Effects of a Partially Supervised Conditioning Program in Cystic Fibrosis: An International Multicenter, Randomized Controlled Trial (ACTIVATE-CF).

Rationale: The long-term effects of vigorous physical activity (PA) on lung function in cystic fibrosis are unclear. Objectives: To evaluate effects of a 12-month partially supervised PA intervention using motivational feedback. Methods: In a parallel-arm multicenter randomized controlled trial (ACTIVATE-CF), relatively inactive patients aged at least 12 years were randomly assigned (1:1 ratio) to an intervention group or control group. The intervention group consented to add 3 hours of vigorous PA per week, whereas the control group was asked not to change their PA behavior. Primary endpoint was change in percent predicted FEV1 (ΔFEV1) at 6 months. Secondary endpoints included PA, exercise capacity, exercise motives, time to first exacerbation and exacerbation rates, quality of life, anxiety, depression, stress, and blood glucose control. Data were analyzed using mixed linear models. Measurements and Main Results: A total of 117 patients (40% of target sample size) were randomized to an intervention (n = 60) or control group (n = 57). After 6 months, ΔFEV1 was significantly higher in the control group compared with the intervention group (2.70% predicted [95% confidence interval, 0.13-5.26]; P = 0.04). The intervention group reported increased vigorous PA compared with the control group at each study visit, had higher exercise capacity at 6 and 12 months, and higher PA at 12 months. No effects were seen in other secondary outcomes. Conclusions: ACTIVATE-CF increased vigorous PA and exercise capacity, with effects carried over for the subsequent 6 months, but resulted in better FEV1 in the control group.

Effects of an Antioxidant-enriched Multivitamin in Cystic Fibrosis. A Randomized, Controlled, Multicenter Clinical Trial.

RATIONALE: Cystic fibrosis (CF) is characterized by dietary antioxidant deficiencies, which may contribute to an oxidant-antioxidant imbalance and oxidative stress. OBJECTIVES: Evaluate the effects of an oral antioxidant-enriched multivitamin supplement on antioxidant concentrations, markers of inflammation and oxidative stress, and clinical outcomes. METHODS: In this investigator-initiated, multicenter, randomized, double-blind, controlled trial, 73 pancreatic-insufficient subjects with CF 10 years of age and older with an FEV1 between 40% and 100% predicted were randomized to 16 weeks of an antioxidant-enriched multivitamin or control multivitamin without antioxidant enrichment. Endpoints included systemic antioxidant concentrations, markers of inflammation and oxidative stress, clinical outcomes (pulmonary exacerbations, anthropometric measures, pulmonary function), safety, and tolerability. MEASUREMENTS AND MAIN RESULTS: Change in sputum myeloperoxidase concentration over 16 weeks, the primary efficacy endpoint, was not significantly different between the treated and control groups. Systemic antioxidant (ß-carotene, coenzyme Q10, γ-tocopherol, and lutein) concentrations significantly increased in the antioxidant-treated group (P < 0.001 for each), whereas circulating calprotectin and myeloperoxidase decreased in the treated group compared with the control group at Week 4. The treated group had a lower risk of first pulmonary exacerbation requiring antibiotics than the control group (adjusted hazard ratio, 0.50; P = 0.04). Lung function and growth endpoints did not differ between groups. Adverse events and tolerability were similar between groups. CONCLUSIONS: Antioxidant supplementation was safe and well tolerated, resulting in increased systemic antioxidant concentrations and modest reductions in systemic inflammation after 4 weeks. Antioxidant treatment was also associated with a lower risk of first pulmonary exacerbation. Clinical trial registered with www.clinicaltrials.gov (NCT01859390).

Cost(s) of caring for patients with cystic fibrosis.

