Search

SuperWASP is one of the largest ground-based surveys for transiting exoplanets. To date, it has observed over 31 million stars. Such an extensive database of time resolved photometry holds the potential for extensive searches of stellar variability, and provide solid candidates for the upcoming TESS mission. Previous work by e.g. [15], [5], [12] has shown that the WASP archive provides a wealth of pulsationally variable stars. In this talk I will provide an overview of the SuperWASP project, present some of the published results from the survey, and some of the on-going work to identify key targets for the TESS mission. more...

We present an analysis of the first K2 observations of a rapidly oscillating Ap (roAp) star, HD 24355. The star was discovered to be a roAp star by [1], with a frequency of 224.31 d-1 (2596.18 μHz; P = 6.4 min) and an amplitude of 1.51 mmag in SuperWASP broadband photometry. Spectroscopic analysis of low-resolution spectra show the star to be an A5 Vp SrEu star. The high precision K2 data allow us to identify 13 rotationally split sidelobes to the main pulsation frequency. This is the largest number of sidelobes seen in a roAp star to date. We also see an unusual pulsational phase variation as the star rotates, showing this star to be the most distorted quadrupole roAp pulsator yet observed. Modelling of this star confirms its quadrupole nature, and allows us to constrain the magnetic field strength, angle of inclination and the angle of obliquity. more...

The results of a search for amplitude modulation of pulsation modes in 983 δ Sct stars, which have effective temperatures between 6400 ⩽ Teff ⩽ 10 000 K in the Kepler Input Catalogue and were continuously observed by the Kepler Space Telescope for 4 yr, are presented. A total of 603 δ Sct stars (61.3 per cent) are found to exhibit at least one pulsation mode that varies significantly in amplitude over 4 yr. Furthermore, it is found that amplitude modulation is not restricted to a specific region within the classical instability strip in the HR diagram, therefore its cause is not necessarily dependent on stellar parameters such as Teff or log g. On the other hand, many δ Sct stars show constant pulsation amplitudes demonstrating that the cause of pulsational non-linearity in these stars is not well understood. more...

High cardiac sympathetic drive and release of the sympathetic cotransmitter neuropeptide Y (NPY) are significant features of congestive heart failure (CHF), in which resting venous NPY levels are known to be associated with mortality. However, whether circulating NPY levels increase during exercise in CHF when they are already elevated is controversial. We sought to establish the dynamics of circulating NPY levels in CHF patients treated with contemporary medical therapy and devices in relationship to indices of performance linked to long-term prognosis. CHF patients (n = 15) underwent cardiopulmonary exercise testing with venous blood sampling at rest, peak exercise and recovery. These patients had significantly higher resting venous NPY levels compared with an age- and sex-matched control group of patients (n = 16) with normal left ventricular function (40 ± 6.9 vs. 9.0 ± 4.6 pg/mL, respectively; P < 0.0001). In CHF patients, NPY levels increased significantly from baseline to peak exercise (to 93.5 ± 42.1 pg/mL; P = 0.0004) and remained elevated during recovery (86.8 ± 44.6 pg/mL; P = 0.0018). The peak (r = 0.58, P = 0.0222) and recovery (r = 0.56, P = 0.0304) NPY levels and the ability to increase NPY from baseline (r = 0.53, P = 0.0427) showed significant positive correlations with heart rate recovery at 1 min, but not with peak oxygen consumption. In CHF patients, the ability to increase NPY levels on exertion is correlated with heart rate recovery, a known prognostic indicator for mortality. These findings suggest that NPY dynamics during exercise might provide valuable insights into sympathetic responses and prognosis in CHF patients., (© 2024 The Author(s). Experimental Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.) more...

Background: Clinical guidelines do not recommend coronary computed tomographic angiography (CTA) in elderly patients or in the presence of heavy coronary calcification. Photon-counting coronary computed tomographic angiography (PCCTA) introduces ultrahigh in-plane resolution and multienergy imaging, but the ability of this technology to overcome these limitations is unclear., Objectives: The authors evaluate the ability of PCCTA to quantitatively assess coronary luminal stenosis in the presence and absence of calcification, comparing both the ultrahigh-resolution (UHR)-PCCTA and the multienergy standard-resolution (SR)-PCCTA with the criterion-standard 3-dimensional invasive quantitative coronary angiography (3D QCA)., Methods: The authors included 100 patients who had both PCCTA and invasive coronary angiography (ICA). They comparatively evaluated luminal diameter stenosis with PCCTA and 3D QCA, anatomic disease severity (according to CAD-RADS [Coronary Artery Disease-Reporting and Data System]) and the diagnostic performance of PCCTA in identifying coronary arteries with ≥50% diameter stenosis on 3D QCA requiring invasive hemodynamic severity evaluation and/or revascularization., Results: The authors analyzed 257 vessels and 343 plaques. UHR-PCCTA luminal evaluation relative to 3D QCA was more precise than SR-PCCTA (median difference: 3% [Q1-Q3: 1%-6%] vs 6% [Q1-Q3: 2%-11%]; P < 0.001), particularly in severely calcified arteries (median difference 3% [Q1-Q3: 1%-6%] vs 6% [Q1-Q3: 3%-13%]; P = 0.002). Per-vessel agreement for CAD-RADS between UHR-PCCTA and 3D QCA was near-perfect (κ = 0.90 [Q1-Q3: 0.84-0.95]; P < 0.001), and it was substantial for SR-PCCTA (κ = 0.63 [Q1-Q3: 0.54-0.71]; P < 0.001), especially in severely calcified arteries: κ = 0.90 (Q1-Q3: 0.83-0.97; P < 0.001) and κ = 0.67 (Q1-Q3: 0.56-0.77; P < 0.001), respectively. Per-vessel diagnostic performance of SR- and UHR-PCCTA was excellent: AUC: 0.94 (95% CI: 0.91-0.98; P < 0.001) and 0.99 (95% CI: 0.98-1.00; P < 0.001), respectively. UHR-PCCTA diagnostically outperformed SR-PCCTA: ΔAUC: 0.05 (95% CI: 0.01-0.08; P = 0.01)., Conclusions: PCCTA compares favorably with ICA for lumen assessment and anatomic disease severity classification in patients presenting with acute coronary syndrome or patients referred for ICA. UHR-PCCTA luminal evaluation is superior to SR-PCCTA, especially in patients with heavy coronary calcification. UHR-PCCTA has excellent diagnostic performance in identifying coronary arteries with ≥50% luminal stenosis on 3D QCA, outperforming standard-resolution imaging., Competing Interests: Funding Support and Author Disclosures This work was supported by British Heart Foundation grants FS/CRTF/23/24460, CH/F/21/90009, and RG/F/21/110040, the Onassis Foundation, the Oxford Biomedical Research Centre, and the NIHR Oxford Biomedical Research Centre Imaging and Cardiovascular Themes. Dr Antoniades holds several patents (US10,695,023B2, PCT/GB2017/053262, GB2018/1818049.7, GR20180100490, GR20180100510) licensed to Caristo Diagnostics; was recent Chair of the British Atherosclerosis Society; and has received honoraria from Amarin, Silence Therapeutics, Abcentra, Amgen, Nodthera, and Caristo Diagnostic. Drs Antoniades, Channon, and Neubauer are founders, shareholders, directors, and consultants of Caristo Diagnostics, a University of Oxford Spinout company. Dr Kotronias has received honoraria from Abbott. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose. The University of Oxford has a collaboration agreement with Siemens that allows access to advanced image analysis tools and prototype applications for research use., (Copyright © 2025 The Authors. Published by Elsevier Inc. All rights reserved.) more...

