Australian cardiac rehabilitation exercise parameter characteristics and perceptions of high-intensity interval training: a cross-sectional survey

Purpose: This study explored current demographics, characteristics, costs, evaluation methods, and outcome measures used in Australian cardiac rehabilitation (CR) programs. It also determined the actual usage and perceptions of high-intensity interval training (HIIT). Methods: A cross-sectional observational web-based survey was distributed to 328 Australian CR programs nationally. Results: A total of 261 programs completed the survey (79.6% response rate). Most Australian CR programs were located in a hospital setting (76%), offered exercise sessions once a week (52%) for 6–8 weeks (49%) at moderate intensity (54%) for 46–60 min (62%), and serviced 101–500 clients per annum (38%). HIIT was reported in only 1% of programs, and 27% of respondents believed that it was safe while 42% of respondents were unsure. Lack of staff (25%), monitoring resources (20%), and staff knowledge (18%) were the most commonly reported barriers to the implementation of HIIT. Overall, Australian CR coordinators are unsure of the cost of exercise sessions. Conclusion: There is variability in CR delivery across Australia. Only half of programs reassess outcome measures postintervention, and cost of exercise sessions is unknown. Although HIIT is recommended in international CR guidelines, it is essentially not being used in Australia and clinicians are unsure as to the safety of HIIT. Lack of resources and staff knowledge were perceived as the biggest barriers to HIIT implementation, and there are inconsistent perceptions of prescreening and monitoring requirements. This study highlights the need to educate health professionals about the benefits and safety of HIIT to improve its usage and patient outcomes

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)

High-intensity interval training versus moderate-intensity continuous training within cardiac rehabilitation:a systematic review and meta-analysis

Aerobic capacity has been shown to be inversely proportionate to cardiovascular mortality and morbidity and there is growing evidence that high-intensity interval training (HIIT) appears to be more effective than moderate-intensity continuous training (MICT) in improving cardiorespiratory fitness within the cardiac population. Previously published systematic reviews in cardiovascular disease have neither investigated the effect that the number of weeks of intervention has on cardiorespiratory fitness changes, nor have adverse events been collated.We aimed to undertake a systematic review and meta-analysis of randomized controlled trials (RCTs) within the cardiac population that investigated cardiorespiratory fitness changes resulting from HIIT versus MICT and to collate adverse events.A critical narrative synthesis and meta-analysis was conducted after systematically searching relevant databases up to July 2017. We searched for RCTs that compared cardiorespiratory fitness changes resulting from HIIT versus MICT interventions within the cardiac population.Seventeen studies, involving 953 participants (465 for HIIT and 488 for MICT) were included in the analysis. HIIT was significantly superior to MICT in improving cardiorespiratory fitness overall (SMD 0.34 mL/kg/min; 95% confidence interval [CI; 0.2-0.48]; p6-week duration. Programs of 7-12 weeks' duration resulted in the largest improvements in cardiorespiratory fitness for patients with coronary artery disease. HIIT appears to be as safe as MICT for CR participants

Bismuth-coated mesoporous platinum microelectrodes as sensors for formic acid detection

Mesoporous platinum microeletrodes (MPtEs) modified by sub-monolayers of irreversibly adsorbed bismuth (Bi-MPtE) were investigated for their potential use as sensors for the detection of formic acid in direct formic acid fuel cells. The mesoporous platinum films were prepared by electrodeposition of platinum on Pt microdisks substrates 25 m diameter, from hexachloroplatinic acid dissolved in the aqueous domain of the lyotropic liquid crystalline phase of octaethylene glycol monohexadecyl ether. The roughness factor (RF) of the MPtEs was about two orders of magnitude greater than those of the corresponding polished microelectrodes. Bismuth ad-atoms onto the platinum surface were deposited by under potential deposition from 1 mM Bi3+ ions in 0.5 M H2SO4 solutions. The catalytic activity of a series of Bi-MPtEs, characterized by different roughness and fractional bismuth coverage (Bi), towards the oxidation of HCOOH, was investigated by cyclic voltammetry and potential step experiments. Compared to MPtEs, Bi-MPtEs displayed enhanced electrooxidation currents at lower potentials. The stability of irreversibly adsorbed bismuth, and consequently the Bi-MPtEs catalytic activity, was found to depend on the high potential limit employed in the measurements. In general, both electrode stability and electrocatalytic performance were good, provided that the operational potential was kept  0.4 V vs. Ag/AgCl. Bi-MPtEs with Bi > 0.3 provided almost sigmoidal shaped waves with low hysteresis, as those expected for microelectrodes working under steady state. The effect of concentration of HCOOH was investigated over the range 0.01 – 5 M, and linearity between current and concentration depended on both roughness factor and bismuth coverage. A Bi-MPtE characterised by RF = 210 and Bi ≥ 0.6 provided linearity up to 2 M of formic acid. Reproducibility of the sensors was within 2% (r.s.d). The same sensor, under the optimized experimental conditions, could be employed for at least two months with negligible loss of the initial performance

