Provision of dietary education in UK-based cardiac rehabilitation: a cross-sectional survey conducted in conjunction with the British Association for Cardiovascular Prevention and Rehabilitation.

Dietary education is a core component of cardiac rehabilitation (CR). It is unknown how or what dietary education is delivered across the UK. We aimed to characterise practitioners who deliver dietary education in UK CR and determine the format and content of the education sessions. A fifty-four-item survey was approved by the British Association for Cardiovascular Prevention and Rehabilitation (BACPR) committee and circulated between July and October 2021 via two emails to the BACPR mailing list and on social media. Practitioners providing dietary education within CR programmes were eligible to respond. Survey questions encompassed: practitioner job title and qualifications, resources, and the format, content and individual tailoring of diet education. Forty-nine different centres responded. Nurses (65·1 %) and dietitians (55·3 %) frequently provided dietary education. Practitioners had no nutrition-related qualifications in 46·9 % of services. Most services used credible resources to support their education, and 24·5 % used BACPR core competencies. CR programmes were mostly community based (40·8 %), lasting 8 weeks (range: 2-25) and included two (range: 1-7) diet sessions. Dietary history was assessed at the start (79·6 %) and followed up (83·7 %) by most centres; barriers to completing assessment were insufficient time, staffing or other priorities. Services mainly focused on the Mediterranean diet while topics such as malnutrition and protein intake were lower priority topics. Service improvement should focus on increasing qualifications of practitioners, standardisation of dietary assessment and improvement in protein and malnutrition screening and assessment.

Comparison of telehealth and supervised phase III cardiac rehabilitation in regional Australia: protocol for a non-inferiority trial.

INTRODUCTION: Exercise-based cardiac rehabilitation programmes (ExCRP) promote recovery and secondary prevention for individuals with cardiovascular disease (CVD). Despite this, enrolment and adherence to ExCRP in rural locations is low. Telehealth programmes provide a convenient, home-based intervention, but concerns remain about compliance to exercise prescription. This paper presents the rationale and protocol design to determine if telehealth delivered ExCRP is not inferior to supervised ExCRP for improving cardiovascular function and exercise fidelity. METHOD AND ANALYSIS: A non-inferiority, parallel (1:1), single-blinded randomised clinical trial will be conducted. Fifty patients with CVD will be recruited from a rural phase II ExCRP. Participants will be randomly assigned to telehealth or supervised ExCRP and prescribed three weekly exercise sessions for 6 weeks. Exercise sessions will include a 10 min warm up, up to 30 min of continuous aerobic exercise at a workload equivalent to the ventilatory anaerobic threshold and a 10 min cool down. The primary outcome will be change in cardiorespiratory fitness as measured by cardiopulmonary exercise test. Secondary outcome measures will include change in blood lipid profile, heart rate variability, pulse wave velocity, actigraphy measured sleep quality and training fidelity. Non-inferiority will be confirmed if intention-to-treat and per-protocol analyses conclude the same outcome following independent samples t-test with p<0.025. ETHICS AND DISSEMINATION: Research ethics committees at La Trobe University, St John of God Health Care and Bendigo Health approved the study protocol and informed consent. Findings will be published in peer-reviewed journals and disseminated among stakeholders. TRIAL REGISTRATION NUMBER: ACTRN12622000872730p; pre-results.

Serum transthyretin and aminotransferases are associated with lean mass in people with coronary heart disease: Further insights from the CARE-CR study.

