Cardiopulmonary exercise testing: relevant but underused

Cardiopulmonary Exercise Testing in a Prospective Multicenter Cohort of Older Adults

PURPOSE

Cardiorespiratory fitness (CRF) measured by peak oxygen consumption (V̇O 2peak ) declines with aging and correlates with mortality and morbidity. Cardiopulmonary exercise testing (CPET) is the criterion method to assess CRF, but its feasibility, validity, and reliability in older adults are unclear. Our objective was to design and implement a dependable, safe, and reliable CPET protocol in older adults.

METHODS

V̇O 2peak was measured by CPET, performed using treadmill exercise in 875 adults ≥70 yr in the Study of Muscle, Mobility and Aging (SOMMA). The protocol included a symptom-limited peak (maximal) exercise and two submaximal walking speeds. An adjudication process was in place to review tests for validity if they met any prespecified criteria (V̇O 2peak <12.0 mL·kg -1 ·min -1 ; maximum heart rate <100 bpm; respiratory exchange ratio <1.05 and a rating of perceived exertion <15). A subset ( N = 30) performed a repeat test to assess reproducibility.

RESULTS

CPET was safe and well tolerated, with 95.8% of participants able to complete the V̇O 2peak phase of the protocol. Only 56 (6.4%) participants had a risk alert and only two adverse events occurred: a fall and atrial fibrillation. Mean ± SD V̇O 2peak was 20.2 ± 4.8 mL·kg -1 ·min -1 , peak heart rate 142 ± 18 bpm, and peak respiratory exchange ratio 1.14 ± 0.09. Adjudication was indicated in 47 tests; 20 were evaluated as valid and 27 as invalid (18 data collection errors, 9 did not reach V̇O 2peak ). Reproducibility of V̇O 2peak was high (intraclass correlation coefficient = 0.97).

CONCLUSIONS

CPET was feasible, effective, and safe for older adults, including many with multimorbidity or frailty. These data support a broader implementation of CPET to provide insight into the role of CRF and its underlying determinants of aging and age-related conditions.

Clinimetric Properties of the Steep Ramp Test to Assess Cardiorespiratory Fitness, Its Underlying Physiological Responses, and Its Current Applications: A Scoping Review

OBJECTIVE

Providing an overview of the clinimetric properties of the steep ramp test (SRT)-a short-term maximal exercise test-to assess cardiorespiratory fitness (CRF), describing its underlying physiological responses, and summarizing its applications in current clinical and research practice.

DATA SOURCES

MEDLINE (through PubMed), CINAHL Complete, Cochrane Library, EMBASE, and PsycINFO were searched for studies published up to July 2023, using keywords for SRT and CRF.

STUDY SELECTION

Eligible studies involved the SRT as research subject or measurement instrument and were available as full text articles in English or Dutch.

DATA EXTRACTION

Two independent assessors performed data extraction. Data addressing clinimetric properties, physiological responses, and applications of the SRT were tabulated.

DATA SYNTHESIS

In total, 370 studies were found, of which 39 were included in this study. In several healthy and patient populations, correlation coefficients between the work rate at peak exercise (WRpeak) attained at the SRT and oxygen uptake at peak exercise during cardiopulmonary exercise testing (CPET) ranged from .771-.958 (criterion validity). Repeated measurements showed intraclass correlation coefficients ranging from .908-.996 for WRpeak attained with the first and second SRT (test-retest reliability). Physiological parameters, like heart rate and minute ventilation at peak exercise, indicated that the SRT puts a lower burden on the cardiopulmonary system compared to CPET. The SRT is mostly used to assess CRF, among others as part of preoperative risk assessment, and to personalize interval training intensity.

CONCLUSIONS

The SRT is a practical short-term maximal exercise test that is valid for CRF assessment and to monitor changes in CRF over time in various healthy and patient populations. Its clinimetric properties and potential applications make the SRT of interest for a widespread implementation of CRF assessment in clinical and research practice and for personalizing training intensity and monitoring longitudinal changes in CRF.

Revisiting the clinical utilization of cardiopulmonary exercise testing in Saudi Arabia after 2 decades: A cross-sectional study

OBJECTIVES

To assess the prevalence of cardiopulmonary exercise testing (CPET) usage and identify barriers among major hospitals and medical centers in Saudi Arabia. We also aim to compare these findings with data from nearly 2 decades ago.

METHODS

In this cross-sectional study, 70 major hospitals and medical centers were contacted, and 52 (74.2%) responded. The participants involved in this study were healthcare providers proficient in carrying out CPET from different specialties. The survey comprised 21 items covering CPET utilization, exercise mode characteristics, common protocols, types of patients or disorders, and barriers to not carrying out CPET.

RESULTS

The majority (n=37; 71.9%) of the centers reported a lack of CPET utilization. Of the 15 centers that used CPET, only 11 carried out regular CPET. Cardiac-related conditions were the most commonly referred clinical cases (n=7), followed by pulmonary conditions and cardiopulmonary fitness. The common barriers to carrying out CPET have remained unchanged compared to 2 decades ago - that is, the lack of equipment or trained technicians. However, there has been a 14.1% increase in the utilization of CPET and a 10.1% increase in the use of treadmill mode compared to a survey carried out 2 decades ago.

CONCLUSION

Although CPET utilization has increased over 2 decades, this still falls below the desired benchmark. This highlights the need for collaborative efforts among policymakers, and healthcare institutions to address barriers and improve CPET integration into clinical practice.

Surveillance cardiopulmonary exercise testing can risk-stratify childhood cancer survivors: underlying pathophysiology of poor exercise performance and possible room for improvement

BACKGROUND

Asymptomatic childhood cancer survivors (CCS) frequently show decreased exercise performance. Poor exercise performance may indicate impaired future cardiovascular health.

METHODS

Cardiopulmonary exercise testing (CPET) was performed in asymptomatic off-treatment CCS (age ≥ 10 years). Patients were divided into Normal and Poor performance groups by %predicted maximum VO2 at 80%. Both peak and submaximal CPET values were analyzed.

RESULTS

Thirty-eight males (19 Normal, 19 Poor) and 40 females (18 Normal, 22 Poor) were studied. Total anthracycline dosage was comparable among 4 groups. The body mass index (BMI), although normal, and weight were significantly higher in Poor groups. Peak heart rate (HR) and peak respiratory exchange ratio (RER) were comparable in all four groups. Peak work rate (pWR)/kg, peak oxygen consumption (pVO2)/kg, peak oxygen pulse (pOP)/kg, and ventilatory anaerobic threshold (VAT)/kg were significantly lower, whereas heart rate (HR) increase by WR/kg (ΔHR/Δ[WR/kg] was significantly higher in Poor groups. Simultaneously plotting of weight & pVO2 and ΔHR/ΔWR & ΔVO2/ΔHR revealed a distinct difference between the Normal and Poor groups in both sexes, suggesting decreased skeletal muscle mass and decreased stroke volume reserve, respectively, in Poor CCS. The relationship between VAT and pVO2 was almost identical between the two groups in both sexes. Ventilatory efficiency was mildly diminished in the Poor groups.

CONCLUSIONS

Decreased skeletal muscle mass, decreased stroke volume reserve, and slightly decreased ventilatory efficiency characterize Poor CCS in both sexes. This unique combined CPET analysis provides useful clinical biomarkers to screen subclinical cardiovascular abnormality in CCS and identifies an area for improvement.

Cardiopulmonary Exercise Testing in Heart Failure With Preserved Ejection Fraction: Technique Principles, Current Evidence, and Future Perspectives

Heart failure with preserved ejection fraction (HFpEF) is a multifactorial clinical syndrome involving a rather complex pathophysiologic substrate and quite a challenging diagnosis. Exercise intolerance is a major feature of HFpEF, and in many cases, diagnosis is suspected in subjects presenting with exertional dyspnea. Cardiopulmonary exercise testing (CPET) is a noninvasive, dynamic technique that provides an integrative evaluation of cardiovascular, pulmonary, hematopoietic, neuropsychological, and metabolic functions during maximal or submaximal exercise. The assessment is based on the principle that system failure typically occurs when the system is under stress, and thus, CPET is currently considered to be the gold standard for identifying exercise intolerance, allowing the differential diagnosis of underlying causes. CPET is used in observational studies and clinical trials in HFpEF; however, in most cases, only a few from a wide variety of CPET parameters are examined, while the technique is largely underused in everyday cardiology practice. This article discusses the basic principles and methodology of CPET and studies that utilized CPET in patients with HFpEF, in an effort to increase awareness of CPET capabilities among practicing cardiologists.

