (eGFR 25-60 ml/min/1.75m2) participated in a LI program, including an 8-week individualised gym-based exercise program followed by a 10-month home-based program. The control (CON) group underwent standard nephrological care. The following parameters were assessed prior to and following the 12-month study period: cardiorespiratory fitness (VO2peak) from a graded exercise test; cardiac autonomic function from time, frequency, and non-linear measures of heart rate variability (HRV), heart rate (HR) recovery following peak exercise, and chronotropic competence during exercise. RESULTS: Compared to the CON group, the LI group significantly increased VO2peak (CON = -1.0 vs. LI = +1.8 ml/kg/min, p < 0.01) while there was no significant improvement in any HRV measure (p = 0.85), HR recovery (p = 0.38) or chronotropic competence (p = 0.28). Changes in relative VO2peak were significantly associated with changes in a non-linear HRV measure, α1 (p < 0.01), independent of age and eGFR (r2 = 0.196, p = 0.03). CONCLUSIONS: Despite the significant increase in cardiorespiratory fitness for the LI group, there were no changes in cardiac autonomic function. However, α1 may be a sensitive measure to assess VO2peak changes in this clinical cohort. Further research is required to investigate the role of different modalities of exercise training to enhance cardiac autonomic function in patients with CKD.

Guidelines for the delivery and monitoring of high intensity interval training in clinical populations.

High intensity interval training (HIIT) is now recognized in international clinical-based exercise guidelines as an appropriate and beneficial adjunct to moderate intensity continuous training. HIIT involves alternating periods of high intensity aerobic exercise with light recovery exercise or no exercise, allowing for greater physiological stimulus and adaptation than moderate intensity continuous training (MICT) for cardiorespiratory fitness and other cardiometabolic processes. However, there is no universal criteria or framework for the prescription and monitoring of HIIT in clinical populations, and safety concerns remain a common barrier for implementing HIIT as standard care. Historically, exercise intensity has been prescribed using heart rate (HR) targets derived from either a predicted maximal HR (HRmax) or from an attempt to objectively measure HRmax. However, using this approach alone has a number of limitations. Here we provide guidelines to improve the delivery of HIIT in cardiometabolic populations using 1) a framework for HIIT prescription using a combination of objective and subjective measures of exercise intensity, and 2) clinical considerations for assessment and monitoring to maximize patient safety. The framework involves an individualized step-by-step process to calculate, validate, and calibrate HR target zones for HIIT training to allow for appropriate workload prescription and progression. We strongly recommend this framework be used in future clinical trials investigating HIIT.

Feasibility of higher intensity exercise in patients with chronic kidney disease.

BACKGROUND: Higher intensity exercise is a more effective way of evoking improvements in cardiorespiratory fitness in many chronic disease populations compared to moderate intensity continuous training. The aim of this study was to investigate the feasibility of participation in higher intensity exercise in patients with chronic kidney disease (CKD). METHODS: This study is an observational sub-study of the intervention arm of a randomized control trial. Forty-four participants with stage 3-4 CKD in the intervention arm were required to complete a predominantly home-based 12 month individualized exercise intervention. Physical activity levels, exercise capacity (METs) and blood biochemistry were measured at baseline and 12 months. The physical activity groups (higher intensity, moderate intensity and not meeting guidelines) were determined from the six months activity prior to the 12 month testing visit. RESULTS: At 12 months, the number of patients who reported performing weekly higher intensity exercise in the previous six months of the intervention increased by 23%. Participants completing higher intensity exercise had a significantly greater exercise capacity at 12 months (11.9±3.7 METs) than participants reporting moderate intensity exercise and those not meeting guidelines (9.2±1.7, 7.6±3.2 METs). Hemoglobin levels and exercise capacity were significantly higher at baseline in patients who reported exercising at higher intensities (142.9±16.1 g/L and 9.8±4.2 METs) compared to those reporting moderate intensity exercise (129.8±12.9 g/L and 8±3.1 METs) and not meeting guidelines (127.3±12.5 g/L and 6±2 METs). CONCLUSIONS: The study was successful in increasing higher intensity physical activity in a large proportion of patients with CKD.

