Aerobic fitness is associated with lower risk of hospitalization in children with cystic fibrosis

Comparison of the modified shuttle walk test in children with cystic fibrosis and healthy controls

OBJECTIVE

To evaluate and compare performance in the modified shuttle walk test (MSWT) with cardiorespiratory parameters and respiratory muscle strength in children with cystic fibrosis (CF) and healthy controls.

METHODS

A cross-sectional study with children divided into the CF group (CFG) and healthy control group (HCG). Two MSWTs were performed and the data from the test with the longest distance walked and its cardiorespiratory parameters (blood pressure, respiratory rate, heart rate (HR), oxygen saturation, and dyspnea sensation) were considered, the last three every 4 levels. Respiratory muscle strength was evaluated using a manometer. The Wilcoxon test was used to compare the parameters before and after the MSWT, and the Mann-Whitney and independent t-tests were applied to compare the data between the groups. The distance walked and its association with the variation in cardiorespiratory parameters and respiratory muscle strength were analyzed by Spearman's correlation.

RESULTS

Sixty-two children (31 in each group) participated, with an average age of 10.2 (2.1) years. Children with CF had poorer performance in the average distance walked (CFG 716.7 (274.3)) when compared to the HCG (948.0 (202.8)). Both groups exhibited an increase in all the cardiorespiratory parameters at the end of the test, but the CFG displayed less variation in some parameters. Children with CF presented a positive correlation between distance walked and respiratory muscle strength, HR variation, and systolic blood pressure.

CONCLUSIONS

There was no difference in respiratory muscle strength between the groups. In the CFG, the greater the respiratory muscle strength, the better the performance in the MSWT. The CFG exhibited less variation in cardiorespiratory parameters than the HCG.

Mechanisms of ventilatory limitation to maximum exercise in children and adolescents with chronic airway diseases

INTRODUCTION

Exercise intolerance is common in chronic airway diseases (CAD), but its mechanisms are still poorly understood. The aim of this study was to evaluate exercise capacity and its association with lung function, ventilatory limitation, and ventilatory efficiency in children and adolescents with cystic fibrosis (CF) and asthma when compared to healthy controls.

METHODS

Cross-sectional study including patients with mild-to-moderate asthma, CF and healthy children and adolescents. Anthropometric data, lung function (spirometry) and exercise capacity (cardiopulmonary exercise testing) were evaluated. Primary outcomes were peak oxygen consumption (VO2 peak), forced expiratory volume in 1 s (FEV1 ), breathing reserve (BR), ventilatory equivalent for oxygen consumption (VE /VO2 ) and for carbon dioxide production (VE /VCO2 ), both at the ventilatory threshold (VT1 ) and peak exercise.

RESULTS

Mean age of 147 patients included was 11.8 ± 3.0 years. There were differences between asthmatics and CF children when compared to their healthy peers for anthropometric and lung function measurements. Asthmatics showed lower VO2 peak when compared to both healthy and CF subjects, although no differences were found between healthy and CF patients. A lower BR was found when CF patients were compared to both healthy and asthmatic. Both CF and asthmatic patients presented higher values for VE /VO2 and VE /VCO2 at VT1 when compared to healthy individuals. For both VE /VO2 and VE /VCO2 at peak exercise CF patients presented higher values when compared to their healthy peers.

CONCLUSION

Patients with CF achieved good exercise capacity despite low ventilatory efficiency, low BR, and reduced lung function. However, asthmatics reported reduced cardiorespiratory capacity and normal ventilatory efficiency at peak exercise. These results demonstrate differences in the mechanisms of ventilatory limitation to maximum exercise testing in children and adolescents with CAD.

Validation of the 25 level modified shuttle test in children with cystic fibrosis

OBJECTIVE

To evaluate the validity and reliability of the modified shuttle 25-level test (MST-25) in children with cystic fibrosis (CF).

METHODS

A prospective single center study in clinically stable children with CF. Participants undertook two testing conditions on different days: (1) 2xMST-25 tests; (2) cardiopulmonary exercise test (CPET). Test order was randomized. Nadir oxygen saturation (SpO₂ ), peak heart rate (HR), breathlessness (modified Borg), rate of perceived exertion (RPE), energy expenditure (EE) and metabolic equivalents (MET) from the MST-25 and CPET were compared to assess validity, while outcomes from 2xMST-25 tests were compared for reliability. CPET was performed using breath-by-breath analysis and EE from the MST-25 obtained using the SenseWear Armband.

RESULTS

Strong correlations were found between MST-25 distance and peak oxygen uptake, peak work and minute ventilation on CPET (all r > 0.7, p < 0.01). Moderate correlations were found between MST-25 distance and CPET for METs (r = 0.5) and HR (r = 0.6). Weak associations between tests were evident for nadir SpO₂ (r = 0.1), modified Borg (r_s  = 0.2) and RPE (r_s  = 0.2). Test-retest reliability was excellent for MST-25 distance (ICC 0.91), peak EE (ICC 0.99) and peak METs (ICC 0.90). Good reliability was achieved for HR (ICC 0.84) and modified Borg score (ICC 0.77), while moderate reliability for nadir SpO₂ (ICC 0.64) and RPE (ICC 0.68) was observed.

CONCLUSION

The MST-25 is a valid and reliable field test for the assessment of exercise capacity in children with CF. The MST-25 can be used to accurately monitor exercise capacity and prescribe exercise training, particularly when CPET is not available.

Survey of exercise testing and training in cystic fibrosis clinics in the UK: a decade of progress

OBJECTIVES

Regular exercise testing is recommended for people with cystic fibrosis (pwCF), as is the provision and regular review of exercise training programmes. A previous survey on exercise testing and training for pwCF in the UK was conducted over a decade ago. With the landscape of CF changing considerably during this time, this survey aimed to evaluate UK-based exercise testing and training practices for pwCF a decade on.

DESIGN

Cross-sectional, online survey.

PARTICIPANTS

A survey was distributed electronically to UK CF clinics and completed by the individual primarily responsible for exercise services. Descriptive statistics and qualitative analyses were undertaken.

RESULTS

In total, 31 CF centres participated, representing ~50% of UK specialist clinics. Of these, 94% reported using exercise testing, 48% of which primarily use cardiopulmonary exercise testing. Exercise testing mostly occurs at annual review (93%) and is most often conducted by physiotherapists (62%). A wide variation in protocols, exercise modalities, normative reference values and cut-offs for exercise-induced desaturation are currently used. All centres reportedly discuss exercise training with pwCF; 94% at every clinic appointment. However, only 52% of centres reportedly use exercise testing to inform individualised exercise training. Physiotherapists typically lead discussions around exercise training (74%).

CONCLUSIONS

These data demonstrate that the majority of respondent centres in the UK now offer some exercise testing and training advice for pwCF, representing a marked improvement over the past decade. However, continued efforts are now needed to standardise exercise practices, particularly regarding field testing practices and the translation of test results into personalised training programmes for pwCF.

Current Practice, Barriers to, and Facilitators of Exercise Testing and Training by Physiotherapists in Cystic Fibrosis Specialized Centres in Canada

Purpose: This study surveyed physiotherapists working at Canadian cystic fibrosis (CF) specialized centres to investigate the current practice, barriers to, and facilitators of exercise testing and training. Method: Physiotherapists were recruited from 42 Canadian CF centres. They responded to an e-questionnaire regarding their practice. The data were analyzed using descriptive statistics. Results: Eighteen physiotherapists responded (estimated response rate of 23%); median years of clinical experience was 15 (range, min-max, 3-30) years. Aerobic testing was administered by 44% of respondents, strength testing by 39%, aerobic training by 78%, and strength training by 67%. The most frequently reported barriers across all four types of exercise testing and training were insufficient funding (reported by 56%-67% of respondents), time (50%-61%) and staff availability (56%). More late career than early career physiotherapists reported utilizing aerobic testing (50% vs. 33% of respondents), strength testing (75% vs. 33%), aerobic training (100% vs. 67%), and strength training (100% vs. 33%). Conclusions: Exercise testing and training is underutilized in Canadian CF centres. Experienced physiotherapists reported utilizing exercise testing and training more than less-experienced physiotherapists. Post-graduate education and mentorship, especially for less-experienced clinicians, are recommended to emphasize the importance of exercise testing and training. Barriers of funding, time, and staff availability should be addressed to further improve quality of care.

Normal reference values for aerobic fitness in cystic fibrosis: a scoping review

Objective

The importance of aerobic fitness (VO2peak) in cystic fibrosis (CF) is well established, and regular exercise testing is recommended. To standardise VO2peak, a ‘percentage of predicted’ (%pred) derived from normative reference values (NRV), as promoted by the 2015 European Cystic Fibrosis Society Exercise Working Group (ECFS EWG), can be reported. However, the NRVs used in CF and their relative frequency is unknown.