Introduction: Abnormal cardiorespiratory symptoms and investigative findings in service personnel typically result in prolonged investigation and occupational restriction. This analysis aimed to assess the impact of the O xford M ilitary Cardiopulmonary E xercise Testing C linic (OMEC), which investigates such symptoms and findings, on occupational recommendations., Methods: A service evaluation was conducted on all OMEC attendances over a 5-year period. Referral indication and occupational grading, demographics, exercise testing parameters, clinical diagnosis and occupational recommendation were recorded., Results: 141 individuals were reviewed. Mean age was 36 (±11.3) years, and 91% were male. Median waiting time for an appointment was 14.4 weeks (cf NHS 17.4 weeks).Individuals were referred for dyspnoea (22.1%), syncope (11.4%), chest pain (8.1%) (referred to as 'higher risk' symptom group), and pre-syncope (8.1%), palpitations (8.1%), and fatigue and/or exercise intolerance (6.0%) (referred to as 'lower risk' symptom group). 34% were asymptomatic with incidental findings on cardiac screening investigations. Reduced exercise capacity was rare, affecting only 11% of individuals, which was borderline/mild at worst.Median peak VO 2 (as a percentage of the predicted peak) was lower in the higher-risk symptom group than in the lower-risk symptom group (97.8% vs 121%; p<0.001). This was also seen for median workload as %PP (82.6% vs 98.0%; p<0.001). 80.5% of patients were given an immediate occupational recommendation; 78% of which were favourable outcomes (ie, a recommended occupational upgrade (72%) or to remain fully deployable (6%))., Conclusion: OMEC is tailored to the unique needs of the military population, providing outcomes that support operational requirements. Despite geographical distribution and operational commitments, OMEC waiting time is equivalent to the NHS, with the great majority of patients upgraded after attendance. These findings establish OMEC as a benchmark for military-specific clinical services based in public (NHS) hospitals, highlighting its role in facilitating rapid and effective occupational management., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2025. No commercial re-use. See rights and permissions. Published by BMJ Group.) more...

Objective: Post-COVID-19 syndrome presents a health and economic challenge affecting ~10% of patients recovering from COVID-19. Accurate assessment of patients with post-COVID-19 syndrome is complicated by health anxiety and coincident symptomatic autonomic dysfunction. We sought to determine whether either symptoms or objective cardiopulmonary exercise testing could predict clinically significant findings., Methods: 113 consecutive military patients were assessed in a comprehensive clinical pathway. This included symptom reporting, history, examination, spirometry, echocardiography and cardiopulmonary exercise testing (CPET) in all, with chest CT, dual-energy CT pulmonary angiography and cardiac MRI where indicated. Symptoms, CPET findings and presence/absence of significant pathology were reviewed. Data were analysed to identify diagnostic strategies that may be used to exclude significant disease., Results: 7/113 (6%) patients had clinically significant disease adjudicated by cardiothoracic multidisciplinary team (MDT). These patients had reduced fitness (V̇O 2 26.7 (±5.1) vs 34.6 (±7.0) mL/kg/min; p=0.002) and functional capacity (peak power 200 (±36) vs 247 (±55) W; p=0.026) compared with those without significant disease. Simple CPET criteria (oxygen uptake (V̇O 2 ) >100% predicted and minute ventilation (VE)/carbon dioxide elimination (V̇CO 2 ) slope <30.0 or VE/V̇CO 2 slope <35.0 in isolation) excluded significant disease with sensitivity and specificity of 86% and 83%, respectively (area under the receiver operating characteristic curve (AUC) 0.89). The addition of capillary blood gases to estimate alveolar-arterial gradient improved diagnostic performance to 100% sensitivity and 78% specificity (AUC 0.92). Symptoms and spirometry did not discriminate significant disease., Conclusions: In a population recovering from SARS-CoV-2, there is reassuringly little organ pathology. CPET and functional capacity testing, but not reported symptoms, permit the exclusion of clinically significant disease., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY. Published by BMJ.) more...