Cardiopulmonary Exercise Testing in a Prospective Multicenter Cohort of Older Adults: The Study of Muscle, Mobility and Aging (SOMMA)

BACKGROUND

Cardiorespiratory fitness (CRF) measured by peak oxygen consumption (VO2peak) declines with aging and correlates with mortality and morbidity. Cardiopulmonary Exercise Testing (CPET) has long been the criterion method to assess CRF, but its feasibility, efficacy and reliability in older adults is unclear. The large, multicenter Study of Muscle, Mobility and Aging (SOMMA) employed CPET to evaluate the mechanisms underlying declines in mobility with aging among community-dwelling older adults. Our primary objective was to design and implement a CPET protocol in older adults that was dependable, safe, scientifically valuable, and methodologically reliable.

METHODS

CPET was performed using treadmill exercise in 875 adults ≥70 years. A composite protocol included a symptom-limited peak exercise phase and two submaximal phases to assess cardiopulmonary ventilatory indices during 1) participants' preferred walking speed and 2) at slow walking speed of 1.5 mph (0.67 m/s). An adjudication process was in place to review tests for validity if they met any prespecified criteria (VO2peak <12.0 ml/kg/min; maximum heart rate (HR) <100 bpm; respiratory exchange ratio (RER) <1.05 and a rating of perceived exertion <15). A repeat test was performed in a subset (N=30) to assess reproducibility.

RESULTS

CPET was safe and well tolerated, with 95.8% of participants able to complete the VO2peak phase of the protocol. Only 56 (6.4%) participants had a risk alert during any phase of testing and only two adverse events occurred during the peak phase: a fall and atrial fibrillation. The average ± standard deviation for VO2peak was 20.2 ± 4.8 mL/kg/min, peak HR 142 ± 18 bpm, and peak RER 1.14 ± 0.09. VO2peak and RER were slightly higher in men than women. Adjudication was indicated in 47 participants; 20 were evaluated as valid, 27 as invalid (18 had a data collection error, 9 did not reach VO2peak). Reproducibility of VO2peak was high (intraclass correlation coefficient=0.97).

CONCLUSIONS

CPET was feasible, effective and safe for community-dwelling older adults, many of whom had multimorbidity and frailty. These data support a broader implementation of CPET to provide important insight into the role of CRF and its underlying determinants in aging and age-related conditions and diseases.

Clinical Perspective

What Is New?: Performing cardiopulmonary exercise testing in a community dwelling older adult with multimorbidities or frailty is feasible and exceptionally safe under highly trained exercise physiologists and physician supervision.Reproducibility of VO2peak among community-dwelling older adults with significant clinical complexity was high (intraclass correlation coefficient=0.97).The VO2peak observed was comparable to established normative data for older adults, and adds merit to the limited data collected on VO2peak norms in older adults.What Are the Clinical Implications?: Ventilatory gas collection during clinical cardiac stress testing may be valuable to plan of care in routine management of older adults due to the important role of aerobic fitness on morbidity and mortality.Cardiopulmonary exercise testing can provide insight into the role of cardiorespiratory fitness and its underlying determinants in aging and age-related conditions and diseases.

A Simple Equation to Estimate Maximal Oxygen Uptake in Older Adults Using the 6 min Walk Test, Sex, Age and Body Mass Index

PURPOSE

The 6 min walk test (6MWT) is used in clinical and epidemiological practice as a simple tool to evaluate the maximal aerobic exercise capacity (VO2max). To date, little evidence has been provided regarding regression equation models to predict VO2max in older adults. Therefore, the main purpose of the study was to develop a reference equation to estimate objectively measured VO2max, based on the 6MWT, sex, age and body mass index (BMI).

PATIENTS AND METHODS

In this observational prospective study, we collected the data from 233 asymptomatic participants aged 60-80 years (52.4% women). VO2max and the 6MWT were measured using standardized protocols. BMI was calculated as weight (kg) divided by height squared (m2). To be able to develop the predictive equation for VO2max, we used linear generalized estimating equations (GEE).

RESULTS

Older men performed better in VO2max (30.9 ± 8.8 vs. 26.3 ± 6.3 mL/kg/min, p < 0.001) and the 6MWT (673.9 ± 58.7 vs. 642.3 ± 48.0 m, p < 0.001), compared to women. VO2max was correlated with the 6MWT (r = 0.71, p < 0.001), sex (r = -0.29, p < 0.001), age (r = -0.62, p < 0.001) and BMI (r = -0.38, p < 0.001). The model to predict VO2max included: VO2max (mL/kg/min) = 59.44 - 3.83 *, sex (1-men; 2-women) - 0.56 *, age (years) - 0.48 *, BMI (kg/m2) + 0.04 *, and the 6MWT (m) (R = 0.85; R2 = 72.3%, SEE = 3.99 mL/kg/min, p < 0.001).

CONCLUSION

The newly developed regression equation can be a guideline in clinical and epidemiological practice to predict the VO2max in apparently healthy older adults.

Cardiopulmonary fitness in children with asthma versus healthy children

OBJECTIVES

To evaluate, with a cardiopulmonary exercise test (CPET), the cardiopulmonary fitness of children with asthma, in comparison to healthy controls, and to identify the clinical and CPET parameters associated with the maximum oxygen uptake (VO_2max) in childhood asthma.

DESIGN

This cross-sectional controlled study was carried out in CPET laboratories from two tertiary care paediatric centres. The predictors of VO_2max were determined using a multivariable analysis.

RESULTS

A total of 446 children (144 in the asthma group and 302 healthy subjects) underwent a complete CPET. Mean VO_2max was significantly lower in children with asthma than in controls (38.6±8.6 vs 43.5±7.5 mL/kg/min; absolute difference (abs. diff.) of -4.9 mL/kg/min; 95% CI of (-6.5 to -3.3) mL/kg/min; p<0.01) and represented 94%±9% and 107%±17% of predicted values, respectively (abs. diff. -13%; 95% CI (-17 to -9)%; p<0.01). The proportion of children with an impaired VO_2max was four times higher in the asthma group (24% vs 6%, p<0.01). Impaired ventilatory efficiency with increased VE/VCO₂ slope and low breathing reserve (BR) were more marked in the asthma group. The proportion of children with a decreased ventilatory anaerobic threshold (VAT), indicative of physical deconditioning, was three times higher in the asthma group (31% vs 11%, p<0.01). Impaired VO_2max was associated with female gender, high body mass index (BMI), FEV1, low VAT and high BR.

CONCLUSION

Cardiopulmonary fitness in children with asthma was moderately but significantly altered compared with healthy children. A decreased VO_2max was associated with female gender, high BMI and the pulmonary function.

TRIAL REGISTRATION NUMBER

NCT04650464.

Comprehensive cardiopulmonary profile of individuals with Down syndrome

BACKGROUND

Individuals with Down syndrome (DS) have low levels of cardiorespiratory fitness and previous studies have shown that these low levels of fitness have a physiological cause. During exercise, the cardiovascular, ventilatory and muscular systems are simultaneously active. While individual parameters of these systems have been investigated in DS before, the interaction between these parameters and systems have not been discussed in detail. Doing so may provide important insight regarding the aetiology of low cardiorespiratory fitness and which parameters of the cardiovascular, pulmonary and muscular systems are altered in individuals with DS compared with their peers without DS.

METHODS

Cardiopulmonary exercise tests were performed in healthy adults with and without DS. Parameters related to the cardiovascular, ventilatory and muscular systems were collected until VO_2peak . In total, 51 participants were included in analysis, of which 21 had DS.

RESULTS

Individuals with DS showed lower peak values for all collected outcomes (P ≤ 0.001) compared with those without DS, except for ventilatory threshold as a percentage of maximal oxygen uptake and V_E /VCO₂ slope, which were similar.