Background: Low muscle mass disproportionately affects people with coronary heart disease compared to healthy controls but is under-researched and insufficiently treated. Inflammation, poor nutrition, and neural decline might contribute to low muscle mass. This study aimed to assess circulatory biomarkers related to these mechanisms [albumin, transthyretin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and C-terminal agrin fragment] and their relationship with muscle mass in people with coronary heart disease. Our findings could be beneficial to indicate mechanisms of sarcopenia, detect sarcopenia, and evaluate treatment. Methods: Serum blood samples from people with coronary heart disease were analysed for biomarker concentrations using enzyme-linked immunosorbent assays. Skeletal muscle mass was estimated using dual X-ray absorptiometry derived appendicular lean mass and reported as skeletal muscle index (SMI; kg m-2), and as a proportion of total body mass [appendicular skeletal mass (ASM%)]. Low muscle mass was defined as a SMI <7.0 and <6.0 kg m-2, or ASM% <25.72 and <19.43% for men and women, respectively. Associations between biomarkers and lean mass were adjusted for age and inflammation. Results: Sixty-four people were assessed; 14 (21.9%) had low muscle mass. People with low muscle mass had lower transthyretin (effect size 0.34, p = 0.007), ALT (effect size 0.34, p = 0.008), and AST (effect size 0.26, p = 0.037) concentrations, compared to those with normal muscle mass. SMI was associated with inflammation-corrected ALT (r = 0.261, p = 0.039) and with inflammation- and age-adjusted AST/ALT ratio (r = -0.257, p = 0.044). Albumin and C-terminal agrin fragment were not associated with muscle mass indices. Conclusion: Circulatory transthyretin, ALT and AST were associated with low muscle mass in people with coronary heart disease. Low concentrations of these biomarkers might indicate that low muscle mass is partially explained by poor nutrition and high inflammation in this cohort. Targeted treatments to address these factors could be considered for people with coronary heart disease.

The effectiveness of the Healthworks Staying Steady community-based falls prevention exercise programme to improve physical function in older adults: a 6-year service evaluation.

BACKGROUND: Falls prevention exercise programmes are evidence-based and recommended for improving physical function in older adults. However, few service evaluations exist to assess the effectiveness of community-delivered interventions in practice. METHODS: We conducted a six-year, retrospective evaluation of the community-delivered Staying Steady programme (Healthworks, United Kingdom). Staying Steady is a 27-week, tailored strength and balance programme delivered in a group setting (1-h, once/week) and at home (30-40 min, 2-3 times/week). Participants were referred by healthcare professionals, or self-referred, due to a history or risk of falling. Routinely collected outcome measures (30-s chair stand, Timed Up and Go, four-stage balance test, and patient reported outcomes; including 'fear of falling' and 'ability to manage health') were analysed. Factors associated with programme completion were reported. The intervention effect on physical function was analysed in subgroups: participants used arms to chair-stand or a walking-aid at both ('aided'), neither ('unaided'), or one assessment timepoint ('aided at baseline only' or 'aided at follow-up only'). RESULTS: There were 1,426 referrals; 835 (67.3%) participants enrolled on to the Staying Steady programme, 406 (32.7%) declined, 185 (13.0%) were inappropriately referred and excluded from analysis. After enrolling, 451 (54.0%) participants completed, and 384 (46.0%) dropped out. Chair stand performance improved in participants who were unaided (n = 264; median 2.0 [1.0, 4.0] repetitions; P < 0.001), or aided at baseline, follow-up or both (n = 170, P < 0.05). Timed Up and Go performance improved in the unaided (n = 387; median -3.1 [-5.4, -1.4] s, P < 0.001), and aided at baseline only (n = 32; median -4.9 [-10.8, -3.4] s, P < 0.001) groups. Four-stage balance performance improved (n = 295; median 1.0 [0.0, 1.0] points, P < 0.001). After programme completion, participants self-reported an improved ability to manage their health and daily activities, improved confidence, and a reduced fear of falling. Presence of chronic obstructive pulmonary disease, fear of falling, prescribed nutritional support, disability and social deprivation influenced non-completion of Staying Steady. CONCLUSIONS: Completing Staying Steady improved physical function in older adults. Methods to encourage retention of participants from groups associated with low uptake and adherence should be investigated.

Dietary Nitrate Supplementation Does Not Alter Exercise Efficiency at High Altitude - Further Results From the Xtreme Alps Study.