Accurate body temperature measurement is essential for monitoring and managing safety during outdoor activities. Physical activities are an essential consideration for public health, with sports taking up an important proportion of these. Athletes' performances can be directly affected by body temperature fluctuations, with overheating or hypothermia posing serious health risks. Monitoring these temperatures allows coaches and medical staff to make decisions that enhance performance and safety. Traditional methods, like oral, axillary, and tympanic readings, are widely used, but face challenges during intense physical activities in real-world environments. This study evaluated the agreement, correlation, and interchangeability of oral, axillary, and tympanic temperature measurements in outdoor exercise conditions. Systems developed for specific placements might generate different sensor readouts. Conducted as an observational field study, it involved 21 adult participants (11 males and 10 females, average age 25.14 ± 5.80 years) that underwent the Yo-Yo intermittent recovery test protocol on an outdoor court. The main outcomes measured were the agreement and correlation between temperature readings from the three methods, both before and after exercise. The results indicate poor agreement between the measurement sites, with significant deviations observed post-exercise. Although the Spearman correlation coefficients showed consistent temperature changes post-exercise across all methods, the standard deviations in the pairwise comparisons exceeded 0.67 °C. This study concluded that widely used temperature measurement methods are challenging to use during outdoor exercises and should not be considered interchangeable. This variability, especially after exercise, underscores the need for further research using gold standard temperature measurement methods to determine the most suitable site for accurate readings. Care should thus be taken when temperature screening is done at scale using traditional methods, as each measurement site should be considered within its own right. more...

Background: Significant numbers of individuals struggle to return to work following acute coronavirus disease 2019 (COVID-19). The UK Military developed an integrated medical and occupational pathway (Defence COVID-19 Recovery Service, DCRS) to ensure safe return to work for those with initially severe disease or persistent COVID-19 sequalae. Medical deployment status (MDS) is used to determine ability to perform job role without restriction ('fully deployable', FD) or with limitations ('medically downgraded', MDG)., Aims: To identify which variables differ between those who are FD and MDG 6 months after acute COVID-19. Within the downgraded cohort, a secondary aim is to understand which early factors are associated with persistent downgrading at 12 and 18 months., Methods: Individuals undergoing DCRS had comprehensive clinical assessment. Following this, their electronic medical records were reviewed and MDS extracted at 6, 12 and 18 months. Fifty-seven predictors taken from DCRS were analysed. Associations were sought between initial and prolonged MDG., Results: Three hundred and twenty-five participants were screened, with 222 included in the initial analysis. Those who were initially downgraded were more likely to have post-acute shortness of breath (SoB), fatigue and exercise intolerance (objective and subjective), cognitive impairment and report mental health symptoms. The presence of fatigue and SoB, cognitive impairment and mental health symptoms was associated with MDG at 12 months, and the latter two, at 18 months. There were also modest associations between cardiopulmonary function and sustained downgrading., Conclusions: Understanding the factors that are associated with initial and sustained inability to return to work allows individualized, targeted interventions to be utilized., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.) more...

Background: Since the COVID-19 pandemic, post-COVID syndrome (persistent symptoms/complications lasting >12 weeks) continues to pose medical and economic challenges. In military personnel, where optimal fitness is crucial, prolonged limitations affecting their ability to perform duties has occupational and psychological implications, impacting deployability and retention. Research investigating post-COVID syndrome exercise capacity and cardiopulmonary effects in military personnel is limited., Methods: UK military personnel were recruited from the Defence Medical Services COVID-19 Recovery Service. Participants were separated into healthy controls without prior SARS-CoV-2 infection (group one), and participants with prolonged symptoms (>12 weeks) after mild-moderate (community-treated) and severe (hospitalised) COVID-19 illness (group 2 and 3, respectively). Participants underwent cardiac magnetic resonance imaging (CMR) and spectroscopy, echocardiography, pulmonary function testing and cardiopulmonary exercise testing (CPET)., Results: 113 participants were recruited. When compared in ordered groups (one to three), CPET showed stepwise decreases in peak work, work at VT1 and VO 2 max (all p < 0.01). There were stepwise decreases in FVC (p = 0.002), FEV 1 (p = 0.005), TLC (p = 0.002), V A (p < 0.001), and DLCO (p < 0.002), and a stepwise increase in A-a gradient (p < 0.001). CMR showed stepwise decreases in LV/RV volumes, stroke volumes and LV mass (LVEDVi/RVEDVi p < 0.001; LVSV p = 0.003; RVSV p = 0.001; LV mass index p = 0.049)., Conclusion: In an active military population, post-COVID syndrome is linked to subclinical changes in maximal exercise capacity. Alongside disease specific changes, many of these findings share the phenotype of deconditioning following prolonged illness or bedrest. Partitioning of the relative contribution of pathological changes from COVID-19 and deconditioning is challenging in post-COVID syndrome recovery., Competing Interests: Declaration of Competing Interest None., (Copyright © 2023. Published by Elsevier B.V.) more...

Introduction: Fusion pacing requires correct timing of left ventricular pacing to right ventricular activation, although it is unclear whether this is maintained when atrioventricular (AV) conduction changes during exercise. We used cardiopulmonary exercise testing (CPET) to compare cardiac resynchronization therapy (CRT) using fusion pacing or fixed AV delays (AVD)., Methods: Patients 6 months post-CRT implant with PR intervals < 250 ms performed two CPET tests, using either the SyncAV™ algorithm or fixed AVD of 120 ms in a double-blinded, randomized, crossover study. All other programming was optimized to produce the narrowest QRS duration (QRSd) possible., Results: Twenty patients (11 male, age 71 [65-77] years) were recruited. Fixed AVD and fusion programming resulted in similar narrowing of QRSd from intrinsic rhythm at rest (p = .85). Overall, there was no difference in peak oxygen consumption (V̇O 2 PEAK , p = .19), oxygen consumption at anaerobic threshold (VT1, p = .42), or in the time to reach either V̇O 2 PEAK (p = .81) or VT1 (p = .39). The BORG rating of perceived exertion was similar between groups. CPET performance was also analyzed comparing whichever programming gave the narrowest QRSd at rest (119 [96-136] vs. 134 [119-142] ms, p < .01). QRSd during exercise (p = .03), peak O 2 pulse (mL/beat, a surrogate of stroke volume, p = .03), and cardiac efficiency (watts/mL/kg/min, p = .04) were significantly improved., Conclusion: Fusion pacing is maintained during exercise without impairing exercise capacity compared with fixed AVD. However, using whichever algorithm gives the narrowest QRSd at rest is associated with a narrower QRSd during exercise, higher peak stroke volume, and improved cardiac efficiency., (© 2023 The Authors. Journal of Cardiovascular Electrophysiology published by Wiley Periodicals LLC.) more...