CONCLUSIONS

Our results show that individuals with DS present impairments across the cardiovascular, ventilatory and muscular aspects of the cardiopulmonary system.

Effects of an active lifestyle on the physical frailty of liver transplant candidates

BACKGROUND

Liver transplantation is the most important therapeutic intervention for end-stage liver disease (ELD). The prioritization of these patients is based on the model for end-stage liver disease (MELD), which can successfully predict short-term mortality. However, despite its great validity and value, it cannot fully incorporate several comorbidities of liver disease, such as sarcopenia and physical frailty, variables that can sufficiently influence the survival of such patients. Subsequently, there is growing interest in the importance of physical frailty in regard to mortality in liver transplant candidates and recipients, as well as its role in improving their survival rates.

AIM

To evaluate the effects of an active lifestyle on physical frailty on liver transplant candidates.

METHODS

An observational study was performed within the facilities of the Department of Transplant Surgery of Aristotle University of Thessaloniki. Twenty liver transplant candidate patients from the waiting list of the department were included in the study. Patients that were bedridden, had recent cardiovascular incidents, or had required inpatient treatment for more than 5 d in the last 6 mo were excluded from the study. The following variables were evaluated: Activity level via the International Physical Activity Questionnaire (IPAQ); functional capacity via the 6-min walking test (6MWT) and cardiopulmonary exercise testing; and physical frailty via the Liver Frailty Index (LFI).

RESULTS

According to their responses in the IPAQ, patients were divided into the following two groups based on their activity level: Active group (A, 10 patients); and sedentary group (S, 10 patients). Comparing mean values of the recorded variables showed the following results: MELD (A: 12.05 ± 5.63 vs S: 13.99 ± 3.60; P > 0.05); peak oxygen uptake (A: 29.78 ± 6.07 mL/kg/min vs S: 18.11 ± 3.39 mL/kg/min; P < 0.001); anaerobic threshold (A: 16.71 ± 2.17 mL/kg/min vs S: 13.96 ± 1.45 mL/kg/min; P < 0.01); 6MWT (A: 458.2 ± 57.5 m vs S: 324.7 ± 55.8 m; P < 0.001); and LFI (A: 3.75 ± 0.31 vs S: 4.42 ± 0.32; P < 0.001).

CONCLUSION

An active lifestyle can be associated with better musculoskeletal and functional capacity, while simultaneously preventing the evolution of physical frailty in liver transplant candidates. This effect appears to be independent of the liver disease severity.

Age-Related Differences for Cardiorespiratory Fitness Improvement in Patients Undergoing Cardiac Rehabilitation

Objective

We investigated age-related differences for peak oxygen uptake (peak VO₂) improvement with exercise training during cardiac rehabilitation (CR).

Patients and Methods

This was a retrospective cohort study of the Mayo Clinic Rochester CR program including adult patients who attended CR (≥1 session) for any eligible indication between 1999 and 2017 and who had a cardiopulmonary exercise test pre and post CR with VO₂ data (peak respiratory exchange ratio ≥1.0). Younger (20–49 yrs), midlife (50–64 yrs), and older adults (≥65 yrs) were compared using ANOVA for delta and percent change in peak VO₂; and percentage of peak VO₂ responders (>0% change).

Results

708 patients (age: 60.8 ± 12.1 years; 24% female) met inclusion criteria. Delta and percent change in peak VO₂ was lower for older adults (1.6 ± 3.2 mL.kg.min⁻¹; 12 ± 27%) compared with younger (3.7 ± 4.0 mL.kg.min⁻¹, p < 0.001; 23 ± 28%, p = 0.002) and midlife adults (2.8 ± 3.8 mL.kg.min⁻¹, p < 0.001; 17 ± 28%, p = 0.04). For midlife, delta change, but not percent change in peak VO₂ was significantly lower (p = 0.02) compared with younger. Percentage of responders was only different between older and younger (72 vs. 86%; p = 0.008). Sensitivity analyses in non-surgical patients showed similar differences for delta change, and differences in percent change remained significant between older and younger adults (10 ± 20% vs. 16 ± 18%; p = 0.04).

Conclusions

In CR patients, older adults had lower improvement in cardiorespiratory fitness than younger and midlife adults. While excluding surgical patients reduced age-related differences, older adults still had lower cardiorespiratory fitness improvement during CR. These findings may have implications for individualizing CR programming in aging populations to reduce future cardiovascular risk.

Effects of bariatric surgery on cardiorespiratory fitness: A systematic review and meta-analysis

Although bariatric surgery (BS) is recognized as an effective strategy for body weight loss, its impact on cardiorespiratory fitness (CRF) is still unclear. We aimed to examine postoperative changes in CRF (VO_2max/peak ) and its relationship with weight loss among adults undergoing BS. We systematically searched the WoS, PubMed, MEDLINE, and Scopus databases. Observational and intervention studies were selected reporting the presurgery and postsurgery CRF, measured by breath-by-breath VO₂ or its estimation. Eleven articles (312 patients) revealed that BS leads to a reduction in absolute VO_2max/peak in the short term (effect size, ES = -0.539; 95%CI = -0.708, -0.369; p < 0.001), and those patients who suffered a more significant decrease in BMI after BS also had a greater loss of absolute VO_2max/peak . However, VO_2max/peak relative to body weight increased after surgery (ES = 0.658; 95%CI = 0.473, 0.842; p < 0.001). An insufficient number of studies were found investigating medium and long-term changes in CRF after BS. This study provides moderate-quality evidence that the weight loss induced by BS can reduce CRF in the short term, which represents a therapeutic target to optimize BS outcomes. More high-quality studies are needed to evaluate the impact of BS on VO_2max/peak in the short, medium, and long term including normalized values for fat-free mass.

ARTP statement on cardiopulmonary exercise testing 2021

Cardiopulmonary exercise testing (CPET) has become an invaluable tool in healthcare, improving the diagnosis of disease and the quality, efficacy, assessment and safety of treatment across a range of pathologies. CPET's superior ability to measure the global exercise response of the respiratory, cardiovascular and skeletal muscle systems simultaneously in a time and cost-efficient manner has led to the application of CPET in a range of settings from diagnosis of disease to preoperative assessment. The Association for Respiratory Technology and Physiology Statement on Cardiopulmonary Exercise Testing 2021 provides the practitioner and scientist with an outstanding resource to support and enhance practice, from equipment to testing to leadership, helping them deliver a quality assured service for the benefit of all patient groups.

Obesity Blunts the Ventilatory Response to Exercise in Men and Women

Rationale: Obesity presents a mechanical load to the thorax, which could perturb the generation of minute ventilation (V̇e) during exercise. Because the respiratory effects of obesity are not homogenous among all individuals with obesity and obesity-related effects could vary depending on the magnitude of obesity, we hypothesized that the exercise ventilatory response (slope of the V̇e and carbon dioxide elimination [V̇co₂] relationship) would manifest itself differently as the magnitude of obesity increases.Objectives: To investigate the V̇e/V̇co₂ slope in an obese population that spanned across a wide body mass index (BMI) range.Methods: A total of 533 patients who presented to a surgical weight loss center for pre-bariatric surgery testing performed an incremental maximal cycling test and were studied retrospectively. The V̇e/V̇co₂ slope was calculated up to the ventilatory threshold. Patients were examined in groups based on BMI (category 1: 30-39.9 kg/m², category 2: 40-49.9 kg/m², and category 3: ≥50 kg/m²). Because the respiratory effects of obesity could be sex and/or age specific, we further examined patients in groups by sex and age (younger: <50 yr and older: ≥50 yr). Differences in the V̇e/V̇co₂ slope were then compared between BMI category, age, and sex using a three-way ANOVA.Results: No significant BMI category by sex by age interactions was detected (P = 0.75). The V̇e/V̇co₂ slope decreased with increases in BMI (category 1, 29.1 ± 4.0; category 2, 28.4 ± 4.1; and category 3, 27.1 ± 3.3) and was elevated in women (28.9 ± 4.1) compared with men (26.7 ± 3.2) (BMI category by sex interaction, P < 0.05). No age-related differences were observed (BMI category by age interaction, P = 0.55). The partial pressure for end-tidal CO₂ was elevated at the ventilatory threshold in BMI category 3 compared with BMI categories 1 and 2 (both P < 0.01).Conclusions: These findings suggest that obesity presents a unique challenge to augmenting ventilatory output relative to CO₂ elimination, such that the increase in the exercise ventilatory response becomes blunted as the magnitude of obesity increases. Further studies are required to investigate the clinical consequences and the mechanisms that may explain the attenuation of exercise ventilatory response with increasing BMI in men and women with obesity.