PURPOSE OF REVIEW: Cystic fibrosis (CF) has received a lot of attention in the past few years because of increased longevity and the emergence of ground-breaking new drugs targeting the molecular and cellular defects, making a huge clinical difference, and - not incidentally - carrying massive price tags. The prices of these new drugs make the question of overall costs of CF care highly relevant. RECENT FINDINGS: This article reviews recent developments in CF science and treatment, and highlights areas that contribute to costs of CF care, emphasizing how these costs have increased. SUMMARY: This article should help the pediatrician stay abreast of high points of CF care, with an awareness of the factors that wield the biggest influence on overall costs, to patients, families and the US healthcare system.

Effects of a partially supervised conditioning programme in cystic fibrosis: an international multi-centre randomised controlled trial (ACTIVATE-CF): study protocol.

BACKGROUND: Physical activity (PA) and exercise have become an accepted and valued component of cystic fibrosis (CF) care. Regular PA and exercise can positively impact pulmonary function, improve physical fitness, and enhance health-related quality of life (HRQoL). However, motivating people to be more active is challenging. Supervised exercise programs are expensive and labour intensive, and adherence falls off significantly once supervision ends. Unsupervised or partially supervised programs are less costly and more flexible, but compliance can be more problematic. The primary objective of this study is to evaluate the effects of a partially supervised exercise intervention along with regular motivation on forced expiratory volume in 1 s (FEV1) at 6 months in a large international group of CF patients. Secondary endpoints include patient reported HRQoL, as well as levels of anxiety and depression, and control of blood sugar. METHODS/DESIGN: It is planned that a total of 292 patients with CF 12 years and older with a FEV1 ≥ 35% predicted shall be randomised. Following baseline assessments (2 visits) patients are randomised into an intervention and a control group. Thereafter, they will be seen every 3 months for assessments in their centre for one year (4 follow-up visits). Along with individual counselling to increase vigorous PA by at least 3 h per week on each clinic visit, the intervention group documents daily PA and inactivity time and receives a step counter to record their progress within a web-based diary. They also receive monthly phone calls from the study staff during the first 6 months of the study. After 6 months, they continue with the step counter and web-based programme for a further 6 months. The control group receives standard care and keeps their PA level constant during the study period. Thereafter, they receive the intervention as well. DISCUSSION: This is the first large, international multi-centre study to investigate the effects of a PA intervention in CF with motivational feedback on several health outcomes using modern technology. Should this relatively simple programme prove successful, it will be made available on a wider scale internationally. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01744561 ; Registration date: December 6, 2012.

Parent and child perceptions of a self-regulated, home-based exercise program for children with cystic fibrosis.

BACKGROUND: Despite recognized benefits, many children with cystic fibrosis (CF) do not consistently participate in physical activities. There is little empirical literature regarding the feelings and attitudes of children with CF toward exercise programs, parental roles in exercise, or factors influencing exercise experiences during research participation. OBJECTIVES: The aim of this study is to describe the exercise experiences of children with CF and their parents during participation in a 6-month program of self-regulated, home-based exercise. METHODS: This qualitative descriptive study was nested within a randomized controlled trial of a self-regulated, home-based exercise program and used serial semistructured interviews conducted individually at 2 and 6 months with 11 purposively selected children with CF and their parent(s). RESULTS: Six boys and five girls, ages 10-16 years, and parents(nine mothers, four fathers) participated in a total of 44 interviews. Five major thematic categories describing child and parent perceptions and experience of the bicycle exercise program were identified in the transcripts: (a) motivators, (b) barriers, (c) effort/work, (d) exercise routine, and (e) sustaining exercise. Research participation, parent-family participation, health benefits, and the child's personality traits were the primary motivators. Competing activities, priorities, and responsibilities were the major barriers in implementing the exercise program as prescribed. Motivation waned, and the novelty wore off for several (approximately half) parent-child dyads, who planned to decrease or stop the exercise program after the study ended. DISCUSSION: We identified motivators and barriers to a self-regulated, home-based exercise program for children with CF that can be addressed in planning future exercise interventions to maximize the health benefits for children with CF and the feasibility and acceptability to the children and their families.