Introduction: COVID-19 infection can precede, in a proportion of patients, a prolonged syndrome including fatigue, exercise intolerance, mood and cognitive problems. This study aimed to describe the profile of fatigue-related, exercise-related, mood-related and cognitive-related outcomes in a COVID-19-exposed group compared with controls., Methods: 113 serving UK Armed Forces participants were followed up at 5, 12 (n=88) and 18 months (n=70) following COVID-19. At 18 months, 56 were in the COVID-19-exposed group with 14 matched controls. Exposed participants included hospitalised (n=25) and community (n=31) managed participants. 43 described at least one of the six most frequent symptoms at 5 months: fatigue, shortness of breath, chest pain, joint pain, exercise intolerance and anosmia. Participants completed a symptom checklist, patient-reported outcome measures (PROMs), the National Institute for Health cognitive battery and a 6-minute walk test (6MWT). PROMs included the Fatigue Assessment Scale (FAS), Generalised Anxiety Disorder-7 (GAD-7), Patient Health Questionnaire-9 (PHQ-9) and Patient Checklist-5 (PCL-5) for post-traumatic stress., Results: At 5 and 12 months, exposed participants presented with higher PHQ-9, PCL-5 and FAS scores than controls (ES (effect size) ≥0.25, p≤0.04). By 12 months, GAD-7 was not significantly different to controls (ES <0.13, p=0.292). Remaining PROMs lost significant difference by 18 months (ES ≤0.11, p≥0.28). No significant differences in the cognitive scales were observed at any time point (F=1.96, p=0.167). At 5 and 12 months, exposed participants recorded significantly lower distances on the 6MWT (η p 2 ≥0.126, p<0.01). 6MWT distance lost significant difference by 18 months (η p 2 <0.039, p>0.15)., Conclusions: This prospective cohort-controlled study observed adverse outcomes in depression, post-traumatic stress, fatigue and submaximal exercise performance up to 12 months but improved by 18-month follow-up, in participants exposed to COVID-19 compared with a matched control group., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.) more...

Failure to recover following severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) may have a profound impact on individuals who participate in high-intensity/volume exercise as part of their occupation/recreation. The aim of this study was to describe the longitudinal cardiopulmonary exercise function, fatigue, and mental health status of military-trained individuals (up to 12-mo postinfection) who feel recovered, and those with persistent symptoms from two acute disease severity groups (hospitalized and community-managed), compared with an age-, sex-, and job role-matched control. Eighty-eight participants underwent cardiopulmonary functional tests at baseline (5 mo following acute illness) and 12 mo; 25 hospitalized with persistent symptoms (hospitalized-symptomatic), 6 hospitalized and recovered (hospitalized-recovered); 28 community-managed with persistent symptoms (community-symptomatic); 12 community-managed, now recovered (community-recovered), and 17 controls. Cardiopulmonary exercise function and mental health status were comparable between the 5 and 12-mo follow-up. At 12 mo, symptoms of fatigue (48% and 46%) and shortness of breath (SoB; 52% and 43%) remain high in hospitalized-symptomatic and community-symptomatic groups, respectively. At 12 mo, COVID-19-exposed participants had a reduced capacity for work at anaerobic threshold and at peak exercise levels of deconditioning persist, with many individuals struggling to return to strenuous activity. The prevalence considered "fully fit" at 12 mo was lowest in symptomatic groups (hospitalized-symptomatic, 4%; hospitalized-recovered, 50%; community-symptomatic, 18%; community-recovered, 82%; control, 82%) and 49% of COVID-19-exposed participants remained medically nondeployable within the British Armed Forces. For hospitalized and symptomatic individuals, cardiopulmonary exercise profiles are consistent with impaired metabolic efficiency and deconditioning at 12 mo postacute illness. The long-term deployability status of COVID-19-exposed military personnel is uncertain. NEW & NOTEWORTHY Subjective exercise limiting symptoms such as fatigue and shortness of breath reduce but remain prevalent in symptomatic groups. At 12 mo, COVID-19-exposed individuals still have a reduced capacity for work at the anaerobic threshold (which best predicts sustainable intensity), despite oxygen uptake comparable to controls. The prevalence of COVID-19-exposed individuals considered "medically non-deployable" remains high at 47%. more...

Detailed characterisation of cardiopulmonary limitations in patients post-COVID-19 is currently limited, particularly in elite athletes. A male elite distance runner in his late 30s experienced chest pain following confirmed COVID-19. He underwent cardiopulmonary exercise testing (CPET) at 5 months postacute illness. Subjective exercise tolerance was reduced compared with normal, he described inability to 'kick' (rapidly accelerate). His CPET was compared with an identical protocol 15 months prior to COVID-19. While supranormal maximal oxygen uptake was maintained (155% of peak predicted V̇O 2 ) anaerobic threshold (AT), a better predictor of endurance performance, reduced from 84% to 71% predicted peak V̇O 2 maximum. Likewise, fat oxidation at AT reduced by 21%, from 0.35 to 0.28 g/min. Focusing exclusively on V̇O 2 maximum risks missing an impairment of oxidative metabolism. Reduced AT suggests a peripheral disorder of aerobic metabolism. This finding may result from virally mediated mitochondrial dysfunction beyond normal 'deconditioning', associated with impaired fat oxidation., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2023. No commercial re-use. See rights and permissions. Published by BMJ.) more...

