Clinical interpretation of cardiopulmonary exercise testing in cystic fibrosis and implications for exercise counselling

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.

Effect of Menstrual Cycle Phase on the Recovery Process of High-Intensity Interval Exercise-A Cross-Sectional Observational Study

Although the study of the menstrual cycle influence on endurance exercise has recently increased, there is a lack of literature studying its influence on females' cardiorespiratory recovery. Thus, the aim of the present work was to assess menstrual cycle influence on post-exercise recovery following a high intensity interval exercise in trained females. Thirteen eumenorrheic endurance-trained females performed an interval running protocol in three menstrual cycle phases: early follicular phase (EFP), late follicular phase (LFP), and mid-luteal phase (MLP). The protocol consisted of 8 × 3-min bouts at 85% of their maximal aerobic speed (vVO2peak) with a 90-s rest between bouts and a final 5-min active recovery at 30% vVO2peak. All variables were averaged every 15 s, obtaining 19 moments during recovery (time factor). To analyze the effects of the menstrual cycle on the final active cardiorespiratory recovery, an ANOVA for repeated measures was performed. ANOVA showed an effect on menstrual cycle phase on ventilation (EFP: 1.27 ± 0.35; LFP: 1.19 ± 0.36; MLP: 1.27 ± 0.37), breathing frequency (EFP: 35.14 ± 7.14; LFP: 36.32 ± 7.11; MLP: 37.62 ± 7.23), and carbon dioxide production (EFP: 1120.46 ± 137.62; LFP: 1079.50 ± 129.57; MLP: 1148.78 ± 107.91). Regarding the interaction results (phase x time), ventilation is higher at many of the recovery times during the MLP, with less frequent differences between EFP and LFP (F = 1.586; p = 0.019), while breathing reserve is lower at many of the recovery times during MLP, with less time differences between EFP and LFP (F = 1.643; p = 0.013). It seems that the menstrual cycle affects post-exercise recovery specially during the MLP, rising ventilation and lowering breathing reserve, giving rise to an impaired ventilatory efficiency.

Relationship between peripheral muscle strength, exercise capacity and body composition in children and adolescents with cystic fibrosis

STUDY DESIGN

This was a transversal analytical study.

BACKGROUND

Exercise capacity is usually decreased in cystic fibrosis, impacting the disease prognosis. As well, peripheral muscle strength and nutritional status seem to be related to exercise capacity (EC).

OBJECTIVE

To verify the relationship between peripheral muscle strength, pulmonary function and body composition with EC in children and adolescents with CF.

METHODS

The study included CF children/adolescents that were clinically stable. The disease's severity was classified according to the Schwachman-Doerschuk score. Initially the subjects underwent bioimpedance and spirometry tests. Quadriceps muscle strength (QMS) and handgrip strength (HG) were evaluated by dynamometry. The Modified Shuttle Walk Test (MSWT) was conducted along with gas analysis in order to measure EC.

RESULTS

Twenty-five children/adolescents (10.30 ± 2.33 years old) participated in the survey. 72% were eutrophic, with a mean FEV1 of 68.55%, predicted percentage of the MSWT walked distance (%WD) was 70.91%, and QMS 65.80%. QMS presented significant correlations with absolute WD (r = 0.54), oxygen peak consumption (r = 0.72), lean body mass (LM) (r = 0.83), and body mass index (BMI) (r = 0.69). HG was related with BMI (r = 0.45) and LM (r = 0.65). There was a difference in the %WD between the groups with higher/lower strength (p = .02).

CONCLUSION

There was no correlation between HG and EC in this studied sample. Early involvement of QMS was observed even in individuals with low disease severity. This finding reinforces the importance of including this QMS assessment in CF reference centers to monitor, prevent and prescribe adequate exercise training for these individuals.

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.

Asthma, body mass and aerobic fitness, the relationship in adolescents: The exercise for asthma with commando Joe's® (X4ACJ) trial

Although an association has been suggested between asthma, obesity, fitness and physical activity, the relationship between these parameters remains to be elucidated in adolescents. Six-hundred and sixteen adolescents were recruited (334 boys; 13.0 ± 1.1years; 1.57 ± 0.10m; 52.6 ± 12.9kg), of which 155 suffered from mild-to-moderate asthma (78 boys). Participants completed a 20-metre shuttle run test, lung function and 7-day objective physical activity measurements and completed asthma control and quality of life questionnaires. Furthermore, 69 adolescents (36 asthma; 21 boys) completed an incremental ramp cycle ergometer test. Although participants with asthma completed significantly fewer shuttle runs than their peers, peak V̇O₂ did not differ between the groups. However, adolescents with asthma engaged in less physical activity (53.9 ± 23.5 vs 60.5 ± 23.6minutes) and had higher BMI (22.2 ± 4.8 vs 20.4 ± 3.7kg·m-2), than their peers. Whilst a significant relationship was found between quality of life and cardiorespiratory fitness according to peak V̇O₂, only BMI was revealed as a significant predictor of asthma status. The current findings highlight the need to use accurate measures of cardiorespiratory fitness rather than indirect estimates to assess the influence of asthma during adolescence. Furthermore, the present study suggests that BMI and fitness may be key targets for future interventions seeking to improve asthma quality of life.

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.

Increased physical activity post-exacerbation is associated with decreased systemic inflammation in cystic fibrosis - An observational study

Background and Objective: We assessed whether measured physical activity in adults with cystic fibrosis (CF) following in-hospital treatment for an acute exacerbation was impacted by levels of systemic and airway inflammation, and whether physical activity post-discharge predicted for time to next pulmonary exacerbation. Methods: Adults with CF were included following hospitalization for a pulmonary exacerbation, and were followed for 12 months. Inflammatory markers and physical activity were measured immediately post-discharge via sputum and plasma concentrations of interleukin-6, interleukin-8, and tumor necrosis factor-α. Physical activity was monitored for 7 days via a Sensewear Armband. Statistical analyses included Shapiro-Wilk's test and Q-Q plots to determine normal distribution, t-tests, Pearson's correlational analyses, and one-way MANOVAs. Results: Thirty-one adults with CF (13 females, 28.8 ± 8.8 years, forced expiratory volume in 1 s (FEV₁) 59.4 ± 23.0% predicted) were prospectively recruited. Physical activity negatively correlated with plasma inflammation (r = -0.48, p < 0.01), and positively with FEV₁ (r = 0.45, p < 0.05) and body mass index (r = 0.39, p < 0.05). There was no significant relationship between time to re-exacerbation and any inflammatory markers or measurement of physical activity (all p > 0.05). Conclusion: Increased physical activity following exacerbation in CF is associated with lower levels of systemic inflammation. Time to re-exacerbation is not related to post-discharge inflammation or physical activity levels.