Method

A scoping review was performed via systematic database searches (PubMed, Embase, Web of Science, SciELO, EBSCO) and forward citation searches for studies that include people with CF and report VO2peakas %pred. Studies were screened using Covidence, and data related to patient demographics, testing modality and reference equations were extracted. Additional analyses were performed on studies published in 2016–2021, following the ECFS EWG statement in 2015.

Results

A total of 170 studies were identified, dating from 1984 to 2022, representing 6831 patients with CF, citing 34 NRV. Most studies (154/170) used cycle ergometry, 15/170 used treadmills, and the remainder used alternative, combination or undeclared modalities. In total, 61/170 failed to declare the NRV used. There were 61 studies published since the ECFS EWG statement, whereby 18/61 used the suggested NRV.

Conclusion

There is a wide discrepancy in NRV used in the CF literature base to describe VO2peakas %pred, with few studies using NRV from the ECFS EWG statement. This high variance compromises the interpretation and comparison of studies while leaving them susceptible to misinterpretation and limiting replication. Standardisation and alignment of reporting of VO2peakvalues are urgently needed.

Effectiveness of Physical Exercise Interventions on Pulmonary Function and Physical Fitness in Children and Adults with Cystic Fibrosis: A Systematic Review with Meta-Analysis

Objective: Physical exercise is associated with several benefits in the treatment of cystic fibrosis (CF), associated with a reduction in patient mortality. The aim of this systematic review was to determine the effectiveness of exercise interventions on physical condition and lung function in children and adults with CF to establish the most appropriate type and dose of physical exercise used so far. Methods: The studies included were randomized controlled trials with physical exercise interventions performed with children or adults with CF, analyzing the effects on pulmonary function, cardiorespiratory capacity, and muscle strength. The variables analyzed in at least four studies in the same population (children or adults) with the same measuring test were included in the meta-analysis. Results:Pulmonary function: There were no changes in the forced expiratory volume 1 s, but mouth expiratory/inspiratory pressures were improved in some studies. Physical fitness: In children, the interventions did not manage to improve the VO2peak (SMD = 0.22; 95%CI: -0.25 to 0.68; p = 0.73) but improved muscle strength. In adults, physical exercise interventions based on high-intensity aerobic training showed positive results in the VO2peak, and in some muscle strength outcomes. Conclusions: Exercise interventions in children and adults with CF are effective in improving muscle strength, cardiovascular capacity, and respiratory muscle function. However, they do not achieve improvements in lung function. The most effective programs are those using strength training or cardiovascular high-intensity interval training, although to date there have been few such interventions.

Elexacaftor-Tezacaftor-Ivacaftor improves exercise capacity in adolescents with cystic fibrosis

OBJECTIVE

Elexacaftor/Tezacaftor/Ivacaftor is a cystic fibrosis transmembrane conductance regulator (CFTR) modulator with the potential to improve exercise capacity. This case series of three adolescents with CF aimed to investigate whether 6 weeks treatment with Elexacaftor/Tezacaftor/Ivacaftor could improve exercise capacity in CFTR modulator naive adolescents with CF.

METHODS

Three adolescents (14.0 ± 1.4 years) with CF (FEV₁ % predicted: 62.5 ± 17.1; F508del/F508del genotype) completed an exhaustive maximal cardiopulmonary exercise test on a cycle ergometer to determine peak oxygen uptake ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:mrow><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> </mml:mrow> <mml:annotation>$\dot{{\rm{V}}}$</mml:annotation></mml:semantics> </mml:math> O_2peak ) and measure changes in gas exchange and ventilation during exercise at 6 weeks. We also analyzed wrist-worn device-based physical activity (PA) data in two of the three cases. Validated acceleration thresholds were used to quantify time spent in each PA intensity category.

RESULTS

Clinically meaningful improvements in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:mrow><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> </mml:mrow> <mml:annotation>$\dot{{\rm{V}}}$</mml:annotation></mml:semantics> </mml:math> O_2peak were observed in all three cases (+17.6%, +52.4%, and +32.9%, respectively), with improvements greatest in those with more severe lung disease and lower fitness at baseline. Although lung function increased in all cases, inconsistent changes in markers of ventilatory and peripheral muscle efficiency likely suggest different mechanisms of improvement in this case group of adolescents with CF. Device-based analysis of PA was variable, with one case increasing and one case decreasing.

CONCLUSION

In this case series, we have observed, for the first time, improvements in exercise capacity following 6 weeks of treatment with Elexacaftor/Tezacaftor/Ivacaftor. Improvements were greatest in the presence of more severe CF lung disease and lower aerobic fitness at baseline. The mechanism(s) responsible for these changes warrant further investigation in larger trials.

One-minute sit-to-stand test is practical to assess and follow the muscle weakness in cystic fibrosis

BACKGROUND

Quadriceps muscle weakness and reduced exercise tolerance are prevalent and associated with a worse prognosis in patients with cystic fibrosis (CF). The one-minute sit-to-stand test (1STST) has been proposed to evaluate functional exercise capacity and quadriceps strength.

RESEARCH QUESTION

The aim of the study was to verify the relationship between the 1STST and the maximal isometric voluntary contraction of the quadriceps (MVCQ) evaluated by the dynamometer in stable patients with CF and to evaluate the impact of intravenous (IV) antibiotherapy.

METHODS

Dynamometer and 1STST were performed in stable patients with CF at a routine visit, the admission and the discharge of an IV antibiotherapy. Patients wore an activity monitor during 72 h during IV treatment.

RESULTS AND SIGNIFICANCE

51 stable patients with CF at a routine visit and 30 treated with IV antibiotherapy were recruited. In stable patients, the 1STST was reduced to a mean of 2101 nxkg (657-SD), representing a median of 79% (7; 142-min; max)) of the predicted values (%PV) as well as the MVCQ to 78.64 N-m (23.21; 170.34), representing 57%PV (26). The 1STST was correlated to MVCQ (r = 0.536; p < 0.0001) and lung function (r = 0.508; p = 0.0001). Over the IV antibiotherapy course, the 1STST improves significantly like lung function and body mass index while a positive trend for MVCQ was observed. The gain of 1STST was correlated to the change in MVCQ (r = 0.441; p = 0.02) and was significantly higher in hospitalized patients versus home therapy. The 1STST is a good alternative to the dynamometer to evaluate and assess muscular weakness for the routine visit and IV antibiotherapy.

The Effect of Dysglycaemia on Changes in Pulmonary and Aerobic Function in Cystic Fibrosis

Cross-sectional studies have reported lower pulmonary and aerobic function during exercise in people with cystic fibrosis-related diabetes (CFRD) compared to non-CFRD counterparts. However, this association has yet to be longitudinally investigated. Therefore, this study examines these differences over time between people with cystic fibrosis (CF) of differing glycaemic status. Annual review data, including cardiopulmonary exercise tests and pulmonary function tests, were retrospectively analysed at baseline (T0, n = 82) and at a one-year follow-up (T1, n = 54). Data was analysed in three groups: normal glucose tolerance (NGT), impaired glucose tolerance (IGT), and CFRD. Further analyses were undertaken, with a dichotomous split of NGT and a combined IGT/CFRD group. At baseline, a significant reduction in the majority of variables, including forced expiratory volume in one second (FEV₁) and maximal oxygen uptake (VO_2max), was observed in the CFRD (n = 19) group compared to NGT (n = 58). At follow-up, no significant differences were observed, and no interaction effect between CFRD status and time was identified. FEV₁ and VO_2max presented with varying directions and magnitudes of change within patients. In summary, patients with CFRD have a reduced aerobic and pulmonary function compared to non-CFRD counterparts, although such changes disappeared at follow up. Varying responses for FEV₁ and VO_2max highlight the need to consider both variables as independent markers of function in CF.

Exercise intolerance in cystic fibrosis-the role of CFTR modulator therapies

Exercise intolerance is common in people with CF (pwCF), but not universal among all individuals. While associated with disease prognosis, exercise intolerance is not simply a reflection of the degree of lung disease. In people with severe CF, respiratory limitations may contribute more significantly to impaired exercise capacity than in those with mild-moderate CF. At all levels of disease severity, there are peripheral factors e.g., abnormal macro- and micro-vascular function that impair blood flow and reduce oxygen extraction, and mitochondrial defects that diminish metabolic efficiency. We discuss advances in understanding the central and peripheral mechanisms underlying exercise intolerance in pwCF. Exploring both the central and peripheral factors that contribute to exercise intolerance in CF can help inform the development of new therapeutic targets, as well as help define prognostic criteria.

