Different approaches are used to classify obesity severity. Beyond classical anthropometric measurements, the Edmonton Obesity Staging System (EOSS) considers medical, physical and psychological ...parameters. However, this method has some limitations, principally due to the absence of an objective measure for physical impairment. The aim of our study is thus to overcome this limitation suggesting a new functional parameter obtained by cardiopulmonary exercise testing (CPET), i.e., cardiorespiratory fitness (CRF), expressed as weight-adjusted peak oxygen consumption (VO
peak/kg).
This observational cross-sectional study conducted on a population of 843 patients affected by obesity finally enrolled 500 subjects. Every patient underwent clinical, anthropometric, biochemical assessment and CPET. First, participants have been classified according to standard EOSS in five stages. Second, patients were reclassified according to the new modified EOSS (EOSS-CRF) based on their age- and gender-appropriate VO
peak/kg percentiles as reported in the healthy normal-weight population of the FRIEND registry.
VO
peak/kg was significantly different between standard EOSS classes 1 and 2 and classes 1 and 3 (ANCOVA p model = 0.004), whereas patients in classes 2 and 3 showed similar CRF. The EOSS-CRF classification varied in number of patients in each class compared to EOSS, particularly with a shift from class 2 to class 3. Moreover, CRF showed that physical impairment is less addressed by EOSS when compared to EOSS-CRF.
The integration of EOSS with CRF allowed us to assign to each patient a severity index that considers not only clinical parameters, but also their functional impairment through a quantitative and prognostically important parameter (VO
peak/kg). This improvement of the staging system may also provide a better approach to identify individuals at increased risk of mortality leading to targeted therapeutic management and prognostic risk stratification for patients with obesity.
This is the first study to independently assess the concurrent validity and reliability of the My Jump 2 app for measuring drop jump performance. It is also the first to evaluate the app's ability to ...measure the reactive strength index (RSI).
Fourteen male sport science students (age: 29.5±9.9 years) performed three drop jumps from 20 cm and 40 cm (totaling 84 jumps), assessed via a force platform and the My Jump 2 app. Reported metrics included reactive strength index, jump height, ground contact time, and mean power. Measurements from both devices were compared using the intraclass correlation coefficient (ICC), Pearson product moment correlation coefficient (r), Cronbach's alpha (α), coefficient of variation (CV) and Bland-Altman plots.
Near perfect agreement was seen between devices at 20 cm for RSI (ICC=0.95) and contact time (ICC=0.99) and at 40 cm for RSI (ICC=0.98), jump height (ICC=0.96) and contact time (ICC=0.92); with very strong agreement seen at 20 cm for jump height (ICC=0.80). In comparison with the force plate the app showed good validity for RSI (20 cm: r=0.94; 40 cm; r=0.97), jump height (20 cm: r=0.80; 40 cm; r=0.96) and contact time (20 cm=0.96; 40 cm; r=0.98).
The results of the present study show that the My Jump 2 app is a valid and reliable tool for assessing drop jump performance.
Paroxysmal and permanent atrial fibrillation (AF) are common in heart failure with preserved ejection fraction (HFpEF).
This study sought to determine the implications of left atrial (LA) myopathy ...and dysrhythmia across the spectrum of AF burden in HFpEF.
Consecutive patients with HFpEF (n = 285) and control subjects (n = 146) underwent invasive exercise testing and echocardiographic assessment of cardiac structure, function, and pericardial restraint.
Patients with HFpEF were categorized into stages of AF progression: 181 (65%) had no history of AF, 49 (18%) had paroxysmal AF, and 48 (17%) had permanent AF. Patients with permanent AF were more congested with greater pulmonary vascular disease and lower cardiac output. LA volumes increased, while LA compliance, LA reservoir strain, and right ventricular function decreased with increasing AF burden. The presence of permanent AF was characterized by a distinct pathophysiology, with greater total heart volume caused by atrial dilatation, leading to elevated filling pressures through heightened pericardial restraint. Survival decreased with increasing AF burden. Ten-year progression to permanent AF was common, particularly in paroxysmal AF (52%), and the likelihood of AF progression increased with higher AF stage, poorer LA compliance, and lower LA strain.
LA compliance and mechanics progressively decline with increasing AF burden in HFpEF, increasing risk for new onset AF and progressive AF. These changes promote development of a unique phenotype of HFpEF characterized by heightened ventricular interaction, right heart failure, and worsening pulmonary vascular disease. Further study is required to identify therapeutic interventions targeting LA myopathy to improve outcomes in HFpEF.
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Exertional breathlessness is a cardinal symptom of cardiorespiratory disease.