Development of a New Submaximal Walk Test to Predict Maximal Oxygen Consumption in Healthy Adults

The aim of the study was to develop a simple submaximal walk test protocol and equation using heart rate (HR) response variables to predict maximal oxygen consumption (VO2max). A total of 60 healthy adults were recruited to test the validity of 3 min walk tests (3MWT). VO2max and HR responses during the 3MWTs were measured. Multiple regression analysis was used to develop prediction equations. As a result, HR response variables including resting HR and HR during walking and recovery at two different cadences were significantly correlated with VO2max. The equations developed using multiple regression analyses were able to predict VO2max values (r = 0.75-0.84; r2 = 0.57-0.70; standard error of estimate (SEE) = 4.80-5.25 mL/kg/min). The equation that predicted VO2max the best was at the cadence of 120 steps per minute, which included sex; age; height; weight; body mass index; resting HR; HR at 1 min, 2 min and 3 min; HR recovery at 1 min and 2 min; and other HR variables calculated based on these measured HR variables (r = 0.84; r2 = 0.70; SEE = 4.80 mL/kg/min). In conclusion, the 3MWT developed in this study is a safe and practical submaximal exercise protocol for healthy adults to predict VO2max accurately, even compared to the well-established submaximal exercise protocols, and merits further investigation.

Safety and feasibility of symptom-limited cardiopulmonary exercise test using the modified Naughton protocol in children with cerebral palsy: An observational study

ABSTRACT

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.

Evidence of a double anaerobic threshold in healthy subjects

AIMS

The anaerobic threshold (AT) is an important cardiopulmonary exercise test (CPET) parameter both in healthy and in patients. It is normally determined with three approaches: V-slope method, ventilatory equivalent method, and end-tidal method. The finding of different AT values with these methods is only anecdotic. We defined the presence of a double threshold (DT) when a ΔVO2 > 15 mL/min was observed between the V-slope method (met AT) and the other two methods (vent AT). The aim was to identify whether there is a DT in healthy subjects.

METHODS AND RESULTS

We retrospectively analysed 476 healthy subjects who performed CPET in our laboratory between 2009 and 2018. We identified 51 subjects with a DT (11% of cases). Cardiopulmonary exercise test data at rest and during the exercise were not different in subjects with DT compared to those without. Met AT always preceded vent AT. Compared to subjects without DT, those with DT showed at met AT lower carbon dioxide output (VCO2), end-tidal carbon dioxide tension (PetCO2) and respiratory exchange ratio (RER), and higher ventilatory equivalent for carbon dioxide (VE/VCO2). Compared to met AT, vent AT showed a higher oxygen uptake (VO2), VCO2, ventilation, respiratory rate, RER, work rate, and PetCO2 but a lower VE/VCO2 and end-tidal oxygen tension. Finally, subjects with DT showed a higher VO2 increase during the isocapnic buffering period.

CONCLUSION

Double threshold was present in healthy subjects. The presence of DT does not influence peak exercise performance, but it is associated with a delayed before acidosis-induced hyperventilation.

Survey of Clinician Perspectives and Practices Regarding Swallowing-Related Fatigue

Introduction Fatigue is commonly identified by clinicians who evaluate and treat swallowing impairment despite a lack of research in this area. The purpose of this study was to understand the current role of swallowing-related fatigue in dysphagia evaluation with respect to (a) clinician practices, (b) perspectives, and (c) desire for resources regarding swallowing-related fatigue. Method A survey was conducted by licensed speech-language pathologists who evaluate and treat adult dysphagia. The survey was distributed via dysphagia-focused groups on Facebook and Special Interest Group 13. Data were analyzed descriptively and by thematic analysis for free-text response questions. Results Out of 426 prospective respondents, 311 completed the survey (response rate = 73.0%). While 86% of respondents agreed that fatigue may be a concern for individuals with swallowing impairment, there was wide variability in how clinicians define and evaluate swallowing-related fatigue, and the majority (62%) define fatigue in two or more ways. Explicit evaluation of fatigue was reportedly conducted by 45% of respondents during the Clinical Swallowing Evaluation, by 38% during videofluoroscopic swallowing study, and by 53% during Flexible Endoscopic Evaluation of Swallowing. The most common methods for identifying fatigue were general declines in performance over the course of the assessment. Respondents reported much more reliance on patient report during Clinical Swallowing Evaluation (41%) compared to videofluoroscopic swallowing study (7%) and fiberoptic endoscopic evaluation of swallowing (5%). Only 7% of respondents reported being aware of any standardized methods for assessing fatigue, while 97% of respondents affirmed interest in incorporating standardized methods for assessing swallow-related fatigue. Conclusions Our results demonstrated wide variability in how currently practicing clinicians define and evaluate swallowing-related fatigue, despite the vast majority considering fatigue to be an important factor in dysphagia evaluation. This study highlights a critical gap in the clinical evaluation of swallowing and requires significant further study to guide clinical practice.

Cardiopulmonary Capacity in Overweight and Obese Children and Adolescents: A Cross-Sectional Study

Background: One of the objective methods of assessing the level of cardiopulmonary capacity in overweight and obese children and adolescents is cardiopulmonary exercise testing (CPET).

Aims: The purpose of present study is an evaluation of aerobic capacity in high body mass index (BMI) children and adolescents by comparing them with a normal weight control group by CPET.

Methods and Procedures: The subjects were recruited from participants of the Program of Treatment for Overweight and Obese Children organized by a local pediatric rehabilitation center in Poland. Based on BMI for age and gender, two validation groups were selected: (1) a group of overweight children (n = 49) and (2) a group of obese children (n = 48). The study included also 53 normal weight participants as a reference group (REF). The study consisted of two parts: anthropometric measurements and CPET. The Godfrey protocol for CPET was applied.

Outcomes and Results: In this study, obese children and adolescents showed similar absolute VO_2peak values in liters per minute (1.64 L/min) compared to overweight children (1.48 L/min), but significantly higher than children with normal body weight (1.39 L/min). The obese children and adolescents presented lower VO_2peak in relation to body weight (25.44 ml/kg/min) compared to their peers with normal body weight (36.5 ml/kg/min), and overweight children (29.18 ml/kg/min).

Conclusion and Implications: The main finding of our study was recognition of significant differences between cardiopulmonary capacity parameters in obese children in comparison not only to normal weight peers, but to overweight, too.

Comparative Trial of the Effects of Left Ventricular and Biventricular Pacing on Indices of Cardiac Function and Clinical Course of Patients With Heart Failure: Rationale and Design of the READAPT Randomized Trial

Nonresponse to cardiac resynchronization therapy (CRT) has been related with right ventricular dysfunction. Ventriculoarterial coupling (VAC) assesses energy efficiency of the failing heart and stroke work maximization for a given contractility, for both systemic and pulmonary circulations. Preferential left ventricular pacing (pLVP) can overcome iatrogenic right ventricular dysfunction by achieving left ventricle resynchronization and by allowing for intrinsic activation of the right side, with ramifications extending beyond cardiac output and atrial fibrillation occurrence. In the present article, we detail the design of a single-center randomized clinical trial to evaluate the effects of a pLVP algorithm. More specifically, following randomization of 220 CRT-eligible patients to standard biventricular pacing and pLVP, their clinical course will be followed for 12 months, through echocardiography to study indices of systolic and diastolic function of ventricles, left and right side VAC to evaluate efficiency, and cardiopulmonary exercise test to objectively document improvements in functional status, as well as a self-reported quality of life questionnaire. Device programming will be based on echocardiography-evaluated maximization of stroke volume and subsequent interventricular and atrioventricular delay adjustments delegated to the device. Findings of this trial may provide evidence for alternative programming of the devices, linking pLVP to improved clinical outcomes.