Background: The COVID-19 pandemic has led to significant morbidity and mortality, with the former impacting and limiting individuals requiring high physical fitness, including sportspeople and emergency services., Methods: Observational cohort study of 4 groups: hospitalised, community illness with on-going symptoms (community-symptomatic), community illness now recovered (community-recovered) and comparison. A total of 113 participants (aged 39 ± 9, 86% male) were recruited: hospitalised (n = 35), community-symptomatic (n = 34), community-recovered (n = 18) and comparison (n = 26), approximately five months following acute illness. Participant outcome measures included cardiopulmonary imaging, submaximal and maximal exercise testing, pulmonary function, cognitive assessment, blood tests and questionnaires on mental health and function., Results: Hospitalised and community-symptomatic groups were older (43 ± 9 and 37 ± 10, P = 0.003), with a higher body mass index (31 ± 4 and 29 ± 4, P < 0.001), and had worse mental health (anxiety, depression and post-traumatic stress), fatigue and quality of life scores. Hospitalised and community-symptomatic participants performed less well on sub-maximal and maximal exercise testing. Hospitalised individuals had impaired ventilatory efficiency (higher VE/V̇CO 2 slope, 29.6 ± 5.1, P < 0.001), achieved less work at anaerobic threshold (70 ± 15, P < 0.001) and peak (231 ± 35, P < 0.001), and had a reduced forced vital capacity (4.7 ± 0.9, P = 0.004). Clinically significant abnormal cardiopulmonary imaging findings were present in 6% of hospitalised participants. Community-recovered individuals had no significant differences in outcomes to the comparison group., Conclusion: Symptomatically recovered individuals who suffered mild-moderate acute COVID-19 do not differ from an age-, sex- and job-role-matched comparison population five months post-illness. Individuals who were hospitalised or continue to suffer symptoms may require a specific comprehensive assessment prior to return to full physical activity., (© 2023. Crown.) more...

The longer-term effects of COVID-19 on lung physiology remain poorly understood. Here, a new technique, computed cardiopulmonography (CCP), was used to study two COVID-19 cohorts (MCOVID and C-MORE-LP) at both ∼6 and ∼12 mo after infection. CCP is comprised of two components. The first is collection of highly precise, highly time-resolved measurements of gas exchange with a purpose-built molecular flow sensor based around laser absorption spectroscopy. The second component is estimation of physiological parameters by fitting a cardiopulmonary model to the data set. The measurement protocol involved 7 min of breathing air followed by 5 min of breathing pure O 2 . One hundred seventy-eight participants were studied, with 97 returning for a repeat assessment. One hundred twenty-six arterial blood gas samples were drawn from MCOVID participants. For participants who had required intensive care and/or invasive mechanical ventilation, there was a significant increase in anatomical dead space of ∼30 mL and a significant increase in alveolar-to-arterial Po 2 gradient of ∼0.9 kPa relative to control participants. Those who had been hospitalized had reductions in functional residual capacity of ∼15%. Irrespectively of COVID-19 severity, participants who had had COVID-19 demonstrated a modest increase in ventilation inhomogeneity, broadly equivalent to that associated with 15 yr of aging. This study illustrates the capability of CCP to study aspects of lung function not so easily addressed through standard clinical lung function tests. However, without measurements before infection, it is not possible to conclude whether the findings relate to the effects of COVID-19 or whether they constitute risk factors for more serious disease. NEW & NOTEWORTHY This study used a novel technique, computed cardiopulmonography, to study the lungs of patients who have had COVID-19. Depending on severity of infection, there were increases in anatomical dead space, reductions in absolute lung volumes, and increases in ventilation inhomogeneity broadly equivalent to those associated with 15 yr of aging. However, without measurements taken before infection, it is unclear whether the changes result from COVID-19 infection or are risk factors for more severe disease. more...

Background: Iron deficiency has deleterious effects in patients with cardiopulmonary disease, independent of anemia. Low ferritin has been associated with increased mortality in patients undergoing cardiac surgery, but modern indices of iron deficiency need to be explored in this population., Methods: We conducted a retrospective single-centre observational study of 250 adults in a UK academic tertiary hospital undergoing median sternotomy for non-emergent isolated aortic valve replacement. We characterised preoperative iron status using measurement of both plasma ferritin and soluble transferrin receptor (sTfR), and examined associations with clinical outcomes., Results: Measurement of plasma sTfR gave a prevalence of iron deficiency of 22%. Patients with non-anemic iron deficiency had clinically significant prolongation of total hospital stay (mean increase 2.2 days; 95% CI: 0.5-3.9; P = 0.011) and stay within the cardiac intensive care unit (mean increase 1.3 days; 95% CI: 0.1-2.5; P = 0.039). There were no deaths. Defining iron deficiency as a plasma ferritin < 100 µg/L identified 60% of patients as iron deficient and did not predict length of stay. No significant associations with transfusion requirements were evident using either definition of iron deficiency., Conclusions: These findings indicate that when defined using sTfR rather than ferritin, non-anemic iron deficiency predicts prolonged hospitalisation following surgical aortic valve replacement. Further studies are required to clarify the role of contemporary laboratory indices in the identification of preoperative iron deficiency in patients undergoing cardiac surgery. An interventional study of intravenous iron targeted at preoperative non-anemic iron deficiency is warranted., (© 2022. The Author(s).) more...

Introduction: There have been more than 425 million COVID-19 infections worldwide. Post-COVID illness has become a common, disabling complication of this infection. Therefore, it presents a significant challenge to global public health and economic activity., Methods: Comprehensive clinical assessment (symptoms, WHO performance status, cognitive testing, CPET, lung function, high-resolution CT chest, CT pulmonary angiogram and cardiac MRI) of previously well, working-age adults in full-time employment was conducted to identify physical and neurocognitive deficits in those with severe or prolonged COVID-19 illness., Results: 205 consecutive patients, age 39 (IQR30.0-46.7) years, 84% male, were assessed 24 (IQR17.1-34.0) weeks after acute illness. 69% reported ≥3 ongoing symptoms. Shortness of breath (61%), fatigue (54%) and cognitive problems (47%) were the most frequent symptoms, 17% met criteria for anxiety and 24% depression. 67% remained below pre-COVID performance status at 24 weeks. One third of lung function tests were abnormal, (reduced lung volume and transfer factor, and obstructive spirometry). HRCT lung was clinically indicated in <50% of patients, with COVID-associated pathology found in 25% of these. In all but three HRCTs, changes were graded 'mild'. There was an extremely low incidence of pulmonary thromboembolic disease or significant cardiac pathology. A specific, focal cognitive deficit was identified in those with ongoing symptoms of fatigue, poor concentration, poor memory, low mood, and anxiety. This was notably more common in patients managed in the community during their acute illness., Conclusion: Despite low rates of residual cardiopulmonary pathology, in this cohort, with low rates of premorbid illness, there is a high burden of symptoms and failure to regain pre-COVID performance 6-months after acute illness. Cognitive assessment identified a specific deficit of the same magnitude as intoxication at the UK drink driving limit or the deterioration expected with 10 years ageing, which appears to contribute significantly to the symptomatology of long-COVID., Competing Interests: The authors have declared that no competing interests exist. more...