How does breathlessness abnormality, graded using normative reference equations during cardiopulmonary exercise testing ...(CPET), relate to self-reported and physiologic responses in people with chronic airflow limitation (CAL)?
An analysis was done of people aged ≥ 40 years with CAL undergoing CPET in the Canadian Cohort Obstructive Lung Disease study. Breathlessness intensity ratings (Borg CR10 scale 0-10 category-ratio scale for breathlessness intensity rating) were evaluated in relation to power output, rate of oxygen uptake, and minute ventilation at peak exercise, using normative reference equations as follows: (1) probability of breathlessness normality (probability of having an equal or greater Borg CR10 rating among healthy people; lower probability reflecting more severe breathlessness) and (2) presence of abnormal breathlessness (rating above the upper limit of normal). Associations with relevant participant-reported and physiologic outcomes were evaluated.
We included 330 participants (44% women): mean ± SD age, 64 ± 10 years (range, 40–89 years); FEV1/FVC, 57.3% ± 8.2%; FEV1, 75.6% ± 17.9% predicted. Abnormally low exercise capacity (peak rate of oxygen uptake < lower limit of normal) was present in 26%. Relative to peak power output, rate of oxygen uptake, and minute ventilation, abnormally high breathlessness was present in 26%, 25%, and 18% of participants. For all equations, abnormally high exertional breathlessness was associated with worse lung function, exercise capacity, self-reported symptom burden, physical activity, and health-related quality of life; and greater physiologic abnormalities during CPET.
Abnormal breathlessness graded using CPET normative reference equations was associated with worse clinical, physiological, and functional outcomes in people with CAL, supporting construct validity of abnormal exertional breathlessness.
Accurate assessment of functional capacity, a predictor of postoperative morbidity and mortality, is essential to improving surgical planning and outcomes. We assessed if all 12 items of the Duke ...Activity Status Index (DASI) were equally important in reflecting exercise capacity.
In this secondary cross-sectional analysis of the international, multicentre Measurement of Exercise Tolerance before Surgery (METS) study, we assessed cardiopulmonary exercise testing and DASI data from 1455 participants. Multivariable regression analyses were used to revise the DASI model in predicting an anaerobic threshold (AT) >11 ml kg−1 min−1 and peak oxygen consumption (VO2 peak) >16 ml kg−1 min−1, cut-points that represent a reduced risk of postoperative complications.
Five questions were identified to have dominance in predicting AT>11 ml kg−1 min−1 and VO2 peak>16 ml.kg−1min−1. These items were included in the M-DASI-5Q and retained utility in predicting AT>11 ml.kg−1.min−1 (area under the receiver-operating-characteristic AUROC-AT: M-DASI-5Q=0.67 vs original 12-question DASI=0.66) and VO2 peak (AUROC-VO2 peak: M-DASI-5Q 0.73 vs original 12-question DASI 0.71). Conversely, in a sensitivity analysis we removed one potentially sensitive question related to the ability to have sexual relations, and the ability of the remaining four questions (M-DASI-4Q) to predict an adequate functional threshold remained no worse than the original 12-question DASI model. Adding a dynamic component to the M-DASI-4Q by assessing the chronotropic response to exercise improved its ability to discriminate between those with VO2 peak>16 ml.kg−1.min−1 and VO2 peak<16 ml.kg−1.min−1.
The M-DASI provides a simple screening tool for further preoperative evaluation, including with cardiopulmonary exercise testing, to guide perioperative management.
To investigate the relationship between maximal exercise capacity measured before severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and hospitalization due to coronavirus disease ...2019 (COVID-19).
We identified patients (≥18 years) who completed a clinically indicated exercise stress test between January 1, 2016, and February 29, 2020, and had a test for SARS-CoV-2 (ie, real-time reverse transcriptase polymerase chain reaction test) between February 29, 2020, and May 30, 2020. Maximal exercise capacity was quantified in metabolic equivalents of task (METs). Logistic regression was used to evaluate the likelihood that hospitalization secondary to COVID-19 is related to peak METs, with adjustment for 13 covariates previously identified as associated with higher risk for severe illness from COVID-19.
We identified 246 patients (age, 59±12 years; 42% male; 75% black race) who had an exercise test and tested positive for SARS-CoV-2. Among these, 89 (36%) were hospitalized. Peak METs were significantly lower (P<.001) among patients who were hospitalized (6.7±2.8) compared with those not hospitalized (8.0±2.4). Peak METs were inversely associated with the likelihood of hospitalization in unadjusted (odds ratio, 0.83; 95% CI, 0.74-0.92) and adjusted models (odds ratio, 0.87; 95% CI, 0.76-0.99).
