Comparison of Cardiorespiratory Fitness Prediction Equations and Generation of New Predictive Model for Patients with Obesity.

PURPOSE: Cardiorespiratory fitness (CRF) is a critical marker of overall health and a key predictor of morbidity and mortality, but the existing prediction equations for CRF are primarily derived from general populations and may not be suitable for patients with obesity. METHODS: Predicted CRF from different non-exercise prediction equations was compared with measured CRF of patients with obesity who underwent maximal cardiopulmonary exercise testing (CPET). Multiple linear regression was used to develop a population-specific non-exercise CRF prediction model for treadmill exercise including age, sex, weight, height and physical activity level as determinants. RESULTS: 660 patients underwent CPET during the study period. Within the entire cohort, R2 values had a range of 0.24-0.46. Predicted CRF was statistically different from measured CRF for 19 included equations. Only 50% of patients were correctly classified into the measured CRF categories according to predicted CRF. A multiple model for CRF prediction (ml/min) was generated (R2 = 0.78) and validated using two cross-validation methods. CONCLUSIONS: Most used equations provide inaccurate estimates of CRF in patients with obesity, particularly in cases of severe obesity and low CRF. Therefore, a new prediction equation was developed and validated specifically for patients with obesity, offering a more precise tool for clinical CPET interpretation and risk stratification in this population.

Serial cardiopulmonary exercise testing in young patients after one-and-half ventricle repair and Fontan procedure: a comparative study.

BACKGROUND: The Fontan procedure is the palliative surgical treatment for different congenital heart diseases (CHD) with a univentricular heart, but it has been associated with decreased exercise capacity, cardiovascular morbidity, and premature mortality. The one-and-half ventricle repair (1.5VR) was introduced as an alternative to the Fontan procedure, specifically for selected patients with borderline hypoplastic right ventricle (HRV), aiming for a more physiological circulation. Despite these efforts, the benefit of 1.5VR over Fontan circulation comparison on clinical and functional outcomes remains unclear. The aim of this study was to investigate and compare young patients with HRV after 1.5VR with those with functional single right or left ventricles (FSRV or FSLV) after Fontan palliation over a 10-year follow-up period. METHODS: In this retrospective observational study, serial cardiopulmonary exercise tests (CPETs) performed in patients with 1.5VR and Fontan circulation between September 2002 and March 2024 have been analyzed. Only patients with at least 10 years of follow-up were considered. RESULTS: A total of 41 patients were included (age at baseline 8.6 ± 2.6 years): 21 with FSLV, 12 with FSRV, and 10 with 1.5VR. No differences in cardiorespiratory fitness and efficiency were shown at the first CPET assessment among the three groups. At 10-year follow-up, 1.5VR had higher cardiorespiratory fitness and efficiency compared to FSLV and FSRV patients. CONCLUSIONS: These findings suggest that the 1.5VR may provide superior long-term functional outcomes than the Fontan procedure in patients with borderline HRV. Further studies are needed to evaluate the impact on hard clinical endpoints.

From surgery to functional capacity: muscle strength modifications in women post sleeve gastrectomy.

BACKGROUND: Severe obesity is characterized by excessive accumulation of fat generating a general health decline. Multidisciplinary treatment of obesity leads to significant weight loss in a few patients; therefore, many incur bariatric surgery. The main purpose of the study is to evaluate changes in functional capacity of people with obesity undergoing bariatric surgery and, in parallel, to correlate pre-surgery functional capacity with weight loss to improve exercise prescription during pre-operatory stage. METHODS: sixty women with diagnosed obesity were included. Maximal oxygen consumption, upper and lower limb strength and level of physical activity were recorded 1 month before and 6 months after sleeve gastrectomy. RESULTS: significant reduction on body weight (-30.1 kg) and Body Mass Index (-11.4 kg/m2) were highlighted after surgery. Absolute grip strength decreased significantly (-1.1 kg), while body weight normalized grip and lower limb strength increased significantly. The level of physical activity increased especially in leisure time (+ 593 METs/week) and active transport (+ 189.3 METs/week). Pre-surgery BMI and age predicted the amount of weight loss after surgery. CONCLUSIONS: Sleeve gastrectomy induces a reduction of muscle strength despite the increase of time spent in physical activity. Further research is necessary to integrate these results with data on body composition, and objective evaluation of physical activity level to define useful information for exercise prescription in terms of surgery pre-habilitation. TRIAL REGISTRATION: Padova University Hospital Board (protocol n. 2027 dated January 12, 2017).