Aerobic fitness is associated with extracellular DNA levels in the sputum of patients with cystic fibrosis

AIMS

Patients with cystic fibrosis (CF) develop with progressive loss of lung function and aerobic fitness. However, the precise mechanisms of exercise intolerance are still controversial and appear to be influenced by several factors. This study aimed to evaluate the association of aerobic fitness with free DNA levels in the sputum of patients with CF.

METHODS

This cross-sectional study included patients with CF older than 6 years, free from active exacerbations, but who were able to produce spontaneously expectorated sputum. Extracellular DNA in the sputum was quantified. Lung function (spirometry) and aerobic fitness (cardiopulmonary exercise testing [CPET]) were performed. In addition, demographic, anthropometric and clinical data were collected.

RESULTS

Sixteen patients with a mean age of 19.4 ± 6.9 years and mean forced expiratory volume in the first second (FEV₁ ) of 51.8 ± 28.1 (% of predicted) were included. Mean peak oxygen consumption (VO₂ peak) was 32.8 ± 5.2 mL• kg^-1 • min^-1 , oxygen saturation at the end of the test was 90.6% ± 6.3% and mean extracellular DNA levels was 305.3 ± 153.6 μg/mL. Individuals with a VO₂ peak ≤ 30 mL• kg^-1 • min^-1 (P = .03) and a SpO₂ ≤ 90% at the end of the test (P = .03) had a greater amount of extracellular DNA in the sputum. The proportion of patients with reduced VO₂ peak in the group of patients with the lowest concentration of DNA in the sputum (<243 μg/mL) was significantly lower (0% vs 100%; P = .04).

CONCLUSION

There is an association between the presence of free DNA in sputum and aerobic fitness in patients with CF.

Endurance cycle ergometry tests performed at a sub-maximal work rate elicit peak physiological and symptom responses in adults with cystic fibrosis

Time to symptom limitation (T_lim ) achieved during constant work rate tests is considerably more responsive to change than measures commonly recorded during ramp-based tests, such as peak rate of oxygen uptake and maximal work rate (W_max ). There is limited literature on the use of, and physiological and symptom responses to, constant work rate cycle ergometry tests in people with cystic fibrosis (CF). The results of this study provide evidence that the constant work rate cycle ergometry test, when conducted at 80% of the W_max , elicits peak physiological and symptom responses and appears to be safe in adults with CF. For clinicians prescribing exercise at an intensity approaching or equivalent to 80% of the W_max in a non-laboratory-based setting, consideration needs to be given to the level of supervision and patient monitoring required.

Associations between peak oxygen uptake, lung function, and bronchiectasis in children with cystic fibrosis in the era of CFTR modulators

BACKGROUND

With the emergence of cystic fibrosis transmembrane conductance regulator (CFTR) modulators, forced expiratory volume in 1 s (FEV₁ ) may become a less sensitive measure of pulmonary disease progression in children with cystic fibrosis (CF). Increasing evidence shows that peak oxygen uptake (VO_2peak ) is a strong predictor of prognosis in CF. The primary aim of this study was to describe the associations between peak oxygen uptake, lung function, and bronchiectasis in children with CF in the era of CFTR modulators.

METHODS

Spirometry and a maximal cardiopulmonary exercise test (CPET) were performed on the same day and compared to markers of disease severity. Markers of disease severity included a number of pulmonary exacerbations resulting in hospital admission within the preceding 12 months, body mass index, Pseudomonas aeruginosa (PsA) infection, and bronchiectasis.

RESULTS

Fifty-two subjects (24 female) with CF participated in the study with a mean (SD) age of 13.8 (2.4) years, range 8-18 years. Forty-nine participants met satisfactory criteria for a maximal CPET. A significant correlation was found between relative VO_2peak %predicted and FEV₁ %predicted (r = .546, p < .001). A total of 4/49 children demonstrated an impaired aerobic capacity despite normal spirometry. Participants who had experienced one or more pulmonary exacerbations in the previous 12 months had a significantly lower relative VO_2peak %predicted (p = .02).

CONCLUSIONS

In children with CF who have mild pulmonary disease, there is significant correlation between FEV₁ and VO_2peak . In all, 8.2% of participants had an abnormal CPET result despite normal spirometry, and preceding pulmonary exacerbations were associated with poorer CPET outcomes. CPET may offer important prognostic information for clinical decision making in this new era of CFTR modulators.

Pulmonary rehabilitation for cystic fibrosis: A narrative review of current literature

Pulmonary rehabilitation is a key component in cystic fibrosis care.  This review summarizes the recent evidence in the area of pulmonary rehabilitation for cystic fibrosis in the form of questions and answers regarding interventions, indications, benefits and risks of pulmonary rehabilitation. Pulmonary rehabilitation includes airway clearance techniques, exercise training, education and behaviour change and can improve patients' exercise capacity, muscle strength, quality of life and nutritional status. Airway clearance techniques have beneficial effects for clearing mucous. Over the past years, evidence for the beneficial effects of exercise training on exercise capacity and overall lung health is growing. In cystic fibrosis, multiple factors result in reduced exercise capacity. All modalities of pulmonary rehabilitation should be offered to patients with cystic fibrosis, as the benefits in most cases outweigh the risks, though the optimal regimens need to be yet defined.

Interval versus constant-load exercise training in adults with Cystic Fibrosis

BACKGROUND

The efficacy of interval exercise (IE) compared to constant-load exercise (CLE) training remains unsettled in adults with Cystic Fibrosis (CF).

METHODS

Twenty-four adults with CF were randomised to 30-min IE (100 % peak work capacity (WRpeak) for 30-s alternated with 40 % WRpeak for 30-s; n = 12) or 30-min CLE (70 % WRpeak; n = 12) training, 3 times weekly, for 12 weeks. Isometric quadriceps muscle strength was assessed using a strain gauge Myometer.

RESULTS

The magnitude of improvement in quadriceps muscle strength was greater (p = 0.037) in the IE (by 32 ± 13 Nm) compared to the CLE (by 23 ± 12 Nm) groups. Maximum inspiratory and expiratory mouth pressures were significantly improved only in the IE group (by 30 ± 10 cmH₂O; p = 0.009 and 13 ± 4 cmH₂O; p = 0.007, respectively). Arterial oxygen saturation during training was higher (p = 0.002) for IE (94 ± 1%) compared to CLE (91 ± 1%), whereas dyspnoea scores were lower (p = 0.001) for IE (3.8 ± 0.7) compared to CLE (5.9 ± 0.8) CONCLUSIONS: IE is superior to CLE in improving peripheral and respiratory muscle strength and preferable to CLE because it is associated with lower exercise-induced arterial oxygen desaturation and breathlessness.

"Test-retest reliability and minimal detectable change in TGlittre-P test in children and adolescents with cystic fibrosis"

OBJECTIVE

to provide test-retest reliability for the TGlittre-P in children and adolescents with cystic fibrosis (CFG) and healthy controls (HCG), to establish the minimal detectable change for time in TGlittre-P and comparing the performance in the TGlittre-P test between these populations.

METHOD

A cross-sectional study evaluated 36 children and adolescents aged 6 to 13. Anthropometric and spirometric evaluation was performed, as well as, on the same day, two TGlittre-P tests with a 30-minute interval between them.

RESULTS

TGlittre-P time test-retest reliability was excellent for both groups (CFG: intraclass correlation coefficient [ICC] = 0.849, p < 0.001 and HCG: ICC = 0.913, p < 0.001). As concerning absolute reliability, the time spent presented a small variability with a standard error of measurement of 8.4 s (s) to CFG and 5.3 s to HCG. The minimal detectable change at 95% confidence level (MDC95) was 23.2 s and 14.6 s, respectively. There was no difference between the groups regarding performance in the TGlittre-P test (CFG 179.1 s ± 25.7 s vs. HCG 174.7 s ± 22.3 s) p = 0.589.

CONCLUSION

The TGlittre-P is a reliable tool in children and adolescents with CF and healthy controls. The TGlittre-P appears not to be sensitive enough to discriminate a group of children and adolescents with mild cystic fibrosis from healthy counterparts.IMPLICATIONS FOR REHABILITATIONTGlittre-P is a multitasking test that has been used to assess the functional capacity of children and adolescents with chronic diseases.TGlittre-P has excellent reliability in children and adolescents with and without CF.TGlittre-P differences time greater than 12% could indicate changes in the functional capacity of children and adolescents with CF.Other functional capacity tests may be preferred to detect continuous increases in functional capacity through rehabilitation or training, whether children and adolescents obtain performance values close to 100% of predicted.