Maximal exercise capacity is independently and inversely associated with the likelihood of hospitalization due to COVID-19. These data further support the important relationship between cardiorespiratory fitness and health outcomes. Future studies are needed to determine whether improving maximal exercise capacity is associated with lower risk of complications due to viral infections, such as COVID-19.
Variables derived from the cardiopulmonary exercise test (CPX) provide objective information regarding the exercise capacity of children with cerebral palsy (CP), which can be used as the basis for ...exercise recommendations. Performing maximal CPX might not be appropriate, safe, or practical for children with CP. In the present study, the safety and feasibility of symptom-limited CPX using the modified Naughton protocol, a submaximal protocol, were investigated in children with CP, Gross Motor Function Classification System (GMFCS) level I or II. The present study included 40 children aged 6 to 12 years with CP who underwent symptom-limited CPX. CPX was performed to measure cardiopulmonary fitness using a treadmill with a modified Naughton protocol. Motor capacity was assessed using the Gross Motor Function Measure (GMFM), Pediatric Balance Scale (PBS), Timed Up and Go (TUG) test, and 6-minute walk test. Thirty-seven children with CP successfully completed testing without any adverse events during or immediately after CPX (dropout rate 7.5%). The reason for test termination was dyspnea (51.4%) or leg fatigue (48.6%). Based on the respiratory exchange ratio (RER), 21 of 37 (56.8%) children chose premature termination. The relationship between the reason for test termination and RER was not statistically significant (Spearman rho = 0.082, P = .631). CPX exercise time was strongly correlated with GMFM (Spearman rho = 0.714) and moderate correlation with PBS (Spearman rho = 0.690) and TUG (Spearman rho = 0.537). Peak oxygen uptake during CPX showed a weak correlation with GMFM and a moderate correlation with PBS. This study revealed that symptom-limited CPX using the modified Naughton protocol was safe and feasible for children with CP and GMFCS level I or II.
Equations are often used to predict cardiorespiratory fitness (CRF) from submaximal or maximal exercise tests. However, no study has comprehensively compared these exercise-based equations with ...directly measured CRF using data from a single, large cohort.
PURPOSEThis study aimed to compare the accuracy of exercise-based prediction equations with directly measured CRF and evaluate their ability to classify an individual’s CRF.
METHODSThe sample included 4871 tests from apparently healthy adults (38% female, age 44.4 ± 12.3 yr (mean ± SD)). Estimated CRF (eCRF) was determined from 2 nonexercise equations, 3 submaximal exercise equations, and 10 maximal exercise equations; all eCRF calculations were then compared with directly measured CRF, determined from a cardiopulmonary exercise test. Analysis included Pearson product–moment correlations, standard error of estimate values, intraclass correlation coefficients, Cohen κ coefficients, and the Benjamini–Hochberg procedure to compare eCRF with directly measured CRF.
RESULTSAll eCRF values from the prediction equations were associated with directly measured CRF (P < 0.01), with intraclass correlation coefficient estimates ranging from 0.07 to 0.89. Although significant agreement was found when using eCRF to categorize participants into fitness tertiles, submaximal exercise equations correctly classified an average of only 51% (range, 37%–58%) and maximal exercise equations correctly classified an average of only 59% (range, 43%–76%).
CONCLUSIONSDespite significant associations between exercise-based prediction equations and directly measured CRF, the equations had a low degree of accuracy in categorizing participants into fitness tertiles, a key requirement when stratifying risk within a clinical setting. The present analysis highlights the limited accuracy of exercise-based determinations of eCRF and suggests the need to include cardiopulmonary measures with maximal exercise to accurately assess CRF within a clinical setting.
The anaerobic threshold (AT) remains a widely recognized, and contentious, concept in exercise physiology and medicine. As conceived by Karlman Wasserman, the AT coalesced the increase of blood ...lactate concentration (La−), during a progressive exercise test, with an excess pulmonary carbon dioxide output (V̇CO2). Its principal tenets were: limiting oxygen (O2) delivery to exercising muscle→increased glycolysis, La− and H+ production→decreased muscle and blood pH→with increased H+ buffered by blood HCO3−→increased CO2 release from blood→increased V̇CO2 and pulmonary ventilation. This schema stimulated scientific scrutiny which challenged the fundamental premise that muscle anoxia was requisite for increased muscle and blood La−. It is now recognized that insufficient O2 is not the primary basis for lactataemia. Increased production and utilization of La− represent the response to increased glycolytic flux elicited by increasing work rate, and determine the oxygen uptake (V̇O2) at which La− accumulates in the arterial blood (the lactate threshold; LT). However, the threshold for a sustained non‐oxidative contribution to exercise energetics is the critical power, which occurs at a metabolic rate often far above the LT and separates heavy from very heavy/severe‐intensity exercise. Lactate is now appreciated as a crucial energy source, major gluconeogenic precursor and signalling molecule but there is no ipso facto evidence for muscle dysoxia or anoxia. Non‐invasive estimation of LT using the gas exchange threshold (non‐linear increase of V̇CO2 versus V̇O2) remains important in exercise training and in the clinic, but its conceptual basis should now be understood in light of lactate shuttle biology.