Respiratory exchange ratio overshoot during exercise recovery: a promising prognostic marker in HFrEF.

BACKGROUND AND AIMS: Transient increases (overshoot) in respiratory gas analyses have been observed during exercise recovery, but their clinical significance is not clearly understood. An overshoot phenomenon of the respiratory exchange ratio (RER) is commonly observed during recovery from maximal cardiopulmonary exercise testing (CPET), but it has been found reduced in patients with heart failure with reduced ejection fraction (HFrEF). The aim of the study was to analyze the clinical significance of these RER recovery parameters and to understand if these may improve the risk stratification of patients with HFrEF. METHODS: This cross-sectional study includes HFrEF patients who underwent functional evaluation with maximal CPET for the heart transplant checklist at our Sports and Exercise Medicine Division. RER recovery parameters, including RER overshoot as the percentual increase of RER during recovery (RER mag), have been evaluated after CPET with assessment of hard clinical long-term endpoints (MACEs/deaths and transplant/LVAD-free survival). RESULTS: A total of 190 patients with HFrEF and 103 controls were included (54.6 ± 11.9 years; 73% male). RER recovery parameters were significantly lower in patients with HFrEF compared to healthy subjects (RER mag 24.8 ± 14.5% vs 31.4 ± 13.0%), and they showed significant correlations with prognostically relevant CPET parameters. Thirty-three patients with HFrEF did not present a RER overshoot, showing worse cardiorespiratory fitness and efficiency when compared with those patients who showed a detectable overshoot (VO2 peak: 11.0 ± 3.1 vs 15.9 ± 5.1 ml/kg/min; VE/VCO2 slope: 41.5 ± 8.7 vs 32.9 ± 7.9; ΔPETCO2: 2.75 ± 1.83 vs 4.45 ± 2.69 mmHg, respectively). The presence of RER overshoot was associated with a lower risk of cardiovascular events and longer transplant-free survival. CONCLUSION: RER overshoot represents a meaningful cardiorespiratory index to monitor during exercise gas exchange evaluation; it is an easily detectable parameter that could support clinicians to comprehensively interpreting patients' functional impairment and prognosis. CPET recovery analyses should be implemented in the clinical decision-making of advanced HF.

The Fragmented QRS Complex in Lead V1: Time for an Update of the Athlete's ECG?

Differentiating between ECG patterns related to athletes' heart remodeling and pathological findings is a challenge in sports cardiology. As the significance of fragmented complex in athletes remains uncertain, this study aimed to assess the presence of fragmented QRS in lead V1 (fQRSV1) among young athletes and its association with heart adaptations and arrhythmias. Young athletes referred for annual pre-participation screening receiving a maximal exercise testing and transthoracic echocardiography from January 2015 to March 2021 were included. The study included 684 young athletes. The prevalence of fQRSV1 was 33%. Subjects with fQRSV1 had higher exercise capacity and indexes of right ventricular function and remodeling. Among highly trained athletes, the fQRSV1 group demonstrated also increased left ventricular wall thickness. No significant association existed between fQRSV1 and exercise-induced arrhythmias, even in highly trained athletes. The high prevalence of fQRSV1 in young athletes is associated with training-induced heart adaptations but not exercise-induced ventricular arrhythmias.

The "Aging Effect" of BMI on Cardiorespiratory Fitness: A New Insight on Functional Evaluation in Obesity.