Introduction: Nitrate supplementation in the form of beetroot juice (BRJ) ingestion has been shown to improve exercise tolerance during acute hypoxia, but its effect on exercise physiology remains unstudied during sustained terrestrial high altitude exposure. We hypothesized that performing exercise at high altitude would lower circulating nitrate and nitrite levels and that BRJ ingestion would reverse this phenomenon while concomitantly improving key determinants of aerobic exercise performance. Methods: Twenty seven healthy volunteers (21 male) underwent a series of exercise tests at sea level (SL, London, 75 m) and again after 5-8 days at high altitude (HA, Capanna Regina Margherita or "Margherita Hut," 4,559 m). Using a double-blind protocol, participants were randomized to consume a beetroot/fruit juice beverage (three doses per day) with high levels of nitrate (∼0.18 mmol/kg/day) or a nitrate-depleted placebo (∼11.5 µmoles/kg/day) control drink, from 3 days prior to the exercise trials until completion. Submaximal constant work rate cycle tests were performed to determine exercise efficiency and a maximal incremental ramp exercise test was undertaken to measure aerobic capacity, using breath-by-breath pulmonary gas exchange measurements throughout. Concentrations of nitrate, nitrite and nitrosation products were quantified in plasma samples collected at 5 timepoints during the constant work rate tests. Linear mixed modeling was used to analyze data. Results: At both SL and HA, plasma nitrate concentrations were elevated in the nitrate supplementation group compared to placebo (P < 0.001) but did not change throughout increasing exercise work rate. Delta exercise efficiency was not altered by altitude exposure (P = 0.072) or nitrate supplementation (P = 0.836). V̇O2peak decreased by 24% at high altitude (P < 0.001) and was lower in the nitrate-supplemented group at both sea level and high altitude compared to placebo (P = 0.041). Dietary nitrate supplementation did not alter other peak exercise variables or oxygen consumption at anaerobic threshold. Circulating nitrite and S-nitrosothiol levels unexpectedly rose in a few individuals right after cessation of exercise at high altitude. Conclusion: Whilst regularly consumed during an 8 days expedition to terrestrial high altitude, nitrate supplementation did not alter exercise efficiency and other exercise physiological variables, except decreasing V̇O2peak. These results and those of others question the practical utility of BRJ consumption during prolonged altitude exposure.

How has technology been used to deliver cardiac rehabilitation during the COVID-19 pandemic? An international cross-sectional survey of healthcare professionals conducted by the BACPR.

OBJECTIVE: To investigate whether exercise-based cardiac rehabilitation services continued during the COVID-19 pandemic and how technology has been used to deliver home-based cardiac rehabilitation. DESIGN: A mixed methods survey including questions about exercise-based cardiac rehabilitation service provision, programme diversity, patient complexity, technology use, barriers to using technology, and safety. SETTING: International survey of exercise-based cardiac rehabilitation programmes. PARTICIPANTS: Healthcare professionals working in exercise-based cardiac rehabilitation programmes worldwide. MAIN OUTCOME MEASURES: The proportion of programmes that continued providing exercise-based cardiac rehabilitation and which technologies had been used to deliver home-based cardiac rehabilitation. RESULTS: Three hundred and thirty eligible responses were received; 89.7% were from the UK. Approximately half (49.3%) of respondents reported that cardiac rehabilitation programmes were suspended due to COVID-19. Of programmes that continued, 25.8% used technology before the COVID-19 pandemic. Programmes typically started using technology within 19 days of COVID-19 becoming a pandemic. 48.8% did not provide cardiac rehabilitation to high-risk patients, telephone was most commonly used to deliver cardiac rehabilitation, and some centres used sophisticated technology such as teleconferencing. CONCLUSIONS: The rapid adoption of technology into standard practice is promising and may improve access to, and participation in, exercise-based cardiac rehabilitation beyond COVID-19. However, the exclusion of certain patient groups and programme suspension could worsen clinical symptoms and well-being, and increase hospital admissions. Refinement of current practices, with a focus on improving inclusivity and addressing safety concerns around exercise support to high-risk patients, may be needed.

The influence of resistance training on neuromuscular function in middle-aged and older adults: A systematic review and meta-analysis of randomised controlled trials.