Oxidative stress is associated with decreased heart rate variability in patients with chronic kidney disease.

OBJECTIVES: Elevated oxidative stress and reduced heart rate variability (HRV) is prevalent in patients with chronic kidney disease (CKD) and is associated with increased morbidity and mortality. Previous studies have identified a positive association between elevated oxidative stress and autonomic dysfunction, however this relationship has not yet been investigated in the CKD population. METHODS: Plasma was collected from 78 patients with stage 3-4 CKD (estimated glomerular filtration rate 25-60 ml/min/1.73 m2) for the assessment of oxidative stress, including plasma total F2-isoprostanes, glutathione peroxidase activity and total antioxidant capacity. Time and frequency HRV parameters were measured from a three lead electrocardiogram. RESULTS: Participants with elevated F2-isoprostanes had reduced HRV compared to patients with normal levels of F2-isoprostanes. A number of HRV parameters were found to be inversely correlated with F2-isoprostanes in all CKD patients, including SDNN (r = -0.337; P < 0.01), VLF (r = -0.281, P = 0.01), LF (r = -0.315, P < 0.01) and total power (r = -0.288, P = 0.01). Multiple linear regression found F2-isoprostanes to be an independent predictor of SDNN (r2 = 0.287, ß = -0.272, P = 0.01). DISCUSSION: Oxidative stress is significantly and independently associated with HRV in patients with CKD. Identifying oxidative stress in the pathogenesis of autonomic dysfunction may help target therapeutic strategies.

Effects of exercise and lifestyle intervention on oxidative stress in chronic kidney disease.

OBJECTIVES: Determine the effects of a 12-month exercise and lifestyle intervention program on changes in plasma biomarkers of oxidative stress in pre-dialysis chronic kidney disease (CKD) patients. METHODS: A total of 136 stage 3-4 CKD patients were randomized to receive standard nephrological care with (N = 72) or without (N = 64) a lifestyle and exercise intervention for 12 months. Plasma total F2-isoprostanes (IsoP), glutathione peroxidase (GPX) activity, total antioxidant capacity (TAC), anthropometric and biochemical data were collected at baseline and at 12 months. RESULTS: There were no significant differences between groups at baseline. There were no significant differences in changes for standard care and lifestyle intervention, respectively, in IsoP (p = 0.88), GPX (p = 0.87), or TAC (p = 0.56). Patients identified as having high IsoP at baseline (>250 pg/mL) had a greater decrease in IsoP with lifestyle intervention compared to standard care; however, the difference was not statistically significant (p = 0.06). There was no difference in the change in kidney function (eGFR) between standard care and lifestyle intervention (p = 0.33). DISCUSSION: Exercise and lifestyle modification in stage 3-4 CKD did not produce changes in systemic biomarkers of oxidative stress over a 12-month period, but patients with high IsoP may benefit most from the addition of intervention to standard care.

High-intensity interval training and cardiac autonomic control in individuals with metabolic syndrome: A randomised trial.