Cardiorespiratory fitness (CRF) is a strong predictor of morbidity and mortality in patients with obesity. This study investigates the CRF range and its clinical determinants in patients with obesity. Moreover, a practical proposal for CRF interpretation is provided. In this study, 542 patients (69% females) with BMI ≥ 30 kg/m2 performed an incremental cardiopulmonary exercise test (CPET). Patients had a median (IQR) age of 47.0 (6.2) years with a mean BMI of 41.7 ± 6.7 kg/m2. Normal values curves of VO2peak/kg showed a median (IQR) of 20.3 (37.6) mL/min/kg. The lower-quartile threshold of VO2peak/kg was at 17.9 mL/min/kg. Analysis of covariance revealed that VO2peak/kg inversely correlates with age and BMI with a significant age × BMI interaction effect (all p < 0.0001); as BMI class increases, CRF decreases, but a smaller age-related decline in VO2peak/kg is observed. A multivariate logistic regression demonstrated that belonging to the lower quartile of VO2peak/kg was independently determined by age (OR 2.549, 95% CI 1.205-5.392, p < 0.0001) and BMI (OR 5.864, 95% CI 2.920-11.778, p < 0.0001) but not by comorbidities. At very high BMI, the effect of age on functional capacity is lower, suggesting that BMI acts as an "aging factor" on CRF. Age and BMI, but not comorbidities, are independent determinants of low VO2peak/kg.

Down-staging of obesity one year after bariatric surgery: a new proposal of Edmonton obesity staging system.

Background: Different approaches are used to classify obesity severity. The Edmonton Obesity Staging System (EOSS) considers medical, physical and psychological parameters. A new modified EOSS with a different functional evaluation method, measuring Cardiorespiratory Fitness (CRF), has been recently proposed, EOSS-CRF. Bariatric surgery (BS) is one of the most efficient treatments of obesity and all aspect of related disorders. No studies have yet applied EOSS-CRF after BS. Therefore, the aim of this study was to evaluate modifications in EOSS and EOSS-CRF before and after BS. Methods: This observational study finally enrolled 72 patients affected by obesity. A multi-disciplinary assessment in order to evaluate eligibility to surgical treatment has been performed, including anamnesis, physical evaluation, anthropometric data measurement, biochemical blood exams and cardiopulmonary exercise testing. One year after BS the same protocol was applied. Patients have been classified according to EOSS and EOSS-CRF before and one year after BS. Results: After BS, patients categorized in classes associated to severe obesity (EOSS ≥ 2 or EOSS-CRF ≥ 2) reduced significantly. Using EOSS, patients without functional impairment were 61% before surgery and 69% after BS (p=0.383). Using EOSS-CRF, patients considered without functional impairment were only 9.7% before BS; this percentage significantly raised to 50% after BS (p<0.001). The impact of functional domains before and after BS is different in grading patients in EOSS and EOSS-CRF, respectively. Conclusions: Improvements obtained after BS are adequately summarized by EOSS and EOSS-CRF. The EOSS-CRF grading method for functional impairment seems to better reflect the known amelioration obtained after BS. Objective measurements of CRF may provide additional value to classify severity of obesity, also in the follow-up after BS.

Analysis of Walking Economy after Sleeve Gastrectomy in Patients with Severe Obesity.

BACKGROUND: Obesity is associated with a higher energy cost of walking which affects activities of daily living. Bariatric surgery with sleeve gastrectomy (SG) has beneficial effects on weight loss and comorbidities. PURPOSE: The aim of this study was to analyze the impact of SG on walking economy in subjects with severe obesity. METHODS: This observational cohort study included all patients with morbid obesity who were considered suitable candidates for SG between June 2017 and June 2019. Each patient underwent an incremental cardiopulmonary exercise test on a treadmill (modified Bruce protocol) one month before and six months after SG. Data on the energy cost of walking were recorded during three protocol stages (stage 0-slow flat walking: speed 2.7 km/h, slope 0%; stage ½-slow uphill walking: speed 2.7 km/h, slope 5%; stage 1-fast uphill walking: speed 4.0 km/h, slope 8%). RESULTS: 139 patients with morbid obesity (78% women; age 44.1 ± 10.7 years; BMI 42.5 ± 4.7 kg/m2) were included in the study. At six months post-SG, patients presented with a significantly decreased body weight (-30.5 ± 17.2 kg; p < 0.05), leading to an average BMI of 31.6 ± 4.2 kg/m2. The net energy cost of walking (measured in J/m and J/kg/m) of the subjects was lower compared to pre-SG at all three protocol stages. This improvement was also confirmed when the subjects were grouped by gender and obesity classes. CONCLUSION: After a significant weight loss induced by SG, regardless of the severity of obesity and gender, patients exhibited a lower energy expenditure and an improved walking economy. These changes make it easier to perform daily routines and may facilitate an increase in physical activity.

Overshoot of the Respiratory Exchange Ratio during Recovery from Maximal Exercise Testing in Young Patients with Congenital Heart Disease.