Diagnosis in children with exercise-induced respiratory symptoms: A multi-center study

OBJECTIVE

Exercise-induced respiratory symptoms (EIS) are common in childhood and reflect different diseases that can be difficult to diagnose. In children referred to respiratory outpatient clinics for EIS, we compared the diagnosis proposed by the primary care physician with the final diagnosis from the outpatient clinic and described diagnostic tests and treatments.

DESIGN

An observational study of respiratory outpatients aged 0-16 years nested in the Swiss Paediatric Airway Cohort (SPAC).

PATIENTS

We included children with EIS as the main reason for referral. Information about diagnostic investigations, final diagnosis, and treatment prescribed came from outpatient records. We included 214 children (mean age 12 years, range 2-17, 54% males) referred for EIS.

RESULTS

The final diagnosis was asthma in 115 (54%), extrathoracic dysfunctional breathing (DB) in 35 (16%), thoracic DB in 22 (10%), asthma plus DB in 23 (11%), insufficient fitness in 10 (5%), chronic cough in 6 (3%), and other diagnoses in 3 (1%). Final diagnosis differed from referral diagnosis in 115 (54%, 95%-CI 46%-60%). Spirometry, body plethysmography, and exhaled nitric oxide were performed in almost all, exercise-challenge tests in a third, and laryngoscopy in none. 91% of the children with a final diagnosis of asthma were prescribed inhaled medication and 50% of children with DB were referred to physiotherapy.

CONCLUSIONS

Diagnosis given at the outpatient clinic often differed from the diagnosis proposed by the referring physician. Diagnostic evaluations, management, and follow-up differed between clinics and diagnostic groups highlighting the need for evidence-based diagnostic guidelines and harmonized procedures for children seen for EIS.

Response of the oxygen uptake efficiency slope to exercise training in patients with chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) patients have poor cardiorespiratory fitness. Although cardiopulmonary exercise testing (CPET) is a universal assessment of cardiorespiratory fitness, values taken at 'peak' effort are strongly influenced by motivation and the choice of test endpoint. The oxygen uptake efficiency slope (OUES) integrates cardiovascular, musculoskeletal, and respiratory function into a single index to provide a more pragmatic and safer alternative to maximal testing. No research has explored whether exercise can improve the OUES in CKD patients.

METHODS

Thirty-two patients with non-dialysis CKD were recruited into a 12-week exercise program consisting of mixed aerobic and resistance training three times a week. CPET was conducted at baseline, and then, following a 6-week control period, at pre- and post-exercise intervention. Direct measurements of oxygen consumption (V̇O2) and ventilatory parameters were collected. The OUES was calculated as the relationship between V̇O2 and the log10 of minute ventilation (V̇E).

RESULTS

No changes were observed in any variable during the control period, although modest increases in V̇O2peak were observed. No meaningful changes were observed as a result of exercise in any cardiorespiratory value obtained. The OUES calculated at 100%, 90%, 75%, and 50% of exercise duration did not change significantly after 12 weeks of exercise training.

CONCLUSION

Our results show that 12 weeks of exercise training had no beneficial effects on the OUES, which supports the modest change observed in V̇O2peak. The lack of change in the OUES and other parameters could indicate a dysfunctional cardiorespiratory response to exercise in patients with CKD, likely mediated by dysfunctional peripheral metabolic mechanisms.

Exercise capacity in children with bronchopulmonary dysplasia at school age

OBJECTIVE

To assess the exercise capacity, exercise habits, and lung function of preterm born children with bronchopulmonary dysplasia (BPD) compared to term born controls at school age.

METHODS

Cardiopulmonary exercise test (CPET) by cycle ergometer and pulmonary function test were performed in children with BPD (n = 42) and compared with a term born control group (n = 42). Daily activity, participation in sports and respiratory symptoms were assessed by questionnaire.

RESULTS

Children with BPD versus controls had significantly lower values for oxygen consumption (V̇O₂ [mL/min] 1442 ± 417 vs. 1766 ± 541), minute ventilation (VE [L/min] 48 ± 14.92 vs. 60 ± 18.33), and workload (W [watt] 96.1 ± 16.7 vs. 110.6 ± 17.2) at peak exercise and a lower anaerobic threshold (VO₂ AT [mL/min] 1183 ± 345 vs. 1382 ± 398). When corrected for weight, only for the workload (2.7 ± 0.5 vs. 3.1 ± 0.5, p = 0.0013) did significant differences persist. The forced expiratory volume in 1 s and forced expiratory flow between 25 and 75% of expired forced vital capacity were significantly reduced in the BPD group (p < 0.0001). Children with BPD have a higher risk of reporting difficulties in physical activity (OR 2.5) and of suffering from wheezing or shortness of breath while exercising (OR 2.5).

CONCLUSION

Compared to term born controls, children with BPD at school age show airflow obstruction, a lower workload in CPET, and more respiratory symptoms related to physical activity. The comparable oxygen consumption based on weight suggests a functionally normal alveolar compartment.

Multidisciplinary lifestyle intervention in children and adolescents - results of the project GRIT (Growth, Resilience, Insights, Thrive) pilot study

BACKGROUND

During childhood and adolescence leading behavioural risk factors for the development of cardiometabolic diseases include poor diet quality and sedentary lifestyle. The aim of this study was to determine the feasibility and effect of a real-world group-based multidisciplinary intervention on cardiorespiratory fitness, diet quality and self-concept in sedentary children and adolescents aged 9 to 15 years.

METHODS

Project GRIT (Growth, Resilience, Insights, Thrive) was a pilot single-arm intervention study. The 12-week intervention involved up to three outdoor High Intensity Interval Training (HIIT) running sessions per week, five healthy eating education or cooking demonstration sessions, and one mindful eating and Emotional Freedom Technique psychology session. Outcome measures at baseline and 12-week follow-up included maximal graded cardiorespiratory testing, the Australian Child and Adolescent Eating Survey, and Piers-Harris 2 children's self-concept scale. Paired samples t-test or Wilcoxon signed-rank test were used to compare baseline and follow-up outcome measures in study completers only.

RESULTS

Of the 38 recruited participants (median age 11.4 years, 53% male), 24 (63%) completed the 12-week intervention. Dropouts had significantly higher diet quality at baseline than completers. Completers attended a median 58 (IQR 55-75) % of the 33 exercise sessions, 60 (IQR 40-95) % of the dietary sessions, and 42% attended the psychology session. No serious adverse events were reported. Absolute VO₂peak at 12 weeks changed by 96.2 ± 239.4 mL/min (p = 0.06). As a percentage contribution to energy intake, participants increased their intake of healthy core foods by 6.0 ± 11.1% (p = 0.02) and reduced median intake of confectionary (- 2.0 [IQR 0.0-3.0] %, p = 0.003) and baked products (- 1.0 [IQR 0.0-5.0] %, p = 0.02). Participants significantly improved self-concept with an increase in average T-Score for the total scale by 2.8 ± 5.3 (p = 0.02) and the 'physical appearance and attributes' domain scale by median 4.0 [IQR 0.5-4.0] (p = 0.02).

CONCLUSIONS

The 12-week group-based multidisciplinary lifestyle intervention for children and adolescents improved diet quality and self-concept in study completers. Future practice and research should focus on providing sustainable multidisciplinary lifestyle interventions for children and adolescents aiming to improve long-term health and wellbeing.

TRIAL REGISTRATION

ANZCTR, ACTRN12618001249246. Registered 24 July 2019 - Retrospectively registered.

Aerobic capacity attainment and reasons for cardiopulmonary exercise test termination in people with cancer: a descriptive, retrospective analysis from a single laboratory

PURPOSE

Aerobic exercise prescriptions in clinical populations commonly involve target intensities based on cardiopulmonary exercise tests (CPET). CPETs are often discontinued prior to a patient achieving true maximum oxygen consumption (VO₂ max) which can adversely affect exercise dose and efficacy monitoring; however, reasons for early discontinuation are poorly reported. Accordingly, we explored the CPET termination reasons in persons with cancer participating in exercise intervention studies.