The modified shuttle test as a predictor of risk for hospitalization in youths with cystic fibrosis: A two-year follow-up study: Modified shuttle test as a predictor of hospitalization

BACKGROUND

Patients with cystic fibrosis (CF) present exercise intolerance and episodes of pulmonary exacerbations. This study aimed to evaluate the association of the distance covered on the modified shuttle test (MST), as well as other clinical variables (anthropometry, chronic colonization by Pseudomonas aeruginosa, lung function), with the risk of hospitalization for pulmonary exacerbation.

METHODS

Cohort study including CF patients older than 6 years, from two specialized CF centers. All patients underwent a MST and a lung function test at the time of inclusion. Demographic, anthropometric and clinical data were collected. Free time until the first hospitalization, total days of hospitalization and use of antibiotics during the two years of follow-up were recorded.

RESULTS

Sixty-seven patients with a mean (SD) age of 12.4 (5.2) years and forced expiratory volume in the first second (FEV₁) of 78.7% (22.4) were included. The mean distance covered (m) in the MST was 775.6 (255.7) (73.4 ± 19.5% of predicted). The distance achieved (MST) was considered as the main independent variable to predict the risk of hospitalization (Cox HR 0.97, p = 0.029). Patients who walked a distance of less than 80% of predicted in the MST showed an increase of 3.9 (95%CI 1.0-15.3) in the relative risk for hospitalization and significantly higher total number of days of hospitalization (p = 0.022).

CONCLUSION

There is an association between the distance covered in the MST and the risk of hospitalization in youths with CF. Patients with reduced exercise capacity presented a 3.9 times increase in the relative risk for hospitalization due to pulmonary exacerbation.

Effects of a long-term exercise program on motor performance in children and adolescents with CF

OBJECTIVES

The aim of this study was to examine motor performance and trainability in youths with cystic fibrosis (CF).

METHODS

Twenty-two children and adolescents (11 f/11 m), age range 6-17 years (11.3 ± 3.3 years), mean FEV1 91.0 ± 21.7% pred.finished the partially monitored 12-months exercise program. Patients performed the Deutsche Motorik Test (DMT) to assess flexibility, balance, strength, power and totalmotor performance. An incremental ergometer cycle test was used to assess maximal exercise capacity (Wpeak). All tests were performed before (T1), after 6 months of monitored exercise training (T3) and another 6 months without monitoring (T4).

RESULTS

Motor Competence in total and test-items of the DMT (except foreward bend) improved to T3 (p < .05). No further improvement could be observed after the end of the monitoring (T3). However, the values remained stable at the improved level (T4). Girls scored lower in test items depending on strength/power but scored higher in balancing compared to boys (p > .05). Wpeak and FEV1 were not influenced by the training program. From T3 to T4 a slight decrease was observed (p ≤ .05).

CONCLUSIONS

The findings demonstrate benefits of an individualizedmonitored long-term exercise intervention on motor performance in CF with improvements of test-tasks to predicted normal. Monitoringseems to be a facilitator in maintaining motivation toward physical activity as no further increase in motor performance was observed after stopping supervision. The results suggest that an individually tailored monitoredregular exercise program should include all aspects of physical fitness with a variety of movement experiences.

Youth with multiple sclerosis have low levels of fitness

Background:

Moderate and vigorous physical activity is associated with improved outcomes in youth with multiple sclerosis (MS). Physical fitness may also influence disease and health outcomes in this population.

Objectives:

To determine if there were differences in physical fitness between youth with MS and healthy controls (HC). To examine relationships between physical fitness, physical activity (PA) level, fatigue, depression and disease activity in youth with MS and HC.

Methods:

Youth with MS ( n = 19) and HC ( n = 21) completed tests establishing cardiorespiratory-fitness (VO2peak), endurance via 2-minute walk test, and musculoskeletal strength via grip strength (GS). Questionnaires determined fatigue, depression, and PA levels. Weekly PA level was determined by accelerometry. Tests of differences and correlational analyses were used to evaluate physical fitness.

Results:

Youth with MS had lower VO2peak ( U = 279, p < 0.0001), endurance ( t = 2.6, p = 0.02), and higher body mass index (BMI) ( t = -5.9, p = 0.001) than HC. Higher VO2peak was associated with higher moderate to vigorous PAaccelerometer in HC (Spearman-Rho = 0.5, p = 0.03), but not in youth with MS (Spearman-Rho = 0.5, p = 0.06). Lower VO2peak and GS were associated with higher disability (Spearman-Rho = -0.6, p = 0.03) and relapses in MS (Spearman-Rho = -0.52, p = 0.04).

Conclusions:

Youth with MS have lower levels of fitness, compared with HC. Higher levels of fitness were associated with lower disease activity and disability in youth with MS.

Physical exercise as a tool to minimize the consequences of the Covid-19 quarantine: An overview for cystic fibrosis

Coronavirus (SARS-CoV-2) outbreak leading to the coronavirus disease (Covid-19) has become a global pandemic. Patients with Cystic fibrosis are considered of major risk, as respiratory tract infections are more severe than in the general population, with a higher risk of complications and a negative impact on lung function. The performance of physical exercise is considered as key for its well-known general benefits and also as a complementary method to help airway clearance. Therefore, physical exercise is also considered as key in the therapeutic strategy during the quarantine period. However, the impossibility to perform exercise with appropriate prescription and monitoring is of considerable worry to health care professionals. Thus, alternative strategies, such as online measures to monitor this therapy and, consequently, to achieve a safe and effective dose are highly needed. Exercise regimens should include strength and endurance, as well as balance and flexibility exercises. Patients are highly encouraged to participate in exercise programs to maintain fitness and exercise should be continued during the quarantine period. This commentary provides a summary of the main effects and benefits of physical exercise, as well as the main recommendations for its adequate execution, including exercise modality, frequency, intensity, and volume.

EFFECTS OF PHYSICAL EXERCISE DURING HOSPITALIZATION IN CHILDREN AND ADOLESCENTS WITH CANCER: A SYSTEMATIC REVIEW

Objective:

To identify the effects of exercise programs during hospitalization on children and adolescents with cancer.

Data source:

This is a systematic review, carried out in PubMed/ Medical Literature Analysis and Retrieval System Online (MEDLINE), Latin American and Caribbean Health Sciences Literature (LILACS), Scientific Electronic Library Online (SciELO), Latin American and Caribbean Center on Health Sciences Information (BIREME), and Physiotherapy Evidence Database (PEDro). We selected studies that included children and adolescents diagnosed with cancer (solid or hematologic) and submitted to exercise protocols during hospitalization. Studies involving patients with other pathologies or with a medical contraindication for exercise were excluded. We used the following search strategy: Neoplasm OR Leukemia OR Cancer OR Tumor OR Medical Oncology AND Hospitalization OR Inpatient Care Units OR Intrahospital AND Exercise. The methodological quality of the studies was analyzed by the PEDro scale.

Data synthesis:

Among the 626 articles found, only 9 fulfilled the inclusion criteria, obtaining a regular methodological quality. The samples had 172 participants, aged 4 to 18 years. Only 6 studies presented both intervention group and control group. The intervention group received strength, aerobic, and muscle stretching exercises, and games, among others. The control group received the standard treatment. The studies varied regarding time, frequency, intensity, and type of exercise. Most studies showed an increase in muscle strength (4/5), followed by an improvement in physical fitness (2/3) and functional capacity (2/4). No adverse events were reported during the interventions. The methodological quality was considered regular.

Conclusions:

The findings suggest that. during hospitalization of children and adolescents with cancer, exercise improves muscle strength, physical fitness, and functionality.

Long-term effects of ivacaftor on nonpulmonary outcomes in individuals with cystic fibrosis, heterozygous for a S1251N mutation

OBJECTIVES

To describe the long-term effects of ivacaftor (Kalydeco®) in individuals with cystic fibrosis (CF) on body mass index (BMI), body composition (BC), pulmonary function (PF), resting energy expenditure (REE), and exercise capacity (EC) after ≥12 months of treatment.

WORKING HYPOTHESIS

BMI, lean and fat mass, PF, and EC will increase and REE will decrease after treatment.

STUDY DESIGN

Observational study.

METHODOLOGY

Seven individuals with CF (mean age 15.4 ± 5.8 years) heterozygous for S1251N mutation, starting with ivacaftor, were included. Paired t tests were performed to assess the effects of ivacaftor. Height and weight were used to calculate BMI and BMI Z-scores. Dual-energy X-ray absorptiometry was used to assess BC. Spirometry and body plethysmography were used to assess PF. Indirect calorimetry was used to measure REE and cardiopulmonary exercise testing (CPET) was used to measure oxygen uptake (VO_2peak ), peak work rate (W_peak ), and other CPET variables.