INTRODUCTION: The overshoot of the respiratory exchange ratio (RER) after exercise is reduced in patients with heart failure. AIM: The present study aimed to investigate the presence of this phenomenon in young patients with congenital heart disease (CHD), who generally present reduced cardiorespiratory fitness. METHODS: In this retrospective study, patients with CHD underwent a maximal cardiopulmonary exercise testing (CPET) assessing the RER recovery parameters: the RER at peak exercise, the maximum RER value reached during recovery, the magnitude of the RER overshoot and the linear slope of the RER increase after the end of the exercise. RESULTS: In total, 117 patients were included in this study. Of these, there were 24 healthy age-matched control subjects and 93 young patients with CHD (transposition of great arteries, Fontan procedure, aortic coarctation and tetralogy of Fallot). All patients presented a RER overshoot during recovery. Patients with CHD showed reduced aerobic capacity and cardiorespiratory efficiency during exercise, as well as a lower RER overshoot when compared to controls. RER magnitude was higher in the controls and patients with aortic coarctation when compared to those with transposition of great arteries, previous Fontan procedure, and tetralogy of Fallot. The RER magnitude was found to be correlated with the most relevant cardiorespiratory fitness and efficiency indices. CONCLUSIONS: The present study proposes new recovery indices for functional evaluation in patients with CHD. Thus, the RER recovery overshoots analysis should be part of routine CPET evaluation to further improve prognostic risk stratifications in patients with CHD.

The impact of the COVID-19 pandemic on functional capacity in a population of young athletes: should we expect long-time consequences?

BACKGROUND: From 2020, most countries all over the world have implemented strategies aimed at limiting contagion of COVID-19. The pandemic caused a reduction in physical activity (PA) and sports at all levels. The aim of the present study was to analyze and quantify the related impact of imposed PA restrictions on functional capacity in young athletes. METHODS: This observational cohort study evaluated annually the exercise capacity of a sample of young athletes (N.=344) referred for the pre-participation screening at our Sports and Exercise Medicine Division (2017-2021). Standardized maximal exercise testing was performed on treadmill and linear mixed models analyzed metabolic equivalent of tasks (METs) and exercise time as dependent variables. RESULTS: METs and exercise time showed a reduction in the year 2020 and a subsequent increase in 2021, with males revealing a faster recovery in exercise capacity. Athletes who maintained >250 annual training hours were less affected by the pandemic. CONCLUSIONS: These data suggest a significant impact of forced physical inactivity on a cohort of apparently healthy young athletes. The COVID-19-related experience should lead to strategies to avoid negative effects and long-term consequences of containment measures.

The incidence of cardiac arrhythmias during exercise stress testing: a focus on patients with severe obesity undergoing sleeve gastrectomy.

INTRODUCTION: Obesity is associated with a higher risk of cardiac arrhythmias. Sleeve gastrectomy (SG) is a common bariatric surgery with beneficial effects on weight loss and comorbidities. The study aimed to investigate the prevalence of arrhythmias during maximal exercise testing in patients with moderate-severe obesity and to evaluate the impact of SG on these arrhythmic events. METHODS: All patients with moderate or severe obesity who were considered suitable candidates for SG between June 2015 and September 2020 were recruited. Each patient underwent three incremental, maximal, ECG-monitored cardiopulmonary exercise test 1 month before and 6 and 12 months after SG; the frequency and complexity of ventricular premature beats (VPBs) and atrial premature beats (APBs) have been evaluated during rest, exercise and recovery phases. RESULTS: Fifty patients with severe obesity (BMI 46.39 ± 7.89 kg/m2) were included in the study. After SG, patients presented a decreased BMI (34.15 ± 6.25 kg/m2 at 6 months post-SG and 31.87 ± 5.99 kg/m2 at 12 months post-SG). At 6 months post-SG, an increase in VPBs, mainly during the recovery phase, was observed. At 12 months post-SG, a reduction in VPBs compared with the 6 months evaluation was showed. CONCLUSION: Although in the early post-surgical phase the risk of exercise-induced arrhythmias may be higher, SG does not seem to increase the occurrence of arrhythmias in the long-term. No life-threating arrhythmias were found during post-SG evaluations.

Can exercise test intensity and modality affect the prevalence of arrhythmic events in young athletes?