BACKGROUND: Deterioration of neuromuscular function is a major mechanism of age-related strength loss. Resistance training (RT) improves muscle strength and mass. However, the effects of RT on neuromuscular adaptations in middle-aged and older adults are unclear. METHODS: Randomised controlled RT interventions (≥2 weeks) involving adults aged ≥50 years were identified. Primary outcome measures were voluntary activation (VA), electromyographic (EMG) activity during maximal voluntary contraction (MVC), and antagonist coactivation. Data were pooled using a weighted random-effect model. Sub-analyses were conducted by muscle or muscle group and health status of participants. Sensitivity analysis was based on study quality. P < 0.05 indicated statistical significance. RESULTS: Twenty-seven studies were included. An effect was found for VA (standardised mean difference [SMD] 0.54, 0.01 to 1.07, P = 0.04), This result remained significant following sensitivity analysis involving only studies that were low risk of bias. Subgroup analyses showed an effect for plantar flexor VA (SMD 1.13, 0.20 to 2.06, P = 0.02) and VA in healthy participants (SMD 1.04, 0.32 to 1.76, P = 0.004). There was no effect for EMG activity or antagonist coactivation of any muscle group (P > 0.05). DISCUSSION: Resistance training did not alter EMG activity or antagonist coactivation in older adults. Sensitivity analysis resulted in the effect for VA remaining significant, indicating that this finding was not dependent on study quality. Studies predominantly involved healthy older adults (78%), limiting the generalisability of these findings to clinical cohorts. Future research should determine the effects of RT on neuromuscular function in people with sarcopenia and age-related syndromes.

The effect of acute exercise on environmentally induced symptoms of dry eye.

The purpose of this study was to investigate the effects of acute exercise on environmentally induced symptoms of dry eye. Twelve participants without dry eye disease volunteered to complete three experimental visits in a randomized order; (1) control condition seated for 1 h at a relative humidity (RH) of 40% (CONT), (2) dry condition seated for 1 h at a RH of 20% (DRY), and (3) exercise condition seated for 40 min followed by 20 min of cycling exercise at a RH of 20% (EXER). Tear volume, tear matrix metalloproteinase 9 (MMP-9), perception of dry eye symptoms (frequency and severity), core temperature, and ocular surface temperature (OST) were measured at the end of each exposure. The perception of dry eye frequency and MMP-9 concentration were significantly higher in DRY compared to CONT (P < 0.012), with no differences in EXER compared to CONT. The results suggest that an acute bout of exercise may attenuate symptoms of environmentally induced dry eye, and warrant further research.

Exercise-induced attenuation of treatment side-effects in patients with newly diagnosed prostate cancer beginning androgen-deprivation therapy: a randomised controlled trial.

OBJECTIVES: (i) To assess whether exercise training attenuates the adverse effects of treatment in patients with newly diagnosed prostate cancer beginning androgen-deprivation therapy (ADT), and (ii) to examine whether exercise-induced improvements are sustained after the withdrawal of supervised exercise. PATIENTS AND METHODS: In all, 50 patients with prostate cancer scheduled for ADT were randomised to an exercise group (n = 24) or a control group (n = 26). The exercise group completed 3 months of supervised aerobic and resistance exercise training (twice a week for 60 min), followed by 3 months of self-directed exercise. Outcomes were assessed at baseline, 3- and 6-months. The primary outcome was difference in fat mass at 3-months. Secondary outcomes included: fat-free mass, cardiopulmonary exercise testing variables, QRISK® 2 (ClinRisk Ltd, Leeds, UK) score, anthropometry, blood-borne biomarkers, fatigue, and quality of life (QoL). RESULTS: At 3-months, exercise training prevented adverse changes in peak O2 uptake (1.9 mL/kg/min, P = 0.038), ventilatory threshold (1.7 mL/kg/min, P = 0.013), O2 uptake efficiency slope (0.21, P = 0.005), and fatigue (between-group difference in Functional Assessment of Chronic Illness Therapy-Fatigue score of 4.5 points, P = 0.024) compared with controls. After the supervised exercise was withdrawn, the differences in cardiopulmonary fitness and fatigue were not sustained, but the exercise group showed significantly better QoL (Functional Assessment of Cancer Therapy-Prostate difference of 8.5 points, P = 0.034) and a reduced QRISK2 score (-2.9%, P = 0.041) compared to controls. CONCLUSION: A short-term programme of supervised exercise in patients with prostate cancer beginning ADT results in sustained improvements in QoL and cardiovascular events risk profile.

The effect of protein and essential amino acid supplementation on muscle strength and performance in patients with chronic heart failure: a systematic review.