RESULTS

After a median of 15 (interquartile range: 13-16) months of treatment, BMI increased significantly (P = .03), but not BMI Z-score (P = .23) or BC. Significant improvements were found for several PF variables, especially measures of hyperinflation (P = .02). Absolute VO_2peak (P = .01), VO_2peak related to body weight (P = .00), and oxygen cost of work (P = .01) decreased. Absolute W_peak (P = .59) and W_peak related to body weight (P = .31) remained stable.

CONCLUSIONS

The results showed that long-term treatment of ivacaftor is associated with improvement of BMI and PF, but not of BC and REE. Oxygen uptake reduced after treatment, which may be due to a decrease in work of breathing.

High-intensity interval training accelerates oxygen uptake kinetics and improves exercise tolerance for individuals with cystic fibrosis

Background

Exercise training provides benefits for individuals with cystic fibrosis; however, the optimal program is unclear. High-intensity interval training is safe and effective for improving ‘functional capacity’ in these individuals with peak rate of O₂ uptake typically referenced. The ability to adjust submaximal rate of oxygen uptake (V̇O₂ kinetics) might be more important for everyday function because maximal efforts are usually not undertaken. Moreover, the ability of high-intensity training to accelerate V̇O₂ kinetics for individuals with cystic fibrosis could be enhanced with O₂ supplementation during training.

Methods

Nine individuals with cystic fibrosis completed incremental cycling to limit of tolerance followed by 8 weeks of high-intensity interval cycling (2 sessions per week x ~ 45 min per session) either with (n = 5; O2+) or without (AMB) oxygen supplementation (100%). Each session involved work intervals at 70% of peak work rate followed by 60 s of recovery at 35%. For progression, duration of work intervals was increased according to participant tolerance.

Results

Both groups experienced a significant increase in work-interval duration over the course of the intervention (O2+, 1736 ± 141 v. 700 ± 154 s; AMB, 1463 ± 598 v. 953 ± 253 s; P = 0.000); however, the increase experienced by O2+ was greater (P = 0.027). During low-intensity constant-work-rate cycling, the V̇O₂ mean response time was shortened post compared to pre training (O2+, 34 ± 11 v. 44 ± 9 s; AMB, 39 ± 14 v. 45 ± 17 s; P = 0.000) while during high-intensity constant-work-rate cycling, time to exhaustion was increased (O2+, 1628 ± 163 v. 705 ± 133 s; AMB, 1073 ± 633 v. 690 ± 348 s; P = 0.002) and blood [lactate] response was decreased (O2+, 4.5 ± 0.9 v. 6.3 ± 1.4 mmol^. L^− 1; AMB, 4.5 ± 0.6 v. 5.2 ± 1.4 mmol^. L^− 1; P = 0.003). These positive adaptations were similar regardless of gas inspiration during training.

Conclusion

Eight weeks of high-intensity interval training for patients with cystic fibrosis accelerated V̇O₂ kinetics and increased time to exhaustion. This provides some evidence that these patients may benefit from this type of exercise.

Trial registration

This study was retrospectively registered in the ISRTCN registry on 22/06/2019 (#ISRCTN13864650).

Physical activity and quality of life of children and adolescents with cystic fibrosis: a cross-sectional study

Abstract Introduction: Regular physical activity (PA) is part of outpatient care offered to most people with cystic fibrosis (CF). Objective: To determine the frequency of the self-reported PA and, secondarily evaluate associations between PA with clinical variables and health-related quality of life (HRQoL) in pediatric and adolescent CF subjects. Method: In this cross-sectional study, subjects between 6 and 17 years of age with a confirmed diagnosis of CF were recruited in the outpatient clinic. The subjects answered questions about the practices of PA, HRQoL questionnaire and clinical variables were collected. Subjects were classified into two groups according to weekly PA practice: PA performed ≥ 3 times/week and performed PA ≤ 2 times/week. Results: 66 subjects completed the study, 72.7% (n=48) had PA ≥ 3 times/week and 27.2% (n=18) had PA ≤ 2 times/week. Only twelve children (18,2%) reached the recommendations of the World Health Organization (WHO) to practice moderate to vigorous physical activities daily. The mean age of the subjects evaluated was 12.3 ± 3.2 years, forced expiratory volume in one second 90 ± 24.1% and forced vital capacity 95 ± 20.4%. The group that performed PA ≥ 3 times/week had a better clinical score (p=0.033), a lower number of hospitalizations in the year (p=0.002), a lower number of days hospitalized in the last year (p=0.020) and better score for the physical (p=0.003) and emotion (p=0.048) domains in HRQoL questionnaire. Conclusion: This study concluded that most subjects did not reach the WHO recommendations for the practice of PA. However, individuals who practice PA at least 3 times/week have better HRQoL, clinical score and fewer hospitalizations.

Effects of aerobic interval training on glucose tolerance in children and adolescents with cystic fibrosis: a randomized trial protocol

Background

Individuals with cystic fibrosis (CF) may develop CF-related diabetes (CFDR). This comorbidity is related to a poorer quality of life, microvascular complications, a decline in lung function, and an increase in exacerbations, as well as delayed growth and puberty. Evidence exists that physical exercise contributes to glycemic control in individuals with non-CF-related diabetes. This exercise is usually continuous with moderate intensity and long duration, which can cause muscle dyspnea and fatigue in CF individuals. Aerobic interval training (AIT) emerges as a safe and effective alternative for treating these individuals. The objective of this study is to evaluate the effects of AIT on glucose tolerance in children and adolescents with CF.

Methods

This study will be a two-arm, prospectively registered, randomized controlled trial with blind assessors and twenty 6- to 18-year-old individuals with cystic fibrosis (CF) from two different Brazilian states. People with CF will be randomly allocated to either the experimental or control group using block randomization, stratified by puberty stage,. Participants from both groups will receive an educational intervention and will be asked to continue their usual daily treatment for the full duration of the study. Those in the experimental group will perform AIT on a cycle ergometer at home three times a week, for 8 consecutive weeks. The sample characterization will include an assessment of puberty stage, socioeconomic status, dyspnea, and anthropometry. The primary outcome will be the change in glucose tolerance, while the secondary outcomes will include lung function, exercise tolerance, respiratory muscle strength, quality of life, and CF exacerbations. All outcomes will be assessed at baseline, week 9, and week 17.

Discussion

This is the first study to evaluate the effects of AIT on glucose tolerance in children and adolescents with CF. This study will serve as a basis for guiding clinical practice and decision-making in treating glucose intolerance and CF-related diabetes (CFRD) in children and adolescents with CF.

Trial registration

ClinicalTrials.gov Protocol Registration System: NCT03653949. Registered on August 31, 2018.

Comparison of the physiological responses induced by different pediatric exercise field tests in children

OBJECTIVE

This study aimed to compare the physiological responses induced by the modified shuttle walk test (MSWT), the 6-minute walk test (6MWT), and the pediatric Glittre activities of daily living test for children (TGlittre-P) in healthy children.

METHOD

This was an analytical observational cross-sectional study. All subjects underwent an anthropometric evaluation, pulmonary function test, TGlittre-P, 6MWT, and MSWT using a portable gas analyzer. Each test was conducted on the same day, and a maximum period of 15 days was considered for completion of the 3 days of data collection.

RESULTS

Overall, 24 subjects were included (mean age, 9.78 ± 1.27 years). The peak oxygen consumption (VO_2peak ) during the MSWT (1409.94 ± 285.13 mL/kg/min) was significantly higher than that during the TGlittre-P (982.19 ± 205.95 mL/kg/min) and 6MWT (982.85 ± 257.09 mL/kg/min) (P < .001 for both). There was no difference in VO_2peak  as well as most of the physiological variables between the 6MWT and TGlittre-P (P = .987). The MSWT VO_2peak correlated with the 6MWT VO_2peak (r = 0.67; P = .00) and the TGlittre-P VO_2peak (r = 0.43; P = .04). The VO_2peak values achieved in the 6MWT and TGlittre-P were also correlated (r = 0.68; P = .00). Unlike in the MSWT, in which the physiological measurements show an incremental response, the VO₂ , heart rate, minute ventilation, and respiratory exchange ratio were stabilized in the TGlittre-P and 6MWT.

CONCLUSION

The TGlittre-P and 6MWT showed similar physiological responses and required less metabolic, respiratory, and cardiovascular overload than the MSWT. The performance measures and VO_2peak values obtained in the three tests were correlated.