Pre-participation screening is performed to identify underlying cardiac conditions that may also lead to sudden cardiac death. Our aim is to compare submaximal Harvard Step Test (HST) with incremental Maximal Exercise Test (MET) on treadmill to induce and detect arrhythmias in younger athletes. A total of 1000 athletes (mean age 14.6 ± 4.7 years) were evaluated, 500 with MET and 500 with HST, all with continuous ECG monitoring until three minutes of recovery. Pre-test evaluation includes medical history, clinical evaluation and resting electrocardiogram. Ventricular and/or supraventricular arrhythmias were observed in 2.6% of athletes performing HST and in 8.4% during MET (p < 0.001). Incidence of arrhythmias remained higher for MET also considering separately exercise phase (0.8% vs. 5.2%; p < 0.001) and recovery phase (2.0% vs. 6.0%; p < 0.01). No gender differences were observed. Results suggest that MET induces more arrhythmias than submaximal HST, regardless of test phase. Higher test intensity and longer exercise duration might influence test outcomes, making MET more arrhythmogenic.

The Influence of Weight Loss in Postural Control in Women Undergoing Sleeve Gastrectomy.

BACKGROUND: Bariatric surgery is the most effective procedure for obesity management, with a greater body weight loss and the remission of several diseases. The aim of this study was to analyze the relationships between the anthropometric profile and postural control outcomes in a group of obese adult women, and the effect of bariatric surgery on postural control. METHODS: eighty-eight women candidates for bariatric surgery were recruited. Static balance was measured with the ARGO stabilometric platform under two conditions: open eyes (OE) and closed eyes (CE). RESULTS: Multiple linear regression indicated BMI as the first predictor for postural control in all parameters, except for APO in open eyes, predicted mainly by height. Changes in body weight and BMI showed no statistically significant correlations with modification of postural control parameters (OE), while they appeared to exert an influence under closed eyes conditions. CONCLUSIONS: Before surgery, obese patients with a higher BMI showed a better postural control. After surgery, the sway path and antero-posterior oscillation improved under open eyes conditions, while the magnitude of weight loss was negatively correlated with differences in postural control.

Do Androgenic Pattern, Insulin State and Growth Hormone Affect Cardiorespiratory Fitness and Strength in Young Women with PCOS?

In this study, cardiorespiratory fitness (CRF) and strength level were assessed in women with and without polycystic ovary syndrome (PCOS), matched for age, body composition, androgenic pattern and insulinemic pattern. Patients with and without PCOS were evaluated at the Endocrinology Unit and Sport Medicine Division to assess endocrinological (insulinemic, androgenic pattern and growth hormone), anthropometric (with DEXA) and functional parameters (with cardiopulmonary exercise test and handgrip test), as well as physical activity level (with the Global Physical Activity Questionnaire). A total of 31 patients with PCOS and 13 controls were included. No statistically significant differences were found between groups in terms of age, body mass index, body composition, androgenic pattern, insulin state, growth hormone and physical activity level. The PCOS group demonstrated significantly better cardiorespiratory fitness (VO2max per kg (30.9 ± 7.6 vs. 24.8 ± 4.1 mL/kg/min; p = 0.010), VO2max per kg of fat-free mass (52.4 ± 8.9 vs. 45.3 ± 6.2 mL/kg/min; p = 0.018)), strength levels (handgrip per kg (0.36 ± 0.09 vs. 0.30 ± 0.08; p = 0.009), handgrip per kg of fat-free mass (13.03 ± 2.32 vs. 11.50 ± 1.91; p = 0.001)) and exercise capacity (METs at test (14.4 ± 2.72 vs. 12.5 ± 1.72 METs; p = 0.019)). In this study, women with PCOS showed a better cardiorespiratory fitness and strength than the control group. The only determinant that could explain the differences observed seems to be the presence of the syndrome itself. These results suggest that PCOS per se does not limit exercise capacity and does not exclude good functional capacity.

Muscle strength, aerobic capacity, and exercise tolerance are impaired in left ventricular assist devices recipients: A pilot study.