Cystic fibrosis related diabetes is not associated with maximal aerobic exercise capacity in cystic fibrosis: a cross-sectional analysis of an international multicenter trial.

BACKGROUND: Previous studies have reported differences in aerobic exercise capacity, expressed as peak oxygen uptake (VO2peak), between people with and without cystic fibrosis (CF) related diabetes (CFRD). However, none of the studies controlled for the potential influence of physical activity on VO2peak. We investigated associations between CFRD and VO2peak following rigorous control for confounders including objectively measured physical activity. METHODS: Baseline data from the international multicenter trial ACTIVATE-CF with participants ≥12 years performing up to 4 h per week of vigorous physical activity were used for this project. Multivariable models were computed to study associations between CFRD and VO2peak (mL.min-1) adjusting for a set of pre-defined covariates: age, sex, weight, forced expiratory volume in 1 s (FEV1), breathing reserve index, Pseudomonas aeruginosa infection, and physical activity (aerobic step counts from pedometry). Variables were selected based on their potential confounding effect on the association between VO2peak and CFRD. RESULTS: Among 117 randomized individuals, 103 (52% female) had a maximal exercise test and were included in the analysis. Participants with (n = 19) and without (n = 84) CFRD did not differ in FEV1, physical activity, nutritional status, and other clinical characteristics. There were also no differences in VO2peak (mL.min-1 or mL.kg-1.min-1 or% predicted). In the final multivariable model, all pre-defined covariates were significant predictors of VO2peak (mL.min-1), however CFRD [coefficient 82.1, 95% CI -69.5 to 233.8, p = 0.28] was not. CONCLUSIONS: This study suggests no meaningful differences in VO2peak between people with and without CFRD given comparable levels of physical activity.

Effects of an exercise program in children with cystic fibrosis: are there differences between females and males?

OBJECTIVE: To investigate the adaptive responses of an in-patient exercise program in children with cystic fibrosis (CF) and evaluate the effects of sex. STUDY DESIGN: In total, 158 female and 186 male subjects with CF (age, 12 to 43 years) were studied during a 6-week rehabilitation course. A maximal incremental cycling test was used to determine exercise capacity and responses after 6 weeks of exercise training. Measures included lung function, peak oxygen uptake, peak workload, and peak heart rate. RESULTS: Lung function values were lower in males (P < .05). Females had a lower aerobic capacity (P < .05) at the beginning and at the end of the exercise training program. Similar training effects (P > .05) were seen between sexes in peak oxygen uptake (mL/min, mL/kg/min) and peak heart rate (beats/min) but not in peak workload (Watts, W/kg). CONCLUSIONS: The exercise program improved the fitness level similarly in females and males with CF. Basic physiological sex differences were still seen at the beginning and end of the training, despite the better lung function in females. Moreover, the finding suggested that fitness level and not lung function determined the response to training in CF, with those who were less fit at baseline having the largest response to training.

Prevalence and clinical associations of Staphylococcus aureus small-colony variant respiratory infection in children with cystic fibrosis (SCVSA): a multicentre, observational study.