PURPOSE: Critically low skeletal muscle mass and strength, observed in 20% of people with chronic heart failure (CHF), reduces functional capacity, quality of life (QoL) and survival. Protein and essential amino acid (EAA) supplementation could be a viable treatment strategy to prevent declines in muscle strength and performance, and subsequently improve QoL and survival. This systematic review (PROSPERO: CRD42018103649) aimed to assess the effect of dietary protein and/or EAA supplementation on muscle strength and performance in people with CHF. METHODS: Searches of PubMed, MEDLINE and Embase identified studies that reported changes in strength or muscle performance following protein and/or EAA supplementation in patients with CHF. Following PRISMA guidelines and using predefined inclusion/exclusion criteria relating to participants, intervention, control, outcome and study design, two reviewers independently screened titles, abstracts and full manuscripts for eligibility. Risk of bias was assessed using Cochrane Risk of Bias Tool (RCTs) or Mixed Methods Appraisal Tool (cohort studies). Data were extracted for analysis using predefined criteria. RESULTS: Five randomised controlled trials (RCT) and one cohort study met our inclusion criteria. All RCTs had a high risk of bias. The methodological quality of the cohort study was moderate. Heterogeneity of extracted data prevented meta-analyses, qualitative synthesis was therefore performed. Data from 167 patients with CHF suggest that protein and/or EAA supplementation does not improve strength, but may increase six-minute walk test distance, muscle mass and QoL. CONCLUSIONS: The limited quality of the studies makes firm conclusions difficult, however protein and/or EAA supplementation may improve important outcome measures related to sarcopenia. High-quality randomised controlled studies are needed.

Hemodynamic effects of portable non-invasive ventilation in healthy men.

VitaBreath is a portable, non-invasive ventilation device (pNIV) that relieves shortness of breath in COPD by delivering fixed inspiratory and expiratory positive airway pressures (IPAP/EPAP: 18/8 cmH2O). Fixed pressures may cause circulatory compromise. We investigated the circulatory effects of pNIV during normal breathing (NB) and after Eucapnic Voluntary Hyperpnoea trials (EVH) sustained at 80% MVV. In a balanced order sequence, 10 healthy men performed four trials on one visit: 1-min of pNIV (intervention) or 1-min quiet breathing (QB) during NB; and 1-min pNIV (intervention) or 1-min QB during recovery from 3-min EVH. Compared to QB, pNIV application was associated with greater cardiac output (CO: 1.6 ± 1.9 L.min-1; P = 0.03). One minute into recovery from EVH, pNIV caused greater CO (2.2 ± 1.6 L.min-1; P = 0.01) compared to QB. Mean blood pressure was not different with pNIV compared to control. pNIV increased thoracoabdominal volumes and breathing frequency during NB and recovery from EVH. pNIV application does not induce adverse hemodynamic effects in healthy men.

Low skeletal muscle mass is associated with low aerobic capacity and increased mortality risk in patients with coronary heart disease - a CARE CR study.

BACKGROUND: In patients with chronic heart failure, there is a positive linear relationship between skeletal muscle mass (SMM) and peak oxygen consumption ( V ˙ O2peak ); an independent predictor of all-cause mortality. We investigated the association between SMM and V ˙ O2peak in patients with coronary heart disease (CHD) without a diagnosis of heart failure. METHODS: Male patients with CHD underwent maximal cardiopulmonary exercise testing and dual X-ray absorptiometry assessment. V ˙ O2peak, the ventilatory anaerobic threshold and peak oxygen pulse were calculated. SMM was expressed as appendicular lean mass (lean mass in both arms and legs) and reported as skeletal muscle index (SMI; kg m-2 ), and as a proportion of total body mass (appendicular skeletal mass [ASM%]). Low SMM was defined as a SMI <7·26 kg m-2 , or ASM% <25·72%. Five-year all-cause mortality risk was calculated using the Calibre 5-year all-cause mortality risk score. RESULTS: Sixty patients were assessed. Thirteen (21·7%) had low SMM. SMI and ASM% correlated positively with V ˙ O2peak (r = 0·431 and 0·473, respectively; P<0·001 for both). SMI and ASM% predicted 16·3% and 12·9% of the variance in V ˙ O2peak , respectively. SMI correlated most closely with peak oxygen pulse (r = 0·58; P<0·001). SMI predicted 40·3% of peak V ˙ O2 /HR variance. ASM% was inversely associated with 5-year all-cause mortality risk (r = -0·365; P = 0·006). CONCLUSION: Skeletal muscle mass was positively correlated with V ˙ O2peak in patients with CHD. Peak oxygen pulse had the strongest association with SMM. Low ASM% was associated with a higher risk of all-cause mortality. The effects of exercise and nutritional strategies aimed at improving SMM and function in CHD patients should be investigated.

