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Wrist-worn monitors claim to provide accurate measures of heart rate and energy expenditure. People wishing to lose weight use these devices to monitor energy balance, however the accuracy of these devices to measure such parameters has not been established. To determine the accuracy of four wrist-worn devices (Apple Watch, Fitbit Charge HR, Samsung Gear S and Mio Alpha) to measure heart rate and energy expenditure at rest and during exercise. Twenty-two healthy volunteers (50% female; aged 24 ± 5.6 years) completed ~1-hr protocols involving supine and seated rest, walking and running on a treadmill and cycling on an ergometer. Data from the devices collected during the protocol were compared with reference methods: electrocardiography (heart rate) and indirect calorimetry (energy expenditure). None of the devices performed significantly better overall, however heart rate was consistently more accurate than energy expenditure across all four devices. Correlations between the devices and reference methods were moderate to strong for heart rate (0.67-0.95 [0.35 to 0.98]) and weak to strong for energy expenditure (0.16-0.86 [-0.25 to 0.95]). All devices underestimated both outcomes compared to reference methods. The percentage error for heart rate was small across the devices (range: 1-9%) but greater for energy expenditure (9-43%). Similarly, limits of agreement were considerably narrower for heart rate (ranging from -27.3 to 13.1 bpm) than energy expenditure (ranging from -266.7 to 65.7 kcals) across devices. These devices accurately measure heart rate. However, estimates of energy expenditure are poor and would have implications for people using these devices for weight loss.

Background Vascular dysfunction is a precursor to the atherosclerotic cascade, significantly increasing susceptibility to cardiovascular events such as myocardial infarction or stroke. Previous studies have revealed a strong relationship between vascular function and cardiorespiratory fitness (CRF). Thus, since high-intensity interval training (HIIT) is a potent method of improving CRF, several small randomized trials have investigated the impact on vascular function of HIIT relative to moderate-intensity continuous training (MICT). Objective The aim of this study was to systematically review the evidence and quantify the impact on vascular function of HIIT compared with MICT. Methods Three electronic databases (PubMed, Embase, and MEDLINE) were searched (until May 2014) for randomized trials comparing the effect of at least 2 weeks of HIIT and MICT on vascular function. HIIT protocols involved predominantly aerobic exercise at a high intensity, interspersed with active or passive recovery periods. We performed a meta-analysis to compare the mean difference in the change in vascular function assessed via brachial artery flow-mediated dilation (FMD) from baseline to post-intervention between HIIT and MICT. The impact of HIIT versus MICT on CRF, traditional cardiovascular disease (CVD) risk factors, and biomarkers associated with vascular function (oxidative stress, inflammation, and insulin resistance) was also reviewed across included studies. Results Seven randomized trials, including 182 patients, met the eligibility criteria and were included in the meta-analysis. A commonly used HIIT prescription was four intervals of 4 min (4 × 4 HIIT) at 85–95 % of maximum or peak heart rate (HR max/peak ), interspersed with 3 min of active recovery at 60–70 % HR max/peak , three times per week for 12–16 weeks. Brachial artery FMD improved by 4.31 and 2.15 % following HIIT and MICT, respectively. This resulted in a significant ( p  < 0.05) mean difference of 2.26 %. HIIT also had a greater tendency than MICT to induce positive effects on secondary outcome measures, including CRF, traditional CVD risk factors, oxidative stress, inflammation, and insulin sensitivity. Conclusion HIIT is more effective at improving brachial artery vascular function than MICT, perhaps due to its tendency to positively influence CRF, traditional CVD risk factors, oxidative stress, inflammation, and insulin sensitivity. However, the variability in the secondary outcome measures, coupled with the small sample sizes in these studies, limits this finding. Nonetheless, this review suggests that 4 × 4 HIIT, three times per week for at least 12 weeks, is a powerful form of exercise to enhance vascular function.