BACKGROUND: Insulin resistance has been postulated to play a central role in the co-appearance of various cardiovascular disease risk factors constituting the metabolic syndrome (MetS). There is evidence that altered cardiac autonomic function (CAF) may precede the onset of insulin resistance. Exercise training has been shown to improve CAF in different populations, yet little is known regarding the exercise dose response for CAF. The aim of this study was to investigate the impact of different volumes of high-intensity interval training (HIIT) and traditional moderate-intensity continuous training (MICT) on CAF in participants with MetS. METHODS: Individuals with MetS (n=56) were randomised into the following 16-week training interventions: i) MICT (n=16, 30min at 60-70%HRpeak, 5×/week); ii) 4HIIT (n=19, 4×4min bouts at 85-95%HRpeak, interspersed with 3min of active recovery at 50-70%HRpeak, 3×/week); or iii) 1HIIT (n=21, 1×4min bout at 85-95%HRpeak, 3×/week). R-R interval recorded for 5min in a supine position at pre- and post-intervention was used to derive linear (SDNN, RMSSD, pNN50, LF, HF, LF/HF) and non-linear (SD1, SD2, Alpha1, Alpha2, SampEn) heart rate variability (HRV) indices as measures of CAF. Group×time interaction effects were examined (ANCOVA) and Eta squared (η2) interaction effect sizes calculated. RESULTS: While there were no significant between-group differences in CAF indices, there were small-to-medium group×time interaction effects on SDNN [F(2,52)=0.70, p=0.50, η2=0.02], RMSSD [F(2,52)=1.35, p=0.27, η2=0.03], HF power [F(2,52)=1.27, p=0.29, η2=0.03], SD1 [F(2,52)=0.47, p=0.63, η2=0.01], and SD2 [F(2,52)=0.41, p=0.67, η2=0.01]. The following represent the relative percentage increases across these variables for 4HIIT, MICT, and 1HIIT respectively (SDNN, +30%, +17%, 9%; RMSSD, +30%, +22%, -2%; HF power, +69%, +18%, +7%; SD1, +30%, +22%,-2%; SD2, +22%, +14%, 4%). CONCLUSIONS: There were no significant between-group differences for the effects of exercise dose on CAF indices, however; high-volume HIIT demonstrated the greatest magnitude of effect for improving CAF in individuals with MetS.

Low-Volume High-Intensity Interval Training Is Sufficient to Ameliorate the Severity of Metabolic Syndrome.

BACKGROUND: High-intensity interval training (HIIT) is superior to moderate-intensity continuous training (MICT) at improving cardiometabolic risk. However, the optimal volume of HIIT to reduce the severity of the metabolic syndrome (MetS) has yet to be investigated. The aim of this study was to examine the impact of different volumes of HIIT and MICT on MetS severity (MetS z-score). METHODS: This was a substudy of the "Exercise in prevention of Metabolic Syndrome" (EX-MET) multicenter trial, reporting data collected at the Brisbane site. Ninety-nine adults diagnosed with MetS were randomized to one of the following 16-week interventions: (1) MICT [n = 34, 30 min at 60%-70% heart rate (HR) peak/session, 150 min/week]; (2) 4HIIT (n = 34, 4 × 4 min bouts at 85%-95% HR peak, interspersed with 3 min active recovery at 50%-70% HR peak, 114 min/week); or (3) 1HIIT (n = 31, 1 × 4 min bout at 85%-95% HR peak, 51 min/week). Z-scores were derived from levels of MetS risk factors before and after the intervention. RESULTS: Eighty-one participants completed post-testing (MICT, n = 26; 4HIIT, n = 28, 1HIIT, n = 27). After excluding 16 participants who had a change in medication dosage or type during the intervention, a total of 65 participants were included in the analysis [MICT, n = 22, age 55 ± 10 years, body mass index (BMI) 32 ± 6 kg/m; 4HIIT, n = 22, 56 ± 10 years, 35 ± 9 kg/m2; 1HIIT, n = 21, 57 ± 8 years, 32 ± 5 kg/m). MetS severity reduced following all interventions (pre- to post-MetS z-score: MICT, 1.80 ± 1.93 to 0.90 ± 1.93; 4HIIT, 2.75 ± 2.56 to 2.17 ± 2.71; 1HIIT, 2.48 ± 3.38 to 0.84 ± 2.98), with no significant differences between groups. There were no reported adverse events that were directly related to the exercise interventions. CONCLUSIONS: Low-volume HIIT (51 min/week) was as effective as high-volume HIIT (114 min/week) and MICT (150 min/week) in ameliorating MetS severity.