EXERCISE CAPACITY IN CHILDREN AND ADOLESCENTS WITH POST-INFECTIOUS BRONCHIOLITIS OBLITERANS: A SYSTEMATIC REVIEW

Objective:

To evaluate exercise capacity in children and adolescents with post-infectious bronchiolitis obliterans.

Data source:

This is a systematic review based on data from PubMed, Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS), Scientific Electronic Library Online (SciELO), and Physiotherapy Evidence Database (PEDro). We used the following search strategy: “Exercise capacity OR Exercise Test OR Physical fitness OR Functional capacity OR Six-minute walk test OR Shuttle walk test OR Cardiopulmonary exercise test AND Bronchiolitis obliterans.” We selected studies that evaluated exercise capacity through maximal/submaximal testing in children and adolescents with post-infectious bronchiolitis obliterans, and no other associated disease. We searched articles in English, Portuguese, and Spanish, without restrictions regarding the period of publication. The methodological quality was assessed by the Agency for Healthcare Research and Quality (AHRQ) protocol.

Data synthesis:

Out of the 81 articles found, only 4 were included in this review. The studies totaled 135 participants (121 with post-infectious bronchiolitis obliterans and 14 healthy), with sample sizes between 14 and 58 subjects. All patients underwent spirometry to evaluate pulmonary function, indicating an obstructive ventilatory pattern. Among them, 3/4 had their physical performance assessed by the six-minute walk test and 2/4 by the cardiopulmonary exercise testing. These test results were compared to those of a control group (1/4) and presented as percentage of predicted and/or in meters (3/4). Lastly, 3/4 of the studies showed reduced exercise capacity in this population. The studies included were classified as having high methodological quality.

Conclusions:

Findings of the study demonstrate that children and adolescents with post-infectious bronchiolitis obliterans have reduced exercise capacity.

Cardiopulmonary responses to maximal aerobic exercise in patients with cystic fibrosis

Cystic fibrosis (CF) is a debilitating chronic condition, which requires complex and expensive disease management. Exercise has now been recognised as a critical factor in improving health and quality of life in patients with CF. Hence, cardiopulmonary exercise testing (CPET) is used to determine aerobic fitness of young patients as part of the clinical management of CF. However, at present there is a lack of conclusive evidence for one limiting system of aerobic fitness for CF patients at individual patient level. Here, we perform detailed data analysis that allows us to identify important systems-level factors that affect aerobic fitness. We use patients’ data and principal component analysis to confirm the dependence of CPET performance on variables associated with ventilation and metabolic rates of oxygen consumption. We find that the time at which participants cross the gas exchange threshold (GET) is well correlated with their overall performance. Furthermore, we propose a predictive modelling framework that captures the relationship between ventilatory dynamics, lung capacity and function and performance in CPET within a group of children and adolescents with CF. Specifically, we show that using Gaussian processes (GP) we can predict GET at the individual patient level with reasonable accuracy given the small sample size of the available group of patients. We conclude by presenting an example and future perspectives for improving and extending the proposed framework. The modelling and analysis have the potential to pave the way to designing personalised exercise programmes that are tailored to specific individual needs relative to patient’s treatment therapies.

Current perspectives of physical activity in cystic fibrosis

Introduction: Regular exercise and physical activity participation are recommended in guideline-based care for individuals with cystic fibrosis (CF) across the spectrum of age and disease severity. However, the best training methods to improve physical function and encourage ongoing exercise and activity participation are not clear, which is an ongoing challenge for clinicians. Areas covered: This perspective provides an overview of current evidence for exercise and physical activity relative to clinical outcomes and health-care utilization in people with CF, and highlights areas of future research need. Expert commentary: What kind, how much, how often, and how best to support people with CF to be physically active is uncertain. Whether new methods of training, the use of technology, or pharmaceutical developments could best deliver increased activity and physiological benefit without increased therapeutic burden is unclear. At present, if people with CF are going to be physically active, seemingly they should aim to perform this activity in the way most likely to confer some health benefit i.e. concerted exercise bouts of at least 10 min in addition to any incidental (habitual) activity performed during the course of daily life.

Effects of high intensity interval training on exercise capacity in people with cystic fibrosis: study protocol for a randomised controlled trial

BACKGROUND

In people with cystic fibrosis (CF), higher exercise capacity is associated with better health-related quality of life (HRQoL), reduced risk of hospitalisation for a respiratory infection and survival. Therefore, optimisation of exercise capacity is an important treatment goal. The Australian and New Zealand clinical practice guidelines recommend that people with CF complete 30 to 60 min of moderate intensity aerobic exercise on most days of the week. This recommendation can be difficult to achieve by people with CF because of time constraints, and intolerable breathlessness and muscle fatigue during continuous exercise. In contrast, a low-volume, high intensity interval training (HIIT) program may be a more achievable and efficient training method to improve exercise capacity in people with CF.

METHODS

A randomised controlled trial will be undertaken. Forty people with CF (aged ≥15 years) will be randomly allocated, on a 1:1 ratio, to either the experimental or control group. Regardless of their group allocation, all participants will be asked to continue with their usual daily treatment for the study duration. Those in the experimental group will complete 8 weeks of thrice weekly HIIT on a cycle ergometer. Those in the control group will receive weekly contact with the investigators. The primary outcome of this study is exercise capacity. Secondary outcomes are HRQoL, exercise self-efficacy, feelings of anxiety, depression and enjoyment. These outcomes will be recorded at baseline (i.e. prior to randomisation) and following the 8-week intervention period. The study will also report other outcomes of the HIIT program (cardiovascular responses, symptom response, post-exercise muscle soreness and tolerance) and behaviour change techniques such as reinforcement, feedback and goal setting, used during the HIIT program.

DISCUSSION

This study will determine the effects of 8-weeks of supervised, low-volume HIIT, completed on a cycle ergometer on measures of exercise capacity, HRQoL, exercise self-efficacy, feelings of anxiety, depression and enjoyment. If effective, this type of training could be an attractive alternative to traditional continuous training because it may be more achievable and time efficient.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry (ANZCTR):12617001271392 (04/09/2017).

Sildenafil improves vascular endothelial function in patients with cystic fibrosis

Cystic fibrosis (CF), characterized by defective CFTR function, is associated with multiple systemic complications, including vascular dysfunction. Sildenafil, a phosphodiesterase type 5 inhibitor, not only enhances nitric oxide (NO) metabolism but has been shown to improve CFTR functionality as well. Thus, sildenafil has been proposed as a therapy to improve vascular health in CF; however, its potential therapeutic role has yet to be determined. We sought to investigate the effect of sildenafil on endothelial function in patients with CF. Patients with CF completed a randomized, double-blind, placebo-controlled, crossover study with an acute dose of sildenafil (50 mg) or placebo followed by a 4-wk open-label extension with sildenafil (20 mg/day). Flow-mediated dilation (FMD) was used to evaluate endothelial function before and after treatments. In addition, phosphorylated endothelial NO synthase (pNOS3) and total NOS3 protein expression was determined from endothelial cells that were exposed to plasma from the patients before and after 4 wk of sildenafil treatment. No changes ( P ≥ 0.110) in endothelial function were observed after the acute dose of sildenafil. However, FMD significantly ( P = 0.029) increased after 4 wk of treatment (∆FMD: 1.5 ± 2.2%). Moreover, pNOS3 protein expression significantly ( P = 0.013) increased after 4 wk of treatment (∆pNOS3: 0.31 ± 0.39 arbitrary units) and was associated ( r = 0.593, P = 0.033) with the change in FMD. These data suggest that 4 wk of sildenafil treatment can improve vascular endothelial function in patients with CF, likely through an increase in NOS3 phosphorylation. NEW & NOTEWORTHY Findings from the present study demonstrate, for the first time, significant improvement of endothelial function in patients with cystic fibrosis treated with sildenafil that is associated with greater phosphorylation of endothelial nitric oxide synthase. These results support the use of sildenafil as a potential novel therapy for this patient population.