A failure to fully recover following coronavirus disease 2019 (COVID-19) may have a profound impact on high-functioning populations ranging from frontline emergency services to professional or amateur/recreational athletes. The aim of the study is to describe the medium-term cardiopulmonary exercise profiles of individuals with "persistent symptoms" and individuals who feel "recovered" after hospitalization or mild-moderate community infection following COVID-19 to an age, sex, and job-role matched control group. A total of 113 participants underwent cardiopulmonary functional tests at a mean of 159 ± 7 days (∼5 mo) following acute illness; 27 hospitalized with persistent symptoms (hospitalized-symptomatic), 8 hospitalized and now recovered (hospitalized-recovered); 34 community managed with persistent symptoms (community-symptomatic); 18 community managed and now recovered (community-recovered); and 26 controls. Hospitalized groups had the least favorable body composition (body mass, body mass index, and waist circumference) compared with controls. Hospitalized-symptomatic and community-symptomatic individuals had a lower oxygen uptake (V̇o 2 ) at peak exercise (hospitalized-symptomatic, 29.9 ± 5.0 mL/kg/min; community-symptomatic, 34.4 ± 7.2 mL/kg/min; vs. control 43.9 ± 3.1 mL/kg/min, both P < 0.001). Hospitalized-symptomatic individuals had a steeper V̇e/V̇co 2 slope (lower ventilatory efficiency) (30.5 ± 5.3 vs. 25.5 ± 2.6, P = 0.003) versus. controls. Hospitalized-recovered had a significantly lower oxygen uptake at peak (32.6 ± 6.6 mL/kg/min vs. 43.9 ± 13.1 mL/kg/min, P = 0.015) compared with controls. No significant differences were reported between community-recovered individuals and controls in any cardiopulmonary parameter. In conclusion, medium-term findings suggest that community-recovered individuals did not differ in cardiopulmonary fitness from physically active healthy controls. This suggests their readiness to return to higher levels of physical activity. However, the hospitalized-recovered group and both groups with persistent symptoms had enduring functional limitations, warranting further monitoring, rehabilitation, and recovery. NEW & NOTEWORTHY At 5 mo postinfection, community-treated individuals who feel recovered have comparable cardiopulmonary exercise profiles to the physically trained and active controls, suggesting a readiness to return to higher intensity/volumes of exercise. However, both symptomatic groups and the hospital-recovered group have persistent functional limitations when compared with active controls, supporting the requirement for ongoing monitoring, rehabilitation, and recovery. more...

Background: Individuals who contract coronavirus disease 2019 (COVID-19) can suffer with persistent and debilitating symptoms long after the initial acute illness. Heart rate (HR) profiles determined during cardiopulmonary exercise testing (CPET) and delivered as part of a post-COVID recovery service may provide insight into the presence and impact of dysautonomia on functional ability., Objective: Using an active, working-age, post-COVID-19 population, the purpose of this study was to (1) determine and characterize any association between subjective symptoms and dysautonomia; and (2) identify objective exercise capacity differences between patients classified "with" and those "without" dysautonomia., Methods: Patients referred to a post-COVID-19 service underwent comprehensive clinical assessment, including self-reported symptoms, CPET, and secondary care investigations when indicated. Resting HR >75 bpm, HR increase with exercise <89 bpm, and HR recovery <25 bpm 1 minute after exercise were used to define dysautonomia. Anonymized data were analyzed and associations with symptoms, and CPET outcomes were determined., Results: Fifty-one of the 205 patients (25%) reviewed as part of this service evaluation had dysautonomia. There were no associations between symptoms or perceived functional limitation and dysautonomia (P >.05). Patients with dysautonomia demonstrated objective functional limitations with significantly reduced work rate (219 ± 37 W vs 253 ± 52 W; P <.001) and peak oxygen consumption (V̇o 2 : 30.6 ± 5.5 mL/kg/min vs 35.8 ± 7.6 mL/kg/min; P <.001); and a steeper (less efficient) V̇e/V̇co 2 slope (29.9 ± 4.9 vs 27.7 ± 4.7; P = .005)., Conclusion: Dysautonomia is associated with objective functional limitations but is not associated with subjective symptoms or limitation., (Crown Copyright © 2021. Published by Elsevier Inc. All rights reserved.) more...

Iron deficiency impairs skeletal muscle metabolism. The underlying mechanisms are incompletely characterised, but animal and human experiments suggest the involvement of signalling pathways co-dependent upon oxygen and iron availability, including the pathway associated with hypoxia-inducible factor (HIF). We performed a prospective, case-control, clinical physiology study to explore the effects of iron deficiency on human metabolism, using exercise as a stressor. Thirteen iron-deficient (ID) individuals and thirteen iron-replete (IR) control participants each underwent 31 P-magnetic resonance spectroscopy of exercising calf muscle to investigate differences in oxidative phosphorylation, followed by whole-body cardiopulmonary exercise testing. Thereafter, individuals were given an intravenous (IV) infusion, randomised to either iron or saline, and the assessments repeated ~ 1 week later. Neither baseline iron status nor IV iron significantly influenced high-energy phosphate metabolism. During submaximal cardiopulmonary exercise, the rate of decline in blood lactate concentration was diminished in the ID group (P = 0.005). Intravenous iron corrected this abnormality. Furthermore, IV iron increased lactate threshold during maximal cardiopulmonary exercise by ~ 10%, regardless of baseline iron status. These findings demonstrate abnormal whole-body energy metabolism in iron-deficient but otherwise healthy humans. Iron deficiency promotes a more glycolytic phenotype without having a detectable effect on mitochondrial bioenergetics., (© 2022. The Author(s).) more...