Background: Left ventricular assist devices (LVAD) are increasingly being used as a therapy for advanced heart failure, both as a bridge to heart transplant and, given the rapid advances in the LVAD's functionality and safety, and constant lack in availability of donor organs, as long-term destination therapy. With the diffusion of such therapy, it is crucial to assess patients' muscle strength, aerobic capacity and exercise tolerance, to improve their functional capacity. Methods: 38 LVAD recipients (33 men and five women) were included. Exercise testing including a maximal cardiopulmonary exercise test (CPET), handgrip, isometric and isokinetic strength testing of knee and ankle flexion/extension, and Romberg balance test in three conditions (eyes open, eyes closed, double task). Given the small and heterogeneous final sample size, a mostly descriptive statistical approach was chosen. Results: 12 participants were classified as "Obese" (BMI>29.9). The most common comorbidities were type II diabetes and chronic kidney disease. Only 12 participants were able to successfully complete all the assessments. CPET and isokinetic strength trials were the least tolerated tests, and the handgrip test the best tolerated. Mean VO2 peak was 12.38 ± 3.43 ml/kg/min, with 15 participants below 50% of predicted VO2 max, of which 6 below 30% VO2max. Mean handgrip strength was 30.05 ± 10.61 Kg; 25 participants were below the 25° percentile of their population's normative reference values for handgrip strength, 10 of which were below the 5° percentile. Issues with the management of the external pack of the LVAD and its influence on the test limited the validity of the balance tests data, therefore, no solid conclusions could be drawn from them. VO2 peak did not correlate with handgrip strength or with any of the lower limb strength measures. Conclusion: LVAD recipients show greatly reduced functional capacity and tolerance to exercise and exercise testing, with low overall strength levels. As strength variables appear to be independent from VO2 peak, different lower limbs strength tests should be explored to find a tolerable alternative in this population, which is subjected to muscle wasting due to old age, reduced tissue perfusion, side effects from the pharmacological therapies, and prolonged periods of bedrest.

Exercise Capacity and Cardiorespiratory Fitness in Children with Congenital Heart Diseases: A Proposal for an Adapted NYHA Classification.

OBJECTIVE: To propose and evaluate an adapted NYHA classification for children with congenital heart disease (CHD) as a feasible clinical tool for classifying patients' fitness, cardiorespiratory efficiency and functional limitations during their ordinary daily activities, which are also characterized by vigorous and competitive physical exercise among peers. METHODS: This cross-sectional investigation analyzed 332 patients (13.1 ± 3.01 y/o) who underwent surgical repair of CHD and performed Cardiopulmonary Exercise Testing (CPET). Patients were divided into NYHA class I, IIA and IIB by specific questioning regarding functional limitation and performance compared to peers and at strenuous intensity. Class IIA was characterized by slight exercise limitation only for strenuous/competitive activities, whereas IIB for already ordinary physical activities. These NYHA classes were compared with maximal CPET on treadmill. RESULTS: Patients' exercise capacity (exercise time, METs), aerobic capacity (VO2peak) and chronotropic response were found progressively impaired when NYHA class I was compared with IIA and IIB. Indeed, ventilatory-perfusion mismatch (PETCO2, VE/VCO2) significantly worsened from NYHA class I to IIA, while no difference was found between IIA and IIB. CONCLUSION: This adapted NYHA-CHD classification could allow regular functional evaluations and accurate assessments by clinicians, leading to facilitated clinical management and timely medical interventions.

Cardiopulmonary exercise testing in patients with moderate-severe obesity: a clinical evaluation tool for OSA?

PURPOSE: Obstructive sleep apnea (OSA) is a widespread comorbidity of obesity. Nasal continuous positive airway pressure (CPAP) has been demonstrated very effective in treating patients with OSA. The aims of this study were to investigate whether or not cardiopulmonary exercise testing (CPET) can characterize patients with OSA and to evaluate the effect of nasal CPAP therapy. METHODS: An observational study was conducted on patients with moderate to severe obesity and suspected OSA. All patients underwent cardiorespiratory sleep study, spirometry, and functional evaluation with ECG-monitored, incremental, maximal CPET. RESULTS: Of the 147 patients, 94 presented with an apnea-hypopnea index (AHI) ≥ 15 events/h and were thus considered to have OSA (52 receiving nasal CPAP treatment; 42 untreated) while 53 formed a control group (AHI < 15 events/h). Patients with untreated OSA showed significantly lower oxygen uptake (VO2), heart rate, minute ventilation (VE), and end tidal carbon dioxide (PETCO2) at peak exercise compared to controls. Patients receiving nasal CPAP showed higher VE and VO2 at peak exercise compared to untreated patients. A difference in PETCO2 between the maximum value reached during test and peak exercise (ΔPETCO2 max-peak) of 1.71 mmHg was identified as a predictor of OSA. CONCLUSION: Patients with moderate to severe obesity and untreated OSA presented a distinctive CPET-pattern characterized by lower aerobic and exercise capacity, higher PETCO2 at peak exercise associated with a lower ventilatory response. Nasal CPAP treatment was shown to positively affect these cardiorespiratory adaptations during exercise. ΔPETCO2 max-peak may be used to suggest OSA in patients with obesity.