Cardiopulmonary exercise testing with supramaximal verification produces a safe and valid assessment of V̇o2max in people with cystic fibrosis: a retrospective analysis

The validity and safety of using supramaximal verification (S_max) to confirm a maximal effort during cardiopulmonary exercise testing (CPET) in people with cystic fibrosis (CF) and/or those with severe disease has been questioned. Therefore, this study aimed to investigate these concerns in children, adolescents, and adults with mild-to-severe CF lung disease. Retrospective analysis of 17 pediatric and 28 adult participants with CF [age range: 9.2-62.9 y; forced expiratory volume in 1 s: 66.7% (range: 29.9%-102.3%); 30 men] who completed a routine ramp-incremental cycling test to determine peak oxygen uptake (V̇o_2peak) was studied. Maximal oxygen uptake (V̇o_2max) was subsequently confirmed by S_max at 110% of peak power output. All participants satisfied the criteria to verify a maximal effort during CPET. However, S_max-V̇o_2peak exceeded ramp-V̇o_2peak in 3/14 (21.4%) of pediatric and 6/28 (21.4%) adult exercise tests. A valid measurement of V̇o_2max was attained in 85.7% of pediatric and 96.4% of adult exercise tests, as S_max-V̇o_2peak did not exceed ramp-V̇o_2peak by >9%. Adults ( n = 9) experienced a ≥5% reduction in arterial O₂ saturation during CPET, 4 during both the ramp and S_max, 3 during only the ramp, and 2 during only S_max. S_max did not significantly worsen perceived breathing effort, chest tightness, throat narrowing, or exertion compared with ramp-incremental testing. Given the clinical importance of aerobic fitness in people with CF, incorporating S_max is recommended to provide a safe and valid measure of V̇o_2max in children, adolescents, and adults who span the spectrum of CF disease severity. NEW & NOTEWORTHY Incorporating supramaximal verification into cardiopulmonary exercise testing protocols did not increase the frequency of adverse events or perceived discomfort versus a single-phase incremental exercise test in people with mild-to-severe cystic fibrosis. Furthermore, a valid measure of maximal oxygen uptake (V̇o_2max) was obtained from 85.7% of pediatric and 96.4% of adult exercise tests, whereas peak oxygen uptake underestimated aerobic fitness in comparison with V̇o_2max in 21.4% of cases (by up to 24.4%).

Analysis of oxygen uptake efficiency parameters in young people with cystic fibrosis

PURPOSE

This study characterised oxygen uptake efficiency (OUE) in children with mild-to-moderate cystic fibrosis (CF). Specifically, it investigated (1) the utility of OUE parameters as potential submaximal surrogates of peak oxygen uptake ([Formula: see text]), and (2) the relationship between OUE and disease severity.

METHODS

Cardiopulmonary exercise test (CPET) data were collated from 72 children [36 CF, 36 age- and sex-matched controls (CON)], with OUE assessed as its highest 90-s average (plateau; OUEP), the gas exchange threshold (OUE_GET) and respiratory compensation point (OUE_RCP). Pearson's correlation coefficients, independent t tests and factorial ANOVAs assessed differences between groups and the use of OUE measures as surrogates for [Formula: see text].

RESULTS

A significant (p < 0.05) reduction in allometrically scaled [Formula: see text] and all OUE parameters was found in CF. Significant (p < 0.05) correlations between measurements of OUE and allometrically scaled [Formula: see text], were observed in CF (r = 0.49-0.52) and CON (r = 0.46-0.52). Furthermore, measures of OUE were significantly (p < 0.05) correlated with pulmonary function (FEV_1%predicted) in CF (r = 0.38-0.46), but not CON (r = -0.20-0.14). OUEP was able to differentiate between different aerobic fitness tertiles in CON but not CF.

CONCLUSIONS

OUE parameters were reduced in CF, but were not a suitable surrogate for [Formula: see text]. Clinical teams should, where possible, continue to utilise maximal CPET parameters to measure aerobic fitness in children and adolescents with CF. Future research should assess the prognostic utility of OUEP as it does appear sensitive to disease status and severity.

Scaling the Oxygen Uptake Efficiency Slope for Body Size in Cystic Fibrosis

PURPOSE

The aim of this study was to describe the relationship between body size and oxygen uptake efficiency slope (OUES) in pediatric patients with cystic fibrosis (CF) and healthy controls (CON), to identify appropriate scaling procedures to adjust the influence of body size upon OUES.

METHODS

The OUES was derived using maximal and submaximal points from cardiopulmonary exercise testing in 72 children (36 CF and 36 CON). OUES was subsequently scaled for stature, body mass (BM), and body surface area (BSA) using ratio-standard (Y/X) and allometric (Y/X) methods. Pearson's correlation coefficients were used to determine the relationship between body size and OUES.

RESULTS

When scaled using the ratio-standard method, OUES had a significant positive relationship with stature (r = 0.54, P < 0.001) and BSA (r = 0.25, P = 0.031) and significant negative relationship with BM (r = -0.38, P = 0.016) in the CF group. Combined allometric exponents (b) for CF and CON were stature 3.00, BM 0.86, and BSA 1.40. A significant negative correlation was found between OUES and stature in the CF group when scaled allometrically (r = -0.37, P = 0.027). Nonsignificant (P > 0.05) correlations for the whole group were found between OUES and allometrically scaled BM (CF r = -0.25, CON, r = 0.15) and BSA (CF r = -0.27, CON r = 0.13).

CONCLUSIONS

Only allometric scaling of either BM or BSA, and not ratio-standard scaling, successfully eliminates the influence of body size upon OUES. Therefore, this enables a more direct comparison of the OUES between patients with CF and healthy controls.

Relationship between exercise capacity and glucose tolerance in cystic fibrosis

BACKGROUND

Improved exercise capacity (EC) and normal glucose tolerance (NGT) are independently associated with favorable outcomes in CF, however, little information on this relationship exists in patients with CF.

METHODS

Cardiopulmonary exercise tests, oral glucose tolerance tests (OGTT), and HbA1c values measured within a 12-month period were evaluated on 83 pediatric patients diagnosed with CF. Patients were categorized as having NGT, abnormal glucose tolerance (AGT), or CF-related diabetes (CFRD).

RESULTS

EC decreased as severity of glucose intolerance increased across NGT, AGT, and CFRD groups (P = 0.02). Compared to patients with NGT, patients with CFRD had lower peak VO₂ mL/kg/min (33.0 ± 7.3 vs 41.3 ± 9.4, P = 0.01), lower VO₂ % (81 ± 20 vs 93 ± 17, P = 0.03), and higher HbA1c (6.9 ± 1.7 vs 5.4 ± 0.4, P < 0.01). There was a positive association with age and FEV₁ % with EC in the 17 patients with CFRD. In the 66 patients without diabetes, peak EC was positively associated with FEV₁ % and negatively associated with age, fasting insulin, and insulin 120 min. After accounting for age and FEV₁ %, multivariate analyses indicated that insulin and glucose values at 120 min predicted EC.

CONCLUSIONS

These data provide evidence that poor glucose tolerance is associated with lower EC in pediatric patients with CF. There was a significant relationship between glucose and insulin values obtained by OGTT with EC in a sample of non-diabetic patients with preserved lung function. Future studies are warranted to confirm these findings and investigate the potential role of exercise in the management or prevention of CFRD.

The oxygen uptake efficiency slope is not a valid surrogate of aerobic fitness in cystic fibrosis

BACKGROUND

Maximal cardiopulmonary exercise testing is recommended on an annual basis for children with cystic fibrosis (CF), due to clinically useful prognostic information provided by maximal oxygen uptake (V̇O_2max ). However, not all patients are able, or willing, to reach V̇O_2max , and therefore submaximal alternatives are required. This study explored the validity of the oxygen uptake efficiency slope (OUES) as a submaximal measure of V̇O_2max in children and adolescents with CF.

METHODS

Data were collated from 72 cardiopulmonary exercise tests (36 CF, 36 controls), with OUES determined relative to maximal and submaximal parameters of exercise intensity, time, and individual metabolic thresholds. Pearson's correlation coefficients, independent t-tests, and factorial ANOVAs were used to determine validity.

RESULTS

Significant (P < 0.05) correlations with V̇O_2max were observed for most expressions of OUES, but were consistently weaker in CF (r = 0.30-0.47) when compared to CON (r = 0.58-0.89). Mean differences for all OUES parameters between groups were not significant (P > 0.05). When split by V̇O_2max tertiles, minimal significant differences were found between, and within, groups for OUES, indicating poor discrimination of V̇O_2max .

CONCLUSIONS

The OUES is not a valid (sub) maximal measure of V̇O_2max in children and adolescents with mild-to-moderate CF. Clinicians should continue to use maximal markers (ie, V̇O_2max ) of exercise capacity.

Exercise performance and quality of life in children with cystic fibrosis and mildly impaired lung function: relation with antibiotic treatments and hospitalization

This study evaluates the impact of antibiotic treatments and hospitalization on exercise performance and health-related quality of life (QOL) in children with mild cystic fibrosis (CF) lung disease. Forty-seven children between 7 and 17 years with mild CF underwent a maximal exercise test including spiro-ergometry and filled out a QOL-questionnaire (PedsQL™). Amount of antibiotic treatments (AB) and hospitalization days in the last 3 years were reviewed. FEV1% was mildly decreased (91.7 ± 17.9 L/min, p = 0.02). Maximal oxygen consumption (VO₂max), test duration and anaerobic threshold were lower compared to a control population (VO₂max% 94 ± 15 vs 103 ± 13, p = 0.009). FEV1% correlated with AB and hospitalization episodes in the last year and 3 years before testing, VO₂max% only correlated with AB in the last 3 years. Domains of school functioning and emotional functioning were low. Children with higher VO₂max% and less AB in the last 3 years had better physical health. Physical health and school functioning were negatively correlated with hospitalization days in the last year.