PurposeTo determine whether stiffness of the patellar tendon and quadriceps muscles is altered immediately after and 48 h after a single bout of maximal eccentric exercise of the knee extensor muscles.MethodsThirteen healthy individuals [group mean (SD) age 22.4 (3.5) years; 7 female] performed a single bout of maximal eccentric exercise of the non-dominant knee extensors, using an isokinetic dynamometer. Shear-wave velocity (an index of tissue stiffness) was recorded from the patellar tendon, vastus medialis (VM), rectus femoris (RF) and vastus lateralis (VL), before, following (post0), and 48 h after (post48) exercise. To investigate features of exercise induced muscle damage, maximal voluntary isometric contraction (MVIC) and self-reported pain and stiffness (numerical rating scales 0 = no pain/stiffness to 100 = worst imaginable pain/stiffness) were measured before, post0, and post48 exercise. Serum creatine kinase (CK) was measured before and post48 exercise.ResultsCompared to preexercise, MVIC decreased and self-reported pain and stiffness increased at post0 and post48 and CK levels increased at post48 (all p < 0.01). Compared to preexercise, shear-wave velocity was greater at post0 for the patellar tendon [15.9 (24.6)%, p = 0.01] and RF [23.6 (16.7)%, p < 0.001], each returning to baseline by post48. No significant differences were observed for VL or VM post0 or post48 exercise.ConclusionMaximal eccentric exercise produced an immediate increase in the stiffness of the patellar tendon and RF, resolving by 48 h. As this change was not observed in VL and VM, future studies may explore heterogeneity within synergist muscles following eccentric exercise.

Historically, heat has been used in various clinical and sports rehabilitation settings to treat soft tissue injuries. More recently, interest has emerged in using heat to pre-condition muscle against injury. The aim of this narrative review was to collate information on different types of heat therapy, explain the physiological rationale for heat therapy, and to summarise and evaluate the effects of heat therapy before, during and after muscle injury, immobilisation and strength training. Studies on skeletal muscle cells demonstrate that heat attenuates cellular damage and protein degradation (following in vitro challenges/insults to the cells). Heat also increases the expression of heat shock proteins (HSPs) and upregulates the expression of genes involved in muscle growth and differentiation. In rats, applying heat before and after muscle injury or immobilisation typically reduces cellular damage and muscle atrophy, and promotes more rapid muscle growth/regeneration. In humans, some research has demonstrated benefits of microwave diathermy (and, to a lesser extent, hot water immersion) before exercise for restricting muscle soreness and restoring muscle function after exercise. By contrast, the benefits of applying heat to muscle after exercise are more variable. Animal studies reveal that applying heat during limb immobilisation attenuates muscle atrophy and oxidative stress. Heating muscle may also enhance the benefits of strength training for improving muscle mass in humans. Further research is needed to identify the most effective forms of heat therapy and to investigate the benefits of heat therapy for restricting muscle wasting in the elderly and those individuals recovering from serious injury or illness.

The recognition that food-derived nonnutrient molecules can modulate gene expression to influence intracellular molecular mechanisms has seen the emergence of the fields of nutrigenomics and nutrigenetics. The aim of this review is to describe the properties of nutrigenomic activators of transcription factor Nrf2 (nuclear factor erythroid 2-related factor 2), comparing the potential for sulforaphane and other phytochemicals to demonstrate clinical efficacy as complementary medicines. Broccoli-derived sulforaphane emerges as a phytochemical with this capability, with oral doses capable of favourably modifying genes associated with chemoprevention. Compared with widely used phytochemical-based supplements like curcumin, silymarin, and resveratrol, sulforaphane more potently activates Nrf2 to induce the expression of a battery of cytoprotective genes. By virtue of its lipophilic nature and low molecular weight, sulforaphane displays significantly higher bioavailability than the polyphenol-based dietary supplements that also activate Nrf2. Nrf2 activation induces cytoprotective genes such as those playing key roles in cellular defense mechanisms including redox status and detoxification. Both its high bioavailability and significant Nrf2 inducer capacity contribute to the therapeutic potential of sulforaphane-yielding supplements.