BACKGROUND: Staphylococcus aureus is the bacterium cultured most often from respiratory secretions of people with cystic fibrosis. Both meticillin-susceptible S aureus and meticillin-resistant S aureus (MRSA) can adapt to form slow-growing, antibiotic-resistant isolates known as small-colony variants that are not routinely identified by clinical laboratories. We aimed to determine the prevalence and clinical significance of S aureus small-colony variants and their subtypes among children with cystic fibrosis. METHODS: The Small Colony Variant Staphylococcus aureus (SCVSA) study was a 2-year longitudinal study of children aged 6-16 years at five US cystic fibrosis centres, using culture methods sensitive for small-colony variants. Children were eligible if they had a documented diagnosis of cystic fibrosis and a minimum of two cystic fibrosis clinic visits and two respiratory cultures in the previous 12 months at enrolment. Participants attended clinic visits quarterly, at which respiratory tract samples were taken and measures of lung function (percentage of predicted forced expiratory volume in 1 s [FEV1] and frequency of respiratory exacerbations) were recorded. We determined the prevalence of small-colony variants and their subtypes, and assessed their independent associations with lung function and respiratory exacerbations using linear mixed-effects and generalised estimating equation logistic regression models. Analyses included both univariate models (unadjusted) and multivariate models that adjusted for potential confounders, including age, sex, race, baseline microbiology, treatment with CFTR modulator, and CTFR genotype. FINDINGS: Between July 1, 2014, and May 26, 2015, we enrolled 230 children. Participants were followed-up for 2 years, with a mean of 6·4 visits (SD 1·14) per participant (range 2-9 visits) and a mean interval between visits of 3·94 months (SD 1·77). Across the 2-year period, S aureus small-colony variants were detected in 64 (28%) participants. Most (103 [56%] of 185) of the small-colony variants detected in these participants were thymidine dependent. Children with small-colony variants had significantly lower mean percentage of predicted FEV1 at baseline than did children without small-colony variants (85·5 [SD 19] vs 92·4 [SD 18·6]; p=0·0145). Small-colony variants were associated with significantly lower percentage of predicted FEV1 throughout the study in regression models, both in univariate analyses (regression coefficient -7·07, 95% CI -12·20 to -1·95; p=0·0068) and in multivariate analyses adjusting for potential confounders (-5·50, -10·51 to -0·48; p=0·0316). Small colony variants of the thymidine-dependent subtype had the strongest association with lung function in multivariate regression models (regression coefficient -10·49, -17·25 to -3·73; p=0·0024). Compared with children without small-colony variants, those with small-colony variants had significantly increased odds of respiratory exacerbations in univariate analyses (odds ratio 1·73, 95% CI 1·19 to 2·52; p=0·0045). Children with thymidine-dependent small-colony variants had significantly increased odds of respiratory exacerbations (2·81, 1·69-4·67; p=0·0001), even after adjusting for age, sex, race, genotype, CFTR modulator, P aeruginosa culture status, and baseline percentage of predicted FEV1 (2·17, 1·33-3·57; p=0·0021), whereas those with non-thymidine-dependent small-colony variants did not. In multivariate models including small-colony variants and MRSA status, P aeruginosa was not independently associated with lung function (regression coefficient -4·77, 95% CI -10·36 to 0·83; p=0·10) and was associated with reduced odds of exacerbations (0·54, 0·36 to 0·81; p=0·0028). Only the small-colony variant form of MRSA was associated with reduced lung function (-8·44, -16·15 to -0·72; p=0·0318) and increased odds of exacerbations (2·15, 1·24 to 3·71; p=0·0061). INTERPRETATION: Infection with small-colony variants, and particularly thymidine-dependent small-colony variants, was common in a multicentre paediatric population with cystic fibrosis and associated with reduced lung function and increased risk of respiratory exacerbations. The adoption of small-colony variant identification and subtyping methods by clinical laboratories, and the inclusion of small-colony variant prevalence data in cystic fibrosis registries, should be considered for ongoing surveillance and study. FUNDING: The Cystic Fibrosis Foundation and the National Institutes of Health.

Sexual and reproductive health care utilization and preferences reported by young women with cystic fibrosis.