Time course and dose response of alpha tocopherol on oxidative stress in haemodialysis patients

Background: Oxidative stress is associated with increased cardiovascular morbidity and mortality particularly in patients with end stage kidney disease. Although observational data from the general population has shown dietary antioxidant intake is associated with reduced cardiovascular morbidity and mortality, most clinical intervention trials have failed to support this relationship. This may be a consequence of not using an effective antioxidant dose and/or not investigating patients with elevated oxidative stress. The SPACE study, conducted in haemodialysis patients, reported that 800 IU/day of alpha tocopherol significantly reduced cardiovascular disease endpoints. A recent time course and dose response study conducted in hypercholesterolaemic patients that found 1600 IU/day of alpha tocopherol was an optimal dose. There is no such dose response data available for haemodialysis patients. Therefore the aim of this study is to investigate the effect of different doses of oral alpha tocopherol on oxidative stress in haemodialysis patients with elevated oxidative stress and the time taken to achieve this effect

The effect of dietary sodium modification on blood pressure in adults with systolic blood pressure less than 140 mmHg: A systematic review

TYPES OF INTERVENTIONS: Interventions that quantitatively evaluated dietary sodium intake for equal to or greater than four weeks duration were considered. Only studies that included two study arms comprising different levels of sodium intake were included

a-Tocopherol and a-Lipoic Acid Enhance the Erythrocyte Antioxidant Defence in Cyclosporine A-Treated Rats

Abstract: The aim of this study was to determine the effects of dietary antioxidant supplementation with a-tocopherol and a-lipoic acid on cyclosporine A (cyclosporine)-induced alterations to erythrocyte and plasma redox balance. Rats were randomly assigned to either control, antioxidant (a-tocopherol 1000 IU/kg diet and a-lipoic acid 1.6 g/kg diet), cyclosporine (25 mg/kg/day), or cyclosporine π antioxidant treatments. Cyclosporine was administered for 7 days after an 8 week feeding period. Plasma was analysed for a-tocopherol, total antioxidant capacity, malondialdehyde, and creatinine. Erythrocytes were analysed for glutathione, methaemoglobin, superoxide dismutase, catalase, glutathione peroxidase, glucose-6-phosphate dehydrogenase, a-tocopherol and malondialdehye. Cyclosporine administration caused a significant decrease in superoxide dismutase activity (PϽ0.05 control versus cyclosporine) and this was improved by antioxidant supplementation (PϽ0.05 cyclosporine versus cyclosporine π antioxidant; PϽ0.05 control versus cyclosporine π antioxidant). Animals receiving cyclosporine and antioxidants showed significantly increased (PϽ0.05) catalase activity compared to both groups not receiving cyclosporine. Cyclosporine administration induced significant increases in plasma malondialdehyde and creatinine concentration (PϽ0.05 control versus cyclosporine). Antioxidant supplementation prevented the cyclosporine induced increase in plasma creatinine (PϽ0.05 cyclosporine versus cyclosporine π antioxidant; PϾ0.05 control versus cyclosporine π antioxidant), however, supplementation did not alter the cyclosporine induced increase in plasma malondialdehyde concentration (PϾ0.05 cyclosporine versus cyclosporine π antioxidant). Antioxidant supplementation resulted in significant increases (PϽ0.05) in plasma and erythrocyte a-tocopherol in both of the supplemented groups compared to non-supplemented groups. In conclusion, dietary supplementation with a-tocopherol and a-lipoic acid enhanced the erythrocyte antioxidant defence and reduced nephrotoxicity in cyclosporine treated animals

Where Does Blood Flow Restriction Fit in the Toolbox of Athletic Development? A Narrative Review of the Proposed Mechanisms and Potential Applications