Background Cardiorespiratory fitness (VO 2max ) is an excellent predictor of chronic disease morbidity and mortality risk. Guidelines recommend individuals undertake exercise training to improve VO 2max for chronic disease reduction. However, there are large inter-individual differences between exercise training responses. This systematic review is aimed at identifying genetic variants that are associated with VO 2max trainability. Methods Peer-reviewed research papers published up until October 2016 from four databases were examined. Articles were included if they examined genetic variants, incorporated a supervised aerobic exercise intervention; and measured VO 2max /VO 2peak pre and post-intervention. Results Thirty-five articles describing 15 cohorts met the criteria for inclusion. The majority of studies used a cross-sectional retrospective design. Thirty-two studies researched candidate genes, two used Genome-Wide Association Studies (GWAS), and one examined mRNA gene expression data, in addition to a GWAS. Across these studies, 97 genes to predict VO 2max trainability were identified. Studies found phenotype to be dependent on several of these genotypes/variants, with higher responders to exercise training having more positive response alleles than lower responders (greater gene predictor score). Only 13 genetic variants were reproduced by more than two authors. Several other limitations were noted throughout these studies, including the robustness of significance for identified variants, small sample sizes, limited cohorts focused primarily on Caucasian populations, and minimal baseline data. These factors, along with differences in exercise training programs, diet and other environmental gene expression mediators, likely influence the ideal traits for VO 2max trainability. Conclusion Ninety-seven genes have been identified as possible predictors of VO 2max trainability. To verify the strength of these findings and to identify if there are more genetic variants and/or mediators, further tightly-controlled studies that measure a range of biomarkers across ethnicities are required.

Evidence for the benefits of regular exercise is irrefutable and increasing physical activity levels should be a major goal at all levels of health care. People with hypertension are less physically active than those without hypertension and there is strong evidence supporting the blood pressure–lowering ability of regular exercise, especially in hypertensive individuals. This narrative review discusses evidence relating to exercise and cardiovascular (CV) risk in people with hypertension. Comparisons between aerobic, dynamic resistance, and static resistance exercise have been made along with the merit of different exercise volumes. High-intensity interval training and isometric resistance training appear to have strong CV protective effects, but with limited data in hypertensive people, more work is needed in this area. Screening recommendations, exercise prescriptions, and special considerations are provided as a guide to decrease CV risk among hypertensive people who exercise or wish to begin. It is recommended that hypertensive individuals should aim to perform moderate intensity aerobic exercise activity for at least 30 minutes on most (preferably all) days of the week in addition to resistance exercises on 2–3 days/week. Professionals with expertise in exercise prescription may provide additional benefit to patients with high CV risk or in whom more intense exercise training is planned. Despite lay and media perceptions, CV events associated with exercise are rare and the benefits of regular exercise far outweigh the risks. In summary, current evidence supports the assertion of exercise being a cornerstone therapy in reducing CV risk and in the prevention, treatment, and control of hypertension.