METHODS

This study comprised of an exploratory, descriptive analysis of retrospective CPET data (VO₂ and anaerobic threshold) and termination reasons in a convenience sample of people with cancer participating in exercise intervention studies in a single laboratory. CPETs were standardized using the modified Bruce treadmill protocol with expired gas collection and analysis using a metabolic cart. VO₂ max was considered "met" when participants demonstrated (a) oxygen consumption plateau or (b) two of the following criteria: rating of perceived exertion ≥ 9/10, respiratory exchange ratio ≥ 1.15, and/or heart rate of 95% of age-predicted maximum. The frequency and distribution of reasons for test termination relative to the number of CPET exposures for the participants were reported.

RESULTS

Forty-four participants engaged in exercise studies between February 2016 and March 2018 provided data for the analysis. Participants completed up to three CPETs during this period (total of 78 CPETs in the current analysis). Eighty-six percent of all CPETs were terminated prior to achieving VO₂ max verification criteria and no tests resulted in an oxygen consumption plateau. For those that did not demonstrate achievement of VO₂ max verification criteria, reasons for discontinuation were distributed as follows: equipment discomfort-49%, volitional peak-36%, and physical discomfort-14.9%. For those who met VO₂ max criteria, volitional peak was the most common reason for test termination (45.5%), followed by physical discomfort (36.4%), and equipment discomfort (18.2%).

CONCLUSIONS

In our sample of cancer survivors, VO₂ max criteria were infrequently met with equipment discomfort being a primary reason for participant-driven test termination. Protocol and equipment considerations are necessary for interpretation and application of CPET findings in clinical practice.

Physiological and Symptomatic Responses to Arm versus Leg Activities in People with Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis

While the mechanisms underlying exercise limitations and symptoms during leg activities have been investigated in detail, knowledge of potential differences between leg and arm activities are not well understood and results from individual studies are contradictory. Thus, the aim of the present study was to synthesize physiological and symptomatic responses during activities involving the arms relative to activities involving the legs in people with Chronic Obstructive Pulmonary Disease (COPD). Any study with a cross-sectional comparison of acute physiological (cardiorespiratory, metabolic) and symptomatic responses to activities performed with the arms versus the legs were included. Studies were sub-grouped based on the type of activity performed (cycle ergometer, resistance exercises, or functional test/activities). Eighteen studies with 423 individuals with COPD were included. Leg cycle ergometer resulted in greater tidal volume (137 mL), minute ventilation (4.8 L/min), and oxygen consumption (164 mL/min) than arm cycle ergometer, while symptomatic responses were similar. Resistance exercises resulted in similar physiological and symptomatic responses irrespective of whether the legs or the arms were involved while studies on functional activities report different results depending on the type and intensity of the activity performed. With the exception of cycle ergometer activities, physiological and symptomatic responses do not seem to depend on whether the arms or the legs are used, but rather seem to be task and intensity dependent. These novel findings suggest, for example, that strategies used to increase exercise tolerance should not be dependent on whether the arms or the legs are used, but rather the intensity of specific activity performed.

Frailty In Patients Undergoing Vascular Surgery: A Narrative Review Of Current Evidence

Frailty is presumably associated with an elevated risk of postoperative mortality and adverse outcome in vascular surgery patients. The aim of our review was to identify possible methods for risk assessment and prehabilitation in order to improve recovery and postoperative outcome. The literature search was performed via PubMed, Embase, OvidSP, and the Cochrane Library. We collected papers published in peer-reviewed journals between 2001 and 2018. The selection criterion was the relationship between vascular surgery, frailty and postoperative outcome or mortality. A total number of 52 publications were included. Frailty increases the risk of non-home discharge independently of presence or absence of postoperative complications and it is related to a higher 30-day mortality and major morbidity. The modified Frailty Index showed significant association with elevated risk for post-interventional stroke, myocardial infarction, prolonged in-hospital stays and higher readmission rates. When adjusted for comorbidity and surgery type, frailty seems to impact medium-term survival (within 2 years). Preoperative physical exercising, avoidance of hypalbuminemia, psychological and cognitive training, maintenance of muscle strength, adequate perioperative nutrition, and management of smoking behaviours are leading to a reduced length of stay and a decreased incidence of readmission rate, thus improving the effectiveness of early rehabilitation. Pre-frailty is a dynamically changing state of the patient, capable of deteriorating or improving over time. With goal-directed preoperative interventions, the decline can be prevented.

Effects of Three Months of Detraining on the Health Profile of Older Women after a Multicomponent Exercise Program

Physical exercise results in very important benefits including preventing disease and promoting the quality of life of older individuals. Common interruptions and training cessation are associated with the loss of total health profile, and specifically cardiorespiratory fitness. Would detraining (DT) promote different effects in the cardiorespiratory and health profiles of trained and sedentary older women? Forty-seven older women were divided into an experimental group (EG) and a control group (CG) (EG: n = 28, 70.3 ± 2.3 years; CG: n = 19, 70.1 ± 5.6 years). Oxygen uptake (VO₂₎ and health profile assessments were conducted after the exercise program and after three months of detraining. The EG followed a nine-month multicomponent exercise program before a three-month detraining period. The CG maintained their normal activities. Repeated measures ANOVA showed significant increases in total heath and VO₂ (p < 0.01) profile over a nine-month exercise period in the EG and no significant increases in the CG. DT led to greater negative effects on total cholesterol (4.35%, p < 0.01), triglycerides (3.89%, p < 0.01), glucose (4.96%, p < 0.01), resting heart rate (5.15%, p < 0.01), systolic blood pressure (4.13%, p < 0.01), diastolic blood pressure (3.38%, p < 0.01), the six-minute walk test (7.57%, p < 0.01), Pulmonary Ventilation (VE) (10.16%, p < 0.01), the Respiratory Exchange Ratio (RER) (9.78, p < 0.05), and VO₂/heart rate (HR) (16.08%, p < 0.01) in the EG. DT may induce greater declines in total health profile and in VO₂, mediated, in part, by the effectiveness of multicomponent training particularly developed for older women.

A Systematic Approach to Interpreting the Cardiopulmonary Exercise Test in Pediatrics

The use of cardiopulmonary exercise testing in pediatrics provides critical insights into potential physiological causes of unexplained exercise-related complaints or symptoms, as well as specific pathophysiological patterns based on physiological responses or abnormalities. Clinical interpretation of the results of a cardiopulmonary exercise test in pediatrics requires specific knowledge with regard to pathophysiological responses and interpretative strategies that can be adapted to address concerns specific to the child's medical condition or disability. In this review, the authors outline the 7-step interpretative approach that they apply in their outpatient clinic for diagnostic, prognostic, and evaluative purposes. This approach allows the pediatric clinician to interpret cardiopulmonary exercise testing results in a systematic order to support their physiological reasoning and clinical decision making.

Association between skeletal muscle mass and cardiorespiratory fitness in community-dwelling elderly men

BACKGROUND

Sarcopenia reduces physical ability and cardiorespiratory fitness (CRF), leading to poor quality of life.

AIM

The aim of this study was to investigate the relationship between skeletal muscle mass and CRF in elderly men.

METHODS

We assessed 102 community-dwelling men over 60 years old. Appendicular skeletal muscle mass (ASM) was determined using bioelectrical impedance analysis, and the skeletal muscle mass index (SMI) was calculated as ASM divided by the square of height. Subjects with an SMI less than 7.0 kg/m² were included in the sarcopenic group, as recommended by the Asian Working Group for Sarcopenia. To investigate CRF parameters, a cardiopulmonary exercise test was performed using the Bruce protocol. CRF parameters were subdivided into aerobic capacity, cardiovascular response, and ventilatory response.