CONCLUSION

Patients with mild CF lung disease have good exercise performance although still lower than the normal population. VO2max% is affected by number of antibiotic treatments over a longer period. There is an impact of hospitalization days on quality of life. What is Known: • Children with CF have lower exercise performance; there is an association between hospitalization frequency and exercise performance • Quality of life is diminished in children with CF and influenced by respiratory infections What is New: • Even patients with mild CF lung disease have lower maximal exercise performance (VO ₂ max) and a lower anaerobic threshold; VO ₂ max is lower in children who had more antibiotic treatments in the last 3 years • School and emotional functioning are diminished in children with mild CF lung disease; hospitalization is negatively correlated with school functioning and physical functioning.

Functional Capacity in Congenital Heart Disease: A Systematic Review and Meta-Analysis

Background

Children and adolescents with congenital heart disease often have alterations in their exercise capacity that can be evaluated by various functional testing.

Objective

To evaluate the functional capacity of children and adolescents with congenital heart disease (CHD) with systematic review and meta-analyses.

Methods

The review included observational studies, data from the first evaluation of randomized clinical trials or observational follow-up periods after clinical trials which evaluated functional capacity by cardiopulmonary exercise test, stress testing, six-minute walk test or step test, in children and adolescents with CHD, aged between six and 18 years, and comparisons with healthy controls in the same age group. The quantitative assessment was performed by meta-analysis, by comparing the maximal oxygen consumption (VO₂max) of children and adolescents with CHD and respective control groups.

Results

Twenty-five of 2.683 studies identified in the search met the inclusion criteria. The VO₂max measurement showed that patients with CHD have a decrease of 9.31 ml/Kg/min (95% CI. -12.48 to -6.13; I², 94.3%, P for heterogeneity < 0.001) compared with the control group. The meta-analysis of the data of maximum heart rate (HR) reached during cardiopulmonary test and stress testing, retrieved from 18 studies, showed a HR value of -15.14 bpm (95% CI. -20.97 to -9.31; I², 94.3%, P for heterogeneity < 0.001) compared with the control group.

Conclusion

Children and adolescents with CHD have lower VO₂max and HR compared to controls.

A single bout of maximal exercise improves lung function in patients with cystic fibrosis

BACKGROUND

Responses to a single bout of exercise may provide critical information for maximizing improvements in pulmonary function following exercise training in cystic fibrosis (CF). We sought to determine if acute maximal exercise improves pulmonary function in patients with CF.

METHODS

Thirty-three patients with CF completed a comprehensive assessment of pulmonary function to determine forced vital capacity (FVC), forced expiratory volume in one second (FEV₁), and lung clearance index (LCI) prior to and immediately following maximal aerobic exercise on a cycle ergometer.

RESULTS

Following exercise, FVC (∆0.08±0.14L) and FEV₁ (∆0.06±0.15L) increased, while LCI decreased (∆-0.71±0.93) (all p<0.05). Changes in FEV₁ (%predicted) were associated with peak work (r=0.40, p=0.02) and peak pulmonary ventilation (r=0.45, p=0.01).

CONCLUSIONS

A single bout of maximal exercise acutely improves pulmonary function in patients with CF and improvements may be related to peak work and peak pulmonary ventilation.

Six-Minute Walk Test Results Predict Risk of Hospitalization for Youths with Cystic Fibrosis: A 5-Year Follow-Up Study

OBJECTIVE

To evaluate the association of 6-minute walk test (6MWT) and other variables (anthropometry, chronic Pseudomonas aeroginosa colonization, pulmonary function, and respiratory muscle strength) with the risk of hospitalization for pulmonary exacerbation in children and adolescents with cystic fibrosis (CF).

STUDY DESIGN

Cohort study that included patients with CF aged 6-18 years. All participants underwent spirometry, manovacuometry, and 6MWT during the 5-year follow-up. Anthropometric and clinical data were collected and the time to first hospitalization, total days of hospitalization, and antibiotic use during follow-up was recorded.

RESULTS

A total of 26 patients with CF, mean age 10.2 ± 2.8 years, were included. The group had mild impairment of lung function with a significant decline in forced expiratory volume in 1 second (P = .019) over the 5 years. Respiratory muscle strength and 6MWT proved to be preserved, although maximum inspiratory pressure increased (P < .001) and maximum expiratory pressure and 6-minute walk distance (6MWD) remained stable. There were inverse associations of 6MWD in meters (r = -0.813, P < .001) and z score (r = -0.417, P = .015) with total days of hospitalization. Moreover, there was a reduction in the risk of a first hospitalization (Cox HR 0.32; P = .037) in patients with a greater 6MWD.

CONCLUSIONS

We found an association between the 6MWT and the risk of hospitalization in children and adolescents with CF. Furthermore, functional capacity apparently does not follow the expected decline in pulmonary function over time, whereas inspiratory muscle strength increases with disease progression.

Physiological markers of exercise capacity and lung disease severity in cystic fibrosis

BACKGROUND AND OBJECTIVE

Peak aerobic capacity (VO₂ peak) is an important outcome measure in cystic fibrosis (CF), but measurement is not widely available and can be influenced by patient motivation, pain and fatigue. Alternative markers of disease severity would be helpful. Neural respiratory drive, measured using parasternal intercostal muscle electromyography (EMGpara), reflects the load to capacity balance of the respiratory system and provides a composite measure of pulmonary function impairment in CF. The aim of the study was to investigate the relationship between exercise capacity, EMGpara and established measures of pulmonary function in clinically stable adult CF patients.

METHODS

Twenty CF patients (12 males, median (range) age: 22.3 (17.0-43.1) years) performed the 10-m incremental shuttle walk test (ISWT) maximally with contemporaneous measures of aerobic metabolism. EMGpara was recorded from second intercostal space at rest and normalized using peak electromyogram activity obtained during maximum respiratory manoeuvres and expressed as EMGpara%max (EMGpara expressed as a percentage of maximum).

RESULTS

VO₂ peak was strongly correlated with ISWT distance (r = 0.864, P < 0.0001). Lung gas transfer (T_L CO) % predicted was best correlated with VO₂ peak (r = 0.842, P < 0.0001) and ISWT distance (r = 0.788, P < 0.0001). EMGpara%max also correlated with VO₂ peak (-0.757, P < 0.0001), while the relationships between exercise outcome measures and forced expiratory volume in 1 s (FEV₁ ) % predicted and forced vital capacity (FVC) % predicted were less strong. A T_L CO% predicted of <70.5% was the strongest predictor of VO₂ peak <32 mL/min/kg (area under the curve (AUC): 0.96, 100% sensitivity, 83.3% specificity). ISWT distance and EMGpara%max also performed well, with other pulmonary function variables demonstrating poorer predictive ability.

CONCLUSION

T_L CO% predicted and EMGpara%max relate strongly to exercise performance markers in CF and may provide alternative predictors of lung disease progression.

Exercise capacity following a percutaneous endoscopic gastrostomy in a young female with cystic fibrosis: a case report

Cystic fibrosis (CF) is a genetic condition affecting the respiratory and gastrointestinal systems, with patients experiencing problems maintaining weight, especially during rapid growth periods such as puberty. The aim of this case report was to monitor the effect of gastrostomy insertion and implementation of overnight supplemental feeding upon clinical outcomes, including body mass index (BMI), lung function (FEV₁), and exercise‐related variables (maximal oxygen uptake [VO_2max] and ventilatory efficiency [V_E/VO₂]) in an 11‐year‐old female with CF. Combined incremental and supramaximal exercise testing to exhaustion was performed at four time points: 3 months prior to the procedure (T1), 2 days prior to (T2), 4 months (T3), and 1 year following the procedure (T4). Improvements following gastrostomy insertion were observed at the 1 year follow‐up with regards to BMI (+20%); whereas absolute VO_2max remained stable and lung function fluctuated throughout the period of observation. Declines in function with regards to body weight relative VO_2max (−16.3%) and oxygen uptake efficiency (+7.5%) were observed during this period. This case report is the first to consider exercise‐related clinical outcomes in assessing the effect of implementing gastrostomy feeding in CF. The varied direction and magnitude of the associations between variables shows that further investigations are required.