BACKGROUND: This study aimed to describe and compare the sexual and reproductive health (SRH) care utilization among young women with cystic fibrosis (CF) with the general United States (U.S.) population. METHODS: Women with CF ages 15-24years from five geographically diverse U.S. CF centers participated in a survey investigating SRH. Results were summarized and compared to a nationally representative sample of young women aged 15-24 who participated in the U.S. National Survey of Family Growth (NSFG) using logistic regression to adjust for confounders. RESULTS: A total of 188 women with CF (19.7±2.7years) completed the survey; data were compared to 1997 NSFG respondents (19.6±0.10years). Women with CF had lower lifetime rates of ever obtaining a Pap smear or pelvic exam (26% vs. 57%; p<0.001) and similar rates of HPV vaccination (44% vs. 43%; p=0.64) compared to NSFG respondents. Thirty-seven percent of women with CF reported seeking contraception and <10% reported contraceptive counseling, STI testing/counseling, or pregnancy testing in their lifetime. In the prior 12months, 41% of NSFG respondents reported seeking contraception, 24% received contraceptive counseling, 22% STI testing/counseling, and 23% pregnancy testing. A minority of women with CF received or discussed SRH care in the CF setting, although 66% wanted to discuss SRH with their CF team. CONCLUSIONS: Young women with CF report low rates of SRH care utilization and desire SRH discussions in the CF setting. Interventions should target improved SRH care delivery and encourage patient-provider communication around SRH in the CF care setting.

Sexual and reproductive health behaviors and experiences reported by young women with cystic fibrosis.

BACKGROUND: The prevalence of general and disease-specific sexual and reproductive health (SRH) concerns is unknown in the United States (U.S.) female CF population. This study aimed to describe and compare the SRH experiences and behaviors of young women with CF with the general U.S. METHODS: Young women with CF ages 15-24years from five geographically diverse U.S. CF centers participated in a survey investigating SRH. Results were summarized and compared to the U.S. National Survey of Family Growth (NSFG) using logistic regression adjusting for confounders. FINDINGS: A total of 188 young women with CF (mean age 19.7±2.7years) completed the survey; data were compared to 1997 NSFG respondents (mean age 19.6±0.10years). Fifty-four percent of women with CF reported having had vaginal sex with a male partner compared to 66% of U.S. women (p=0.55). Women with CF were less likely to have ever used contraception (55% vs. 74%, p=0.0001) or have been tested for sexually transmitted infections in the past year (19% vs. 34%, p=0.001) compared to the general population. Two percent of women with CF reported having ever been pregnant compared to 24% of U.S. women (p<0.0001). One-third of young women with CF reported perceived pubertal delay, 16% urinary incontinence, 16% sexual dysfunction, and 49% yeast infections. INTERPRETATION: Young women with CF face significant SRH concerns and appear to be experiencing gaps in SRH care provision. Opportunities exist for intervention development around this aspect of comprehensive CF care. FUNDING: CF Foundation (KAZMER15A0); U.S. National Institutes of Health (UL1TR000005).

Provider Attitudes and Practices toward Sexual and Reproductive Health Care for Young Women with Cystic Fibrosis.

STUDY OBJECTIVE: To investigate the attitudes and practices of cystic fibrosis (CF) providers toward sexual and reproductive health (SRH) care in young women with CF. DESIGN, SETTING, PARTICIPANTS, AND INTERVENTIONS: Adult and pediatric US CF providers were sent an online survey exploring their attitudes toward SRH importance, SRH care practices, and barriers/facilitators to SRH care in adolescent and/or young adult women. Descriptive statistics and logistic regression were used to analyze results. MAIN OUTCOME MEASURES: Attitudes toward the importance of SRH care in patients with CF and self-report of practice patterns of SRH discussion. RESULTS: Respondents (n = 196) were 57% pediatric (111/196) and 24% adult physicians (48/196) and 19% nurse practitioners (NPs)/physician assistants (PAs) (37/196). Ninety-four percent of respondents believed SRH was important for female patients with CF (184/196). More than 75% believed SRH care should be standardized within the CF care model (147/196) and 41% believed the CF team should have the primary role in SRH discussion and care (80/196). For many CF-specific SRH topics, discrepancies emerged between how important respondents believed these were to address and how often they reported discussing these topics in practice. Significant differences in SRH attitudes and practices were present between adult and pediatric physicians. The most significant barriers to SRH care identified were lack of time (70%, 137/196) and the presence of family in clinic room (54%, 106/196). Potential facilitators included training materials for providers (68%, 133/196) and written (71%, 139/196) or online (76%, 149/196) educational resources for patients. CONCLUSION: CF providers perceive SRH topics as important to