RESULTS

Of the 102 subjects, 15 (14.7%) were included in the sarcopenic group. There were significant correlations between SMI and peak oxygen consumption (VO_2peak) (r = 0.597, p < 0.001), and between SMI and VO_2peak/weight (r = 0.268, p = 0.024). Moreover, there were positive correlations between SMI and first ventilatory threshold (VT1) (r = 0.352, p = 0.008) and between SMI and VT1/weight (r = 0.189, p = 0.039). Additionally, peak oxygen pulse (O₂pulse_peak) was significantly correlated with SMI (r = 0.558, p < 0.001). VO_2peak, VO_2peak/weight and O₂pulse_peak showed significant differences between the sarcopenic and non-sarcopenic groups (p < 0.05, all). In multiple linear regression analyses, the factor related to VO_2peak was SMI (β = 0.473, p < 0.001) and that related to O₂pulse_peak was also SMI (β = 0.442, p < 0.001).

DISCUSSION AND CONCLUSIONS

This study demonstrated that skeletal muscle mass might be closely associated with CRF. Therefore, sarcopenia should be appropriately managed to improve an individual's CRF.

Atrial septal defect and exercise capacity: value of cardio-pulmonary exercise test in assessment and follow-up

Nearly four decades ago, the World Health Organization stated that functional capacity explorations best reflected the impact of a chronic disease on quality of life. Today, cardio-pulmonary exercise test (CPET) is recommended in the follow-up of patients with congenital heart diseases (CHDs). Indeed, the maximum oxygen uptake (VO_2max) and the ventilatory efficiency (VE/VCO₂ slope) correlate with both the prognosis and the quality of life in this population. Atrial septal defects (ASDs) represent the second most frequent CHD and are usually considered as simple CHDs. However, the exercise capacity of ASD patients may be impaired. Therefore, the CPET provides important information in assessment and follow-up of patients with ASDs, for both children and adults. Exercise capacity of patients with unrepaired ASDs depends on the importance of the shunt, the right ventricular (RV) function and volume overload, the level of pulmonary arterial pressure, and the occurrence of arrhythmias. For repaired ASDs, exercise capacity also depends on the delay before closure and the type of procedure (catheter or surgery). In most cases, the exercise capacity is nearly normal and CPET contributes to promote sports participation. In addition, a regular CPET follow-up is necessary to evaluate the occurrence, severity and physiological mechanisms of comorbidities, i.e., heart failure, pulmonary hypertension and arrhythmia. Furthermore, CPET follow-up in patients with ASDs may detect early onset of muscular deconditioning, for which cardiac rehabilitation may be considered.

Acute responses to sprint-interval and continuous exercise in adults with and without exercise-induced bronchoconstriction

The purpose was to compare the airway response to sprint interval exercise (SIE) and continuous exercise (CE) in active adults with exercise-induced bronchoconstriction (EIBC), and to compare ventilatory and oxygen delivery responses between adults with and without EIBC. Adults with EIBC (n = 8, 22.3 ± 3.0 years) and adults without EIBC (n = 8, 22.3 ± 3.0 years) completed a SIE (4 × 30 s sprints separated by 4.5 min of active recovery) and CE (20 min at 65% peak power output) session. Lung function was assessed at baseline, during exercise, and up to 20 min post-exercise. Ventilatory parameters and tissue saturation index (TSI) were recorded continuously throughout the sessions. The decline in forced expiratory volume in 1 s was similar following SIE (-8.6 ± 12.6%) and CE (-9.0 ± 9.3%) in adults with EIBC. There were no significant differences in any of the ventilatory parameters or in TSI during SIE or CE between those with and without EIBC. These findings suggest that SIE and CE affect airway responsiveness to a similar extent. Future research using a lower intensity CE protocol in an inactive sample of adults with EIBC is needed.

Effects of pump speed changes on exercise capacity in patients supported with a left ventricular assist device-an overview

The implantation of left ventricular assist devices (LVAD) has been established as a successful treatment for terminal heart failure (HF) for many years. Patient benefits include significantly improved survival, as well as improved quality of life. However, peak exercise capacity following LVAD implantation remains considerably restricted. This could be due to the predominate use of continuous-flow pumps, which operate at a fixed rotational speed and do not adapt to exercise conditions. Therefore, current research is focused on whether, and to what extent, adaptations in pump speed can influence and improve patient exercise capacity. We performed a systematic PubMed literature search on this topic, and found 11 relevant studies with 161 patients. Exercise time, peak work load, total cardiac output (TCO), peak oxygen consumption (peak VO₂) and, if available, values at the anaerobic threshold (AT) were all taken into consideration. Possible complications were documented. This paper aims to compare the results from these studies in order to discuss the effects of pump speed adaptations on exercise capacity.

The physiologic impact of pectus excavatum repair

The adverse physiologic effects of pectus excavatum and subsequent resolution following correction have been a subject of controversy. There are numerous accounts of patients reporting subjective improvement in exercise tolerance after surgery, but studies showing clear and consistent objective data to corroborate this phenomenon physiologically have been elusive. This is partially due to a lack of consistent study methodologies but even more so due to a mere paucity of data. As experts in the repair of pectus excavatum, it is not uncommon for pediatric surgeons to operate on adult patients. For this reason, this review evaluates the contemporary literature to provide an understanding of the physiologic impact of repairing pectus excavatum on pediatric and adult patients separately.

Spontaneous Coronary Artery Dissection: Current State of the Science: A Scientific Statement From the American Heart Association

Spontaneous coronary artery dissection (SCAD) has emerged as an important cause of acute coronary syndrome, myocardial infarction, and sudden death, particularly among young women and individuals with few conventional atherosclerotic risk factors. Patient-initiated research has spurred increased awareness of SCAD, and improved diagnostic capabilities and findings from large case series have led to changes in approaches to initial and long-term management and increasing evidence that SCAD not only is more common than previously believed but also must be evaluated and treated differently from atherosclerotic myocardial infarction. High rates of recurrent SCAD; its association with female sex, pregnancy, and physical and emotional stress triggers; and concurrent systemic arteriopathies, particularly fibromuscular dysplasia, highlight the differences in clinical characteristics of SCAD compared with atherosclerotic disease. Recent insights into the causes of, clinical course of, treatment options for, outcomes of, and associated conditions of SCAD and the many persistent knowledge gaps are presented.

Cardiorespiratory and muscle oxygenation responses to low-load/high-repetition resistance exercises in COPD and healthy controls

Single-limb exercises have been used as a strategy to improve aerobic exercise tolerance in patients with chronic obstructive pulmonary disease (COPD) by alleviating the cardiopulmonary demand. We asked whether this strategy would also apply to cardiorespiratory demand and amount of work performed during single-limb and two-limb low-load/high-repetition resistance exercises in 20 patients with COPD [forced expiratory volume in 1 s (FEV1) = 1.0 liters, 38% of predicted] and 15 age-, sex-, and activity-matched healthy controls. Peak ventilation, peak oxygen consumption (V̇o2), and peak heart rate (HR) were assessed to document cardiorespiratory demand during shoulder flexion and knee extension exercises while exercise tolerance was assessed by the total amount of work achieved. In addition, changes in myoglobin-deoxyhemoglobin level (Δdeoxy-[Hb/Mb]) were measured during single-limb knee extension. In COPD, single-limb shoulder flexion and knee extension elicited higher localized workloads than two-limb exercises (21 and 24% higher workloads for the former exercise) while cardiopulmonary demand was 8–16% higher during two-limb exercises. When expressed as a percentage of peak values achieved during incremental cycle ergometry, peak V̇O2 and HR were similarly high during single-limb shoulder flexion and knee extension exercises, representing 90% of peak HR and 60% of peak V̇O2. Apart from single-limb knee extension, cardiorespiratory demand per kilogram work during low-load/high-repetition knee extension and shoulder flexion exercises was higher in patients with COPD than in healthy controls (range 27–122%, P < 0.0125). Δdeoxy-[Hb/Mb] of the quadriceps during knee extension was similar between the two groups, while Δdeoxy-[Hb/Mb] per kilogram work was higher in patients with COPD. We conclude that 1) in patients with COPD, single-limb exercises resulted in lower peak cardiorespiratory demand as well as higher localized workloads compared with two-limb exercises; 2) compared with healthy controls, the cardiorespiratory demand, either expressed per unit of work or relative to peak capacity, was higher in patients with COPD than in controls during low-load/high-repetition resistance exercises, irrespective of the involvement of one or two limbs or of the upper or lower extremity; 3) quadriceps muscle deoxygenation per unit of work during low-load/high-repetition knee extension was increased in COPD compared with controls; and 4) single- and two-limb low-load/high-repetition knee extension and shoulder flexion resistance exercises imposed a similar burden on the cardiorespiratory system, resulting in a higher cardiorespiratory demand per kilogram work performed during shoulder flexion compared with knee extension, in both COPD and healthy controls.