Heat adaption through acclimatisation or acclimation improves cardiovascular stability by maintaining cardiac output due to compensatory increases in stroke volume. The main aim of this study was to assess whether 2D transthoracic echocardiography (TTE) could be used to confirm differences in resting echocardiographic parameters, before and after active heat acclimation (HA). Thirteen male endurance trained cyclists underwent a resting blinded TTE before and after randomisation to either 5 consecutive daily exertional heat exposures of controlled hyperthermia at 32°C with 70% relative humidity (RH) (HOT) or 5-days of exercise in temperate (21°C with 36% RH) environmental conditions (TEMP). Measures of HA included heart rate, gastrointestinal temperature, skin temperature, sweat loss, total non-urinary fluid loss (TNUFL), plasma volume and participant's ratings of perceived exertion (RPE). Following HA, the HOT group demonstrated increased sweat loss (p = 0.01) and TNUFL (p = 0.01) in comparison to the TEMP group with a significantly decreased RPE (p = 0.01). On TTE, post exposure, there was a significant comparative increase in the HOT group in left ventricular end diastolic volume (p = 0.029), SV (p = 0.009), left atrial volume (p = 0.005), inferior vena cava diameter (p = 0.041), and a significant difference in mean peak diastolic mitral annular velocity (e') (p = 0.044). Cardiovascular adaptations to HA appear to be predominantly mediated by improvements in increased preload and ventricular compliance. TTE is a useful tool to demonstrate and quantify cardiac HA., (Copyright © 2020 Elsevier Ltd. All rights reserved.) more...

Background: The benefit of cardiovascular magnetic resonance Imaging (CMR) in assessing occupational risk is unknown. Pilots undergo frequent medical assessment for occult disease, which threatens incapacitation or distraction during flight. ECG and examination anomalies often lead to lengthy restriction, pending full investigation. CMR provides a sensitive, specific assessment of cardiac anatomy, tissue characterisation, perfusion defects and myocardial viability. We sought to determine if CMR, when added to standard care, would alter occupational outcome., Methods: A retrospective review was conducted of all personnel attending the RAF Aviation Medicine Consultation Service (AMCS) for assessment of a cardiac anomaly, over a 2-year period. Those undergoing standard of care (history, examination, exercise ECG, 24 h-Holter and transthoracic echocardiography), and those undergoing a CMR in addition, were identified. The influence of CMR upon the final decision regarding flying restriction was determined by comparing the diagnosis reached with standard of care plus CMR vs. standard of care alone., Results: Of the ~ 8000 UK military aircrew, 558 personnel were seen for cardiovascular assessment. Fifty-two underwent CMR. A normal TTE did not reliably exclude abnormalities subsequently detected by CMR. Addition of CMR resulted in an upgraded occupational status in 62% of those investigated, with 37% returning to unrestricted duties. Only 8% of referrals were undiagnosed following CMR. All these were cases of borderline chamber dilatation and reduction in systolic function in whom diagnostic uncertainty remained between physiological exercise adaptation and early cardiomyopathy., Conclusions: CMR increases the likelihood of a definitive diagnosis and of return to flying. This study supports early use of CMR in occupational assessment for high-hazard occupations. more...

Introduction: The autonomic system and sympathetic activation appears integral in the pathogenesis of acute mountain sickness (AMS) at high altitude (HA), yet a link between heart rate variability (HRV) and AMS has not been convincingly shown. In this study we investigated the utility of the smartphone-derived HRV score to predict and diagnose AMS at HA., Methods: Twenty-one healthy adults were investigated at baseline at 1400 m and over 10 days during a trek to 5140 m. HRV was recorded using the ithlete HRV device., Results: Acute mountain sickness occurred in 11 subjects (52.4%) at >2650 m. HRV inversely correlated with AMS Scores (r = -0.26; 95% CI, -0.38 to -0.13: P < 0.001). HRV significantly fell at 3700, 4100, and 5140 m versus low altitude. HRV scores were lower in those with both mild (69.7 ± 14.0) and severe AMS (67.1 ± 13.1) versus those without AMS (77.5 ± 13.1; effect size n = 0.043: P = 0.007). The HRV score was weakly predictive of severe AMS (AUC 0.74; 95% CI, 0.58-0.89: P = 0.006). The change (delta) in the HRV Score (compared with baseline at 1400 m) was a moderate diagnostic marker of severe AMS (AUC 0.80; 95% CI, 0.70-0.90; P = 0.0004). A fall in the HRV score of >5 had a sensitivity of 83% and specificity of 60% to identify severe AMS (likelihood ratio 1.9). Baseline HRV at 1400 m was not predictive of either AMS at higher altitudes., Conclusions: The ithlete HRV score can be used to help in the identification of severe AMS; however, a baseline score is not predictive of future AMS development at HA. more...

Introduction: Physical endurance can be limited by muscle glycogen stores, in that glycogen depletion markedly reduces external work. During carbohydrate restriction, the liver synthesizes the ketone bodies, D-β-hydroxybutyrate, and acetoacetate from fatty acids. In animals and in the presence of glucose, D-β-hydroxybutyrate promotes insulin secretion and increases glycogen synthesis. Here we determined whether a dietary ketone ester, combined with plentiful glucose, can increase postexercise glycogen synthesis in human skeletal muscle., Methods: After an interval-based glycogen depletion exercise protocol, 12 well-trained male athletes completed a randomized, three-arm, blinded crossover recovery study that consisted of consumption of either a taste-matched, zero-calorie control or a ketone monoester drink, followed by a 10-mM glucose clamp or saline infusion for 2 h. The three postexercise conditions were control drink then saline infusion, control drink then hyperglycemic clamp, or ketone ester drink then hyperglycemic clamp. Skeletal muscle glycogen content was determined in muscle biopsies of vastus lateralis taken before and after the 2-h clamps., Results: The ketone ester drink increased blood D-β-hydroxybutyrate concentrations to a maximum of 5.3 versus 0.7 mM for the control drink (P < 0.0001). During the 2-h glucose clamps, insulin levels were twofold higher (31 vs 16 mU·L, P < 0.01) and glucose uptake 32% faster (1.66 vs 1.26 g·kg, P < 0.001). The ketone drink increased by 61 g, the total glucose infused for 2 h, from 197 to 258 g, and muscle glycogen was 50% higher (246 vs 164 mmol glycosyl units per kilogram dry weight, P < 0.05) than after the control drink., Conclusion: In the presence of constant high glucose concentrations, a ketone ester drink increased endogenous insulin levels, glucose uptake, and muscle glycogen synthesis. more...