figure legend As originally posited and defended most ardently by Karlman Wasserman and Brian J. Whipp, the anaerobic threshold (AT) concept represents the epitome of integrative physiological control. The graph at the upper right portrays blood La−, arterial CO2 partial pressure (PCO2) and ventilation (V̇E) as a function of V̇O2 increasing from rest to maximum (V̇O2max). The AT is identified (black arrow) by the departure of V̇E from linearity without PCO2 decreasing. As shown rightwards from the ‘Original theory’ box, the AT held that lack of (or very low) muscle O2, via the Pasteur effect, increased muscle and blood lactic acid, then H+ dissociated from the lactic acid and was buffered by bicarbonate thus increasing CO2 evolution from the blood; this stimulated the ‘extra’ V̇E at AT simultaneous with the increase in La−. Currently we understand that neither anoxia nor dysoxia underpins increased muscle La− production and efflux, but rather its increase in the blood is attributed to the rate of La− appearance being greater than disappearance. Also, as long appreciated, the variability in, and complexities of, the control of breathing dictate that the V̇CO2 versus V̇O2 relation (gas exchange threshold) more reliably approximates the lactate threshold than does the ventilatory profile. At the bottom, the modern understanding of metabolism is that La− is a central element linking glycolysis (Gly) and oxidative phosphorylation (OxPhos) energetics. Via cell signalling, La− also plays roles in short‐ and long‐term adaptations in both health and disease.
BACKGROUND:Optimal management of patients with stable chest pain relies on the prognostic information provided by noninvasive cardiovascular testing, but there are limited data from randomized trials ...comparing anatomic with functional testing.
METHODS:In the PROMISE trial (Prospective Multicenter Imaging Study for Evaluation of Chest Pain), patients with stable chest pain and intermediate pretest probability for obstructive coronary artery disease (CAD) were randomly assigned to functional testing (exercise electrocardiography, nuclear stress, or stress echocardiography) or coronary computed tomography angiography (CTA). Site-based diagnostic test reports were classified as normal or mildly, moderately, or severely abnormal. The primary end point was death, myocardial infarction, or unstable angina hospitalizations over a median follow-up of 26.1 months.
RESULTS:Both the prevalence of normal test results and incidence rate of events in these patients were significantly lower among 4500 patients randomly assigned to CTA in comparison with 4602 patients randomly assigned to functional testing (33.4% versus 78.0%, and 0.9% versus 2.1%, respectively; both P<0.001). In CTA, 54.0% of events (n=74/137) occurred in patients with nonobstructive CAD (1%–69% stenosis). Prevalence of obstructive CAD and myocardial ischemia was low (11.9% versus 12.7%, respectively), with both findings having similar prognostic value (hazard ratio, 3.74; 95% confidence interval CI, 2.60–5.39; and 3.47; 95% CI, 2.42–4.99). When test findings were stratified as mildly, moderately, or severely abnormal, hazard ratios for events in comparison with normal tests increased proportionally for CTA (2.94, 7.67, 10.13; all P<0.001) but not for corresponding functional testing categories (0.94 P=0.87, 2.65 P=0.001, 3.88 P<0.001). The discriminatory ability of CTA in predicting events was significantly better than functional testing (c-index, 0.72; 95% CI, 0.68–0.76 versus 0.64; 95% CI, 0.59–0.69; P=0.04). If 2714 patients with at least an intermediate Framingham Risk Score (>10%) who had a normal functional test were reclassified as being mildly abnormal, the discriminatory capacity improved to 0.69 (95% CI, 0.64–0.74).
CONCLUSIONS:Coronary CTA, by identifying patients at risk because of nonobstructive CAD, provides better prognostic information than functional testing in contemporary patients who have stable chest pain with a low burden of obstructive CAD, myocardial ischemia, and events.
CLINICAL TRIAL REGISTRATION:URLhttp://www.clinicaltrials.gov. Unique identifierNCT01174550.
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