The Effects of Acute Interval Exercise and Strawberry Intake on Postprandial Lipemia.

PURPOSE: Raised postprandial triglycerides (TAG) and related oxidative stresses are strongly associated with increased cardiovascular disease risk. Acute exercise and strawberry ingestion independently ameliorate postprandial lipid excursions and oxidative stress. However, the combined effects of these lifestyle interventions are unknown. We investigated whether acute exercise and strawberry consumption improved postprandial responses to an oral fat tolerance test (OFTT) in overweight/obese males. METHODS: Overweight/obese adult males underwent four separate OFTT (73 g fat, 33 g carbohydrate) with blood sampled at baseline and hourly for 4 h after OFTT. Two OFTT contained 25 g freeze-dried strawberries and two contained strawberry flavoring (placebo). Participants performed 40 min of submaximal high-intensity interval cycling exercise 16 h before one strawberry and one placebo OFTT and rested before the remaining two OFTT. Serum TAG was analyzed, and TAG area under the curve (AUC) and incremental AUC (iAUC) were calculated. Oxidative stress markers were measured at baseline and 4 h. Differences between conditions (strawberry/placebo and exercise/rest) were assessed using repeated-measures ANOVA. RESULTS: Ten males (age = 31.5, interquartile range = 17.8 yr, body mass index = 29.9 ± 1.8 kg·m) completed the study. TAG AUC was 1.5 mmol per 4 h·L lower for the exercise conditions compared with the rest conditions (95% confidence interval [CI] = -2.3 to -0.8 mmol per 4 h·L, P = 0.001). TAG AUC was not different between strawberry and placebo conditions (95% CI = -1.3 to 0.6 mmol per 4 h·L, P = 0.475). TAG iAUC was 0.5 mmol per 4 h·L greater for the strawberry compared with the placebo conditions (95% CI = 0.1 to 1.0 mmol per 4 h·L, P = 0.021). There were no changes in markers of lipid related oxidative stress (P > 0.05). CONCLUSION: Acute submaximal high-intensity interval cycling exercise appears effective in reducing postprandial lipemia in overweight/obese adult males. However, strawberry ingestion did not improve postprandial TAG.

Validity and Reliability of the Apple Watch for Measuring Heart Rate During Exercise.

We examined the validity and reliability of the Apple Watch heart rate sensor during and in recovery from exercise. Twenty-one males completed treadmill exercise while wearing two Apple Watches (left and right wrists) and a Polar S810i monitor (criterion). Exercise involved 5-min bouts of walking, jogging, and running at speeds of 4 km.h -1 , 7 km.h -1 , and 10 km.h -1 , followed by 11 min of rest between bouts. At all exercise intensities the mean bias was trivial. There were very good correlations with the criterion during walking (L: r=0.97; R: r=0.97), but good (L: r=0.93; R: r=0.92) and poor/good (L: r=0.81; R: r=0.86) correlations during jogging and running. Standardised typical error of the estimate was small, moderate, and moderate to large. There were good correlations following walking, but poor correlations following jogging and running. The percentage of heart rates recorded reduced with increasing intensity but increased over time. Intra-device standardised typical errors decreased with intensity. Inter-device standardised typical errors were small to moderate with very good to nearly perfect intraclass correlations. The Apple Watch heart rate sensor has very good validity during walking but validity decreases with increasing intensity.

Genetic factors associated with exercise performance in atmospheric hypoxia.