This study compared the effects of coingesting glucose and fructose on exogenous and endogenous substrate oxidation during prolonged exercise at altitude and sea level, in men. Seven male British military personnel completed two bouts of cycling at the same relative workload (55% W max ) for 120 min on acute exposure to altitude (3375 m) and at sea level (~113 m). In each trial, participants ingested 1.2 g·min -1 of glucose (enriched with 13 C glucose) and 0.6 g·min -1 of fructose (enriched with 13 C fructose) directly before and every 15 min during exercise. Indirect calorimetry and isotope ratio mass spectrometry were used to calculate fat oxidation, total and exogenous carbohydrate oxidation, plasma glucose oxidation, and endogenous glucose oxidation derived from liver and muscle glycogen. Total carbohydrate oxidation during the exercise period was lower at altitude (157.7 ± 56.3 g) than sea level (286.5 ± 56.2 g, P = 0.006, ES = 2.28), whereas fat oxidation was higher at altitude (75.5 ± 26.8 g) than sea level (42.5 ± 21.3 g, P = 0.024, ES = 1.23). Peak exogenous carbohydrate oxidation was lower at altitude (1.13 ± 0.2 g·min -1 ) than sea level (1.42 ± 0.16 g·min -1 , P = 0.034, ES = 1.33). There were no differences in rates, or absolute and relative contributions of plasma or liver glucose oxidation between conditions during the second hour of exercise. However, absolute and relative contributions of muscle glycogen during the second hour were lower at altitude (29.3 ± 28.9 g, 16.6 ± 15.2%) than sea level (78.7 ± 5.2 g (P = 0.008, ES = 1.71), 37.7 ± 13.0% (P = 0.016, ES = 1.45). Acute exposure to altitude reduces the reliance on muscle glycogen and increases fat oxidation during prolonged cycling in men compared with sea level., (© 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.) more...

Cardiomyopathies are a group of heterogeneous myocardial diseases that are frequently inherited and are a recognised cause of premature sudden cardiac death in young individuals. Incomplete expressions of disease and the overlap with the physiological cardiac manifestations of regular intensive exercise create diagnostic challenges in young athletes and military recruits. Early identification is important because sudden death in the absence of prodromal symptoms is a common presentation, and there are several therapeutic strategies to minimise this risk. This paper examines the classification and clinical features of cardiomyopathies with specific reference to a military population and provides a detailed account of the optimum strategy for diagnosis, indications for specialist referral and specific guidance on the occupational significance of cardiomyopathy. A 27-year-old Lance Corporal Signaller presents to his Regimental medical officer (RMO) after feeling 'light-headed' following an 8 mile unloaded run. While waiting to see the RMO, the medical sergeant records a 12-lead ECG. The ECG is reviewed by the RMO immediately prior to the consultation and shows voltage criteria for left ventricular (LV) hypertrophy and inverted T-waves in II, III, aVF and V1-V3 (Figure 1). This Lance Corporal is a unit physical training instructor and engages in >10 h of aerobic exercise per week. He is a non-smoker and does not have any significant medical history., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.) more...

Hypertension and hypertension-related diseases are a leading cause of morbidity and mortality worldwide. A diagnosis of hypertension can have serious occupational implications for military personnel. This article examines the diagnosis and management of hypertension in military personnel, in the context of current international standards. We consider the consequences of hypertension in the military environment and potential military-specific issues relating to hypertension., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.) more...

'Palpitations' include a broad range of symptoms relating to the perception of abnormal activity of the heart. They may reflect an underlying arrhythmia or a hyperawareness of normal cardiac activity caused by stress or anxiety. The challenge to a clinician assessing patients with palpitations is to assess the likely cause of symptoms, to stratify the individual patient risk and to choose the correct management strategy delivered with appropriate urgency. The young military population, subject to increased exposure to environmental stress, is at an increased risk of palpitations. Due to the distracting nature of this symptom and the frequently sudden and unheralded onset, a common consequence is medical downgrading. This article will provide a guide to assessing the heterogeneous group presenting with palpitations and how to both establish the cause and identify the correct treatment for each patient in a timely manner., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.) more...

Valvular heart disease refers to all inherited and acquired abnormalities impairing the function of one or more of the four cardiac valves. Pathology may be of the valve leaflets themselves, of the subvalvular apparatus or of the annulus or other surrounding structures that influences valve function. This paper examines the most common valve lesions, with specific reference to a military population; it focuses on detection and initial management of valve disease in a young adult population and specifically describes how the diagnosis and treatment of valve disease impacts military medical grading., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.) more...

Fluid retention is a recognized feature of acute mountain sickness. However, accurate assessment of hydration, including the quantification of body water, has traditionally relied on expensive and non-portable equipment limiting its utility in the field setting. We compared the assessment of total body water (TBW) and their relationship to total body weight using two non-invasive methods using the NICas single-frequency bioimpedance analysis (SF-BIA) system and the BodyStat QuadScan 4000 multifrequency BIA system (MF-BIA). TBW measurements were performed at rest at sea level and at high altitude (HA) at 3833 m postexercise and at rest and thereafter at rest at 4450 m and 5129 m on 47 subjects. The average age was 34.5 ± 9.3 years with an age range of 21-54 years (70.2% male). There were strong correlations between TBW assessment with both methods at sea level (r = 0.90; 95% CI 0.78-0.95: P<0.0001) and at HA (r = 0.92; 0.89-0.94: P<0.0001), however, TBW readings were 0.2 l and 1.91 l lower, respectively, with the NICaS. There was a stronger correlation between TBW and body weight with the QuadScan (r = 0.91; P<0.0001) than with the NICaS (r = 0.83; P<0.0001). The overall agreement between the two TBW methods was good, but the 95% confidence intervals around these agreements were relatively wide. We conclude that there was reasonable agreement between the two methods of BIA for TBW, but this agreement was lower at HA., (© 2014 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.) more...