Overshoot of the Respiratory Exchange Ratio during Recovery from Maximal Exercise Testing in Kidney Transplant Recipients.

The overshoot of the respiratory exchange ratio (RER) during recovery from exercise has been found to be reduced in magnitude among patients with heart failure. The aim of this study is to investigate whether this phenomenon could also be present in patients with peripheral, and not cardiac, limitations to exercise such as kidney transplant recipients (KTRs). In this retrospective cross-sectional study, KTRs were evaluated with maximal cardiopulmonary exercise testing (CPET) assessing the RER overshoot parameters during recovery: the RER at peak exercise, the maximum RER value reached during recovery, the magnitude of the RER overshoot (RER mag = (RER max-peak RER)/peak RER%) and the linear slope of the RER increase after the end of exercise. A total of 57 KTRs were included in the study (16 females), all of them showing a significant RER overshoot (RER mag: 28.4 ± 12.7%). Moreover, the RER mag showed significant correlations with the fitness of patients (peak VO2: ρ = 0.57, p < 0.01) and cardiorespiratory efficiency (VE/VCO2 slope: r = -0.32, p < 0.05; oxygen uptake efficiency slope (OUES): r = 0.48, p < 0.01). Indeed, the RER mag was significantly different between the subgroups stratified by Weber's fitness class or a ventilatory efficiency class. Our study is the first to investigate recovery of the RER in a population of KTRs, which correlates well with known prognostic CPET markers of cardiorespiratory fitness, determining the RER mag as the most meaningful RER overshoot parameter. Thus, the RER recovery might be included in CPET evaluations to further improve prognostic risk stratifications in KTRs and other chronic diseases.

Metabolic Response to Submaximal and Maximal Exercise in People with Severe Obesity, Prediabetes, and Diabetes.

INTRODUCTION: Metabolic adaptations to maximal physical exercise in people with obesity (PwO) are scarcely described. This cross-sectional study evaluates the metabolic response to exercise via the respiratory exchange ratio (RER) in PwO and different degrees of glycemic control. METHODS: Eighty-five PwO (body mass index 46.0 [39.0-54.0] kg/m2), that is, 32 normoglycemic (Ob-N), 25 prediabetic (Ob-preDM), and 28 diabetic (Ob-T2DM) subjects and 18 healthy subjects performed an incremental, maximal cardiopulmonary exercise test. The RER was measured at rest (RERrest) and at peak exercise (RERpeak). RESULTS: RERpeak was significantly higher in healthy subjects than that in PwO. Among those, RERpeak was significantly higher in Ob-N than that in Ob-preDM and Ob-T2DM (1.20 [1.15-1.27] vs. 1.18 [1.10-1.22] p = 0.04 and vs. 1.14 [1.10-1.18] p < 0.001, respectively). Accordingly, ΔRER (RERpeak-RERrest) was lower in Ob-preDM and Ob-T2DM than that in Ob-N (0.32 [0.26-0.39] p = 0.04 and 0.29 [0.24-0.36] p < 0.001 vs. 0.38 [0.32-0.43], respectively), while no significant difference was found in ΔRER between Ob-preDM and Ob-T2DM and not even between Ob-N and healthy subjects. Moreover, ΔRER in PwO correlated with glucose area under curve (p = 0.002). CONCLUSIONS: PwO demonstrate restricted metabolic response during maximal exercise. Particularly, those with prediabetes already show metabolic inflexibility during exercise, similarly to those with type 2 diabetes. These findings also suggest a potential role of cardiopulmonary exercise testing in detecting early metabolic alterations in PwO.