BACKGROUND AND OBJECTIVE: 'Natural selection' has been shown to have enriched the genomes of high-altitude native populations with genetic variants of advantage in this hostile hypoxic environment. In lowlanders who ascend to altitude, genetic factors may also contribute to the substantial interindividual variation in exercise performance noted at altitude. We performed a systematic literature review to identify genetic variants of possible influence on human hypoxic exercise performance, commenting on the strength of any identified associations. CRITERIA FOR CONSIDERING STUDIES FOR THIS REVIEW: All studies of the association of genetic factors with human hypoxic exercise performance, whether at sea level using 'nitrogen dilution of oxygen' (normobaric hypoxia), or at altitude or in low-pressure chambers (field or chamber hypobaric hypoxia, respectively) were sought for review. SEARCH STRATEGY FOR IDENTIFICATION OF STUDIES: Two electronic databases were searched (Ovid MEDLINE, Embase) up to 31 January 2014. We also searched the reference lists of relevant articles for eligible studies. All studies published in English were included, as were studies in any language for which the abstract was available in English. DATA COLLECTION AND ANALYSIS: Studies were selected and data extracted independently by two reviewers. Differences regarding study inclusion were resolved through discussion. The quality of each study was assessed using a scoring system based on published guidelines for conducting and reporting genetic association studies. RESULTS: A total of 11 studies met all inclusion criteria and were included in the review. Subject numbers ranged from 20 to 1,931 and consisted of healthy individuals in all cases. The maximum altitude of exposure ranged from 2,690 to 8,848 m. The exercise performance phenotypes assessed were mountaineering performance (n = 5), running performance (n = 2), and maximum oxygen consumption ([Formula: see text]O2max) (n = 4). In total, 13 genetic polymorphisms were studied, four of which were associated with hypoxic exercise performance. The adenosine monophosphate deaminase (AMPD1) C34T (rs17602729), beta2-adrenergic receptor (ADRB2) Gly16Arg single nucleotide polymorphism (SNP) (rs1042713), and androgen receptor CAG repeat polymorphisms were associated with altitude performance in one study, and the angiotensin I-converting enzyme (ACE) insertion/deletion (I/D) (rs4646994) polymorphism was associated with performance in three studies. The median score achieved in the study quality analysis was 6 out of 10 for case-control studies, 8 out of 10 for cohort studies with a discrete outcome, 6 out of 9 for cohort studies with a continuous outcome, and 4.5 out of 8 for genetic admixture studies. CONCLUSION: The small number of articles identified in the current review and the limited number of polymorphisms studied in total highlights that the influence of genetic factors on exercise performance in hypoxia has not been studied in depth, which precludes firm conclusions being drawn. Support for the association between the ACE-I allele and improved high-altitude performance was the strongest, with three studies identifying a relationship. Analysis of study quality highlights the need for future studies in this field to improve the conduct and reporting of genetic association studies.

Association between preoperative haemoglobin concentration and cardiopulmonary exercise variables: a multicentre study.

BACKGROUND: Preoperative anaemia and low exertional oxygen uptake are both associated with greater postoperative morbidity and mortality. This study reports the association among haemoglobin concentration ([Hb]), peak oxygen uptake (V˙O2 peak) and anaerobic threshold (AT) in elective surgical patients. METHODS: Between 1999 and 2011, preoperative [Hb] and cardiopulmonary exercise tests were recorded in 1,777 preoperative patients in four hospitals. The associations between [Hb], V˙O2 peak and AT were analysed by linear regression and covariance. RESULTS: In 436 (24.5%) patients, [Hb] was <12 g dl-1 and, in 83 of these, <10 g dl-1. Both AT and V˙O2 peak rose modestly with increasing [Hb] (r2 = 0.24, P <0.0001 and r2 = 0.30, P <0.0001, respectively). After covariate adjustment, an increase in [Hb] of one standard deviation was associated with a 6.7 to 9.7% increase in V˙O2 peak, and a rise of 4.4 to 6.0% in AT. Haemoglobin concentration accounted for 9% and 6% of the variation in V˙O2 peak and AT respectively. CONCLUSIONS: To a modest extent, lower haemoglobin concentrations are independently associated with lower oxygen uptake during preoperative cardiopulmonary exercise testing. It is unknown whether this association is causative.