ObjectiveTo investigate the effectiveness of videoconferencing exercise interventions for people with chronic diseases.DesignSystematic review incorporating meta-analysis.Data sourcesPubMed, Cinahl, MEDLINE, Web of Science, Embase and Scopus.Eligibility criteriaThe current literature was searched following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Trials analysing participants with chronic disease undergoing aerobic and/or resistance exercise training over videoconferencing, with exercise capacity and/or quality of life outcomes were included. Meta-analyses were conducted for between-group comparisons of exercise capacity and quality of life. Risk of bias was analysed using the Downs and Black quality checklist and the certainty of evidence with Grading of Recommendations, Assessment, Development and Evaluation (GRADE).ResultsThirty-two trials were included in this review, of which 12 were comparator trials. Small–moderate between-group (videoconferencing vs comparator) effects favouring videoconferencing were seen for studies using a non-exercising comparator for exercise capacity (standardised mean difference (SMD)=0.616, 95% CI 0.278 to 0.954; p=<0.001) and quality of life (SMD=0.400, 95% CI 0.099 to 0.701; p=0.009). Small effects favouring videoconferencing were observed for studies using an exercising comparator for quality of life (SMD=0.271, 95% CI 0.028 to 0.515; p=0.029) and exercise capacity (SMD=0.242, 95% CI 0.059 to 0.426; p=0.009). Moderate risk of bias was identified for included studies (16.3±3.6/28), with GRADE certainty ratings of ‘low’ (quality of life) and ‘moderate’ (exercise capacity). Session attendance was 70% and was reported in 23 trials. No serious adverse events relating to videoconferencing were found. Nine trials documented the total number of technical issues that occurred in 17% of the sessions. Positive satisfaction outcomes were associated with ease of access and usefulness of technology.ConclusionIn patients with chronic disease, videoconferencing exercise interventions appear to be feasible and effective for improving exercise capacity and quality of life. More robust methodology is needed in future studies to improve the certainty of the evidence.PROSPERO registration numberCRD42020191243.

High levels of reactive oxygen species (ROS) produced in skeletal muscle during exercise have been associated with muscle damage and impaired muscle function. Supporting endogenous defence systems with additional oral doses of antioxidants has received much attention as a noninvasive strategy to prevent or reduce oxidative stress, decrease muscle damage and improve exercise performance. Over 150 articles have been published on this topic, with almost all of these being small-scale, low-quality studies. The consistent finding is that antioxidant supplementation attenuates exercise-induced oxidative stress. However, any physiological implications of this have yet to be consistently demonstrated, with most studies reporting no effects on exercise- induced muscle damage and performance. Moreover, a growing body of evidence indicates detrimental effects of antioxidant supplementation on the health and performance benefits of exercise training. Indeed, although ROS are associated with harmful biological events, they are also essential to the development and optimal function of every cell. The aim of this review is to present and discuss 23 studies that have shown that antioxidant supplementation interferes with exercise training-induced adaptations. The main findings of these studies are that, in certain situations, loading the cell with high doses of antioxidants leads to a blunting of the positive effects of exercise training and interferes with important ROS-mediated physiological processes, such as vasodilation and insulin signalling. More research is needed to produce evidence-based guidelines regarding the use of antioxidant supplementation during exercise training. We recommend that an adequate intake of vitamins and minerals through a varied and balanced diet remains the best approach to maintain the optimal antioxidant status in exercising individuals.

Antioxidants have been used as therapies to decrease oxidative stress and improve CVD risk in hemodialysis (HD) patients. A systematic search of the Medline database (search date 30 April 2011) found 56 studies investigating the effects of antioxidant therapies on biomarkers of oxidative stress (53 studies) or clinical outcomes (3 studies). The majority were small trials using a nonrandomized open-label design with a single HD group (no HD controls). Alpha-tocopherol was the most investigated antioxidant, with 20/25 studies reporting that this vitamin decreased oxidative stress, and one clinical outcome trial in 196 patients finding that it protected against secondary CVD. Studies using vitamin C were more equivocal, with 4/11 showing decreased oxidative stress and one clinical outcome trial showing no effect on morbidity or mortality. N-acetylcysteine was the most efficacious agent, with 4/4 studies indicating a decrease in oxidative stress and one trial (n=134) showing reduced CVD events. Seven studies have used therapy containing a combination of antioxidants, with five of these reporting decreased oxidative stress. Most intervention studies in HD patients, such as statin therapy and increased dialysis dose, have failed to show improvement in CVD outcomes. Two intervention trials using different antioxidants have found CVD benefits, suggesting that this line of therapy is effective in this resistant population. These studies require validation in larger, adequately powered trials.