Blood flow-restricted exercise is currently used as a low-intensity time-efficient approach to reap many of the benefits of typical high-intensity training. Evidence continues to lend support to the notion that even highly trained individuals, such as athletes, still benefit from this mode of training. Both resistance and endurance exercise may be combined with blood flow restriction to provide a spectrum of adaptations in skeletal muscle, spanning from myofibrillar to mitochondrial adjustments. Such diverse adaptations would benefit both muscular strength and endurance qualities concurrently, which are demanded in athletic performance, most notably in team sports. Moreover, recent work indicates that when traditional high-load resistance training is supplemented with low-load, blood flow-restricted exercise, either in the same session or as a separate training block in a periodised programme, a synergistic and complementary effect on training adaptations may occur. Transient reductions in mechanical loading of tissues afforded by low-load, blood flow-restricted exercise may also serve a purpose during de-loading, tapering or rehabilitation of musculoskeletal injury. This narrative review aims to expand on the current scientific and practical understanding of how blood flow restriction methods may be applied by coaches and practitioners to enhance current athletic development models.publishedVersionPaid open acces

Effect of personal activity intelligence (PAI) monitoring in the maintenance phase of cardiac rehabilitation: a mixed methods evaluation

Abstract Background Personal activity intelligence (PAI) is a single physical activity metric based upon heart rate responses to physical activity. Maintaining 100 PAI/week is associated with a 25% risk reduction in cardiovascular disease mortality and 50 PAI/week provides 60% of the benefits. The effect of utilising this metric within a cardiac population has not been previously investigated. The aim of this study was to determine the effect of PAI monitoring on the amount and/or intensity of physical activity for people in the maintenance phase of cardiac rehabilitation and to explore participants’ perceptions of this approach. Methods A concurrent mixed methods approach was undertaken. Participants in the maintenance phase of cardiac rehabilitation monitored PAI for six weeks via a wearable physical activity monitoring device (WPAM). In the first three weeks participants were blinded to their PAI score. A quality-of-life questionnaire (EQ-5D-5L) was completed, and semi-structured interviews conducted to investigate attitudes to PAI monitoring. Daily PAI data was collected throughout the 6-week period. Results Twenty participants completed the trial. PAI earned/day was increased after participants could view their data (mean difference: 2.1 PAI/day (95% CI 0.3, 4.0), p = 0.027). The median change in percentage of days participants achieved a Total PAI score of 25 (p = 0.023) and 50 (p = 0.015) were also increased. The mean change in total scores for the EQ-5D-5L and EQVAS were improved after 6 weeks (0.6 ± 1.05; 95% CI (0.11–1.09); p = 0.019); (5.8/100; 95% CI (2.4–9.2); p = 0.002 respectively). Thematic framework analysis identified three global themes (perceptions on the WPAM, PAI and factors affecting exercise). Most participants stated motivation to exercise increased after they could view their PAI data. Many of the participants believed they would continue to use PAI long-term. Others were undecided; the latter primarily due to technical issues and/or preferring devices with greater functionality and attractiveness. All participants would recommend PAI. Conclusion This exploratory study showed monitoring PAI via a WPAM increased the amount and/or intensity of physical activity within the cardiac population. Participants found PAI interesting, beneficial, and motivating. If technical issues, aesthetics, and functionality of the WPAM were improved, participants may continue to use the approach long-term. PAI may be a viable strategy to assist people with cardiac disease maintain physical activity adherence

Relationship between homocysteine and cardiorespiratory fitness is sex-dependent

Abstract Elevated plasma homocysteine is recognized as an independent risk factor for cardiovascular disease. Recently, there have been conflicting reports of the relationship between physical activity and homocysteine. A more objective measure of physical activity is cardiorespiratory fitness; however, its relationship with homocysteine has yet to be investigated. The aim of this study was to determine the relationship between cardiorespiratory fitness and plasma homocysteine. Cross-sectional associations between cardiorespiratory fitness (VO 2 max) and plasma homocysteine were examined in 49 men and 11 women. A submaximal bicycle test was used to determine VO 2 max and plasma homocysteine was measured using high performance liquid chromatography with fluorescence detection. Dietary analysis determined B vitamin intake. There was a significant inverse relationship between plasma homocysteine concentration and VO 2 max in women (r ϭ Ϫ0.81, P ϭ 0.003) but not in men (r ϭ Ϫ0.09, P ϭ 0.95). There were no significant relationships between plasma homocysteine and age, BMI, body fat, total cholesterol, and LDL cholesterol. In summary, elevated cardiorespiratory fitness is associated with decreased plasma homocysteine concentrations in women