NEW & NOTEWORTHY In chronic obstructive pulmonary disease (COPD), single-limb knee extension and shoulder flexion resulted in a lower peak cardiorespiratory response as well as larger localized exercise workloads compared with two-limb exercises. Cardiorespiratory and quadriceps deoxygenation cost per kilogram work was greater in COPD compared with healthy controls, despite similar acute responses. Compared with knee extension, shoulder flexion imposed a similar burden on the cardiorespiratory system in patients with COPD and healthy controls.

Streamlining cardiopulmonary exercise testing for use as a screening and tracking tool in primary care

Cardiopulmonary exercise testing (CPET) using a spectrum of different approaches demonstrates usefulness for objectively assessing patient disease severity in clinical and research settings. Still, an absence of trained specialists and/or improper data interpretation techniques can pose major limitations to the effective use of CPET for the clinical classification of patients. This study aimed to test an automated disease likelihood scoring algorithm system based on cardiopulmonary responses during a simplified step-test protocol. For patients with heart failure (HF), pulmonary hypertension (PAH), obstructive lung disease (OLD), or restrictive lung disease (RLD), we compared patient scores stratified into one of four "silos" generated from our novel algorithm system against patient evaluations provided by expert clinicians. Patients with HF (n = 12), PAH (n = 9), OLD (n = 16), or RLD (n = 10) performed baseline pulmonary function testing followed by submaximal step-testing. Breath-by-breath measures of ventilation and gas exchange, in addition to oxygen saturation and heart rate were collected continuously throughout testing. The algorithm demonstrated close alignment with patient assessments provided by clinical specialists: HF (r = 0.89, P < 0.01); PAH (r = 0.88, P < 0.01); OLD (r = 0.70, P < 0.01); and RLD (r = 0.88, P < 0.01). Furthermore, the algorithm was capable of differentiating major disease from other disease pathologies. Thus, in a clinically relevant manner, these data suggest this simplified automated disease algorithm scoring system used during step-testing to identify the likelihood that patients have HF, PAH, OLD, or RLD closely correlates with patient assessments conducted by trained clinicians.

Cardiopulmonary Exercise Test Methodology for Assessing Exertion Intolerance in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Background: Concise methodological directions for administration of serial cardiopulmonary exercise testing (CPET) are needed for testing of patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). Maximal CPET is used to evaluate the coordinated metabolic, muscular, respiratory and cardiac contributions to energy production in patients with ME/CFS. In this patient population, CPET also elicits a robust post-exertional symptom flare (termed, post-exertional malaise); a cardinal symptom of the disease. CPET measures are highly reliable and reproducible in both healthy and diseased populations. However, evidence to date indicates that ME/CFS patients are uniquely unable to reproduce CPET measures during a second test, despite giving maximal effort during both tests, due to the effects of PEM on energy production. Methodology: To document and assess functional impairment due to the effects of post-exertional malaise in ME/CFS, a 2-day CPET procedure (2-day CPET) has been used to first measure baseline functional capacity (CPET1) and provoke post-exertional malaise, then assess changes in CPET variables 24 h later with a second CPET to assess the effects of post-exertional malaise on functional capacity. The second CPET measures changes in energy production and physiological function, objectively documenting the effects of post-exertional malaise. Use of CPET as a standardized stressor to induce post-exertional malaise and quantify impairment associated with post-exertional malaise has been employed to examine ME/CFS pathology in several studies. This article discusses the results of those studies, as well as the standardized techniques and procedures for use of the 2-day CPET in ME/CFS patients, and potentially other fatiguing illnesses. Conclusions: Basic concepts of CPET are summarized, and special considerations for performing CPET on ME/CFS patients are detailed to ensure a valid outcome. The 2-day CPET methodology is outlined, and the utility of the procedure is discussed for assessment of functional capacity and exertion intolerance in ME/CFS.

Subjective responses to sprint interval exercise in adults with and without Exercise-induced bronchoconstriction

OBJECTIVE

Little is known of the subjective response to exercise that involves short "all out" bursts of effort, separated by recovery periods (sprint interval exercise (SPRINT)) among adults with exercise-induced bronchoconstriction (EIBC). The purpose of this study was to compare subjective responses to SPRINT and moderate intensity continuous exercise (MOD) among adults with EIBC, and to compare these responses between adults with EIBC and those without EIBC.

METHODS

Eight adults (22.3 ± 3.0 years) with EIBC, and eight adults (22.3 ± 3.0 years) without EIBC completed a SPRINT (4 × 30 second sprints separated by 4.5 minutes of active recovery) and MOD (20 minutes at 65% peak power output) session in random order. Self-reported affect, perceived breathlessness, and perceived exertion were recorded throughout exercise using validated scales. Enjoyment was assessed following exercise.

RESULTS

Differences between SPRINT and MOD were observed such that affect and perceived breathlessness were worse during the initial stages of SPRINT than MOD; however, differences disappeared by the end of exercise. Enjoyment was similar for SPRINT and MOD in the EIBC group (SPRINT: 72.9 ± 20.0 vs. MOD: 79.5 ± 20.5, p = 0.25), and between groups for SPRINT and MOD.

CONCLUSIONS

Perceived breathlessness may impact affect during the early stages of exercise among those with EIBC. Post-exercise enjoyment appears to be similar between SPRINT and MOD. Future research is needed to better understand the relationship between ventilation patterns, exercise intensity, and enjoyment of exercise among those with EIBC.

Algorithm for Predicting Disease Likelihood From a Submaximal Exercise Test

We developed a simplified automated algorithm to interpret noninvasive gas exchange in healthy subjects and patients with heart failure (HF, n = 12), pulmonary arterial hypertension (PAH, n = 11), chronic obstructive lung disease (OLD, n = 16), and restrictive lung disease (RLD, n = 12). They underwent spirometry and thereafter an incremental 3-minute step test where heart rate and SpO2 respiratory gas exchange were obtained. A custom-developed algorithm for each disease pathology was used to interpret outcomes. Each algorithm for HF, PAH, OLD, and RLD was capable of differentiating disease groups (P < .05) as well as healthy cohorts (n = 19, P < .05). In addition, this algorithm identified referral pathology and coexisting disease. Our primary finding was that the ranking algorithm worked well to identify the primary referral pathology; however, coexisting disease in many of these pathologies in some cases equally contributed to the cardiorespiratory abnormalities. Automated algorithms will help guide decision making and simplify a traditionally complex and often time-consuming process.

Exercise Testing: Who, When, and Why?

There are different modalities of exercise testing that can provide valuable information to physicians about patient and athlete fitness and cardiopulmonary status. Cardiopulmonary exercise testing (CPX) is a form of exercise testing that measures ventilatory and gas exchange, heart rate, electrocardiogram, and blood pressures to provide detailed information on the cardiovascular, pulmonary, and muscular systems. This testing allows an accurate quantification of functional capacity/measure of exercise tolerance, diagnosis of cardiopulmonary disease, disease-progression monitoring or response to intervention, and the prescription of exercise and training. CPX directly measures inhaled and exhaled ventilator gases to determine the maximal oxygen uptake, which reflects the body's maximal use of oxygen and defines the limits of the cardiopulmonary system. CPX is the ideal modality to evaluate causes of exertional fatigue and dyspnea, especially in complex cases in which the etiology could be cardiac, pulmonary, or deconditioning. Exercise tolerance has become an important outcome measure in patients with chronic obstructive pulmonary disease and congestive heart failure, as well as other chronic diseases, and is a well-recognized predictor of mortality. Older athletes or those with underlying medical conditions could benefit from exercise testing for risk stratification and clearance to participate, as well as to help set their training zones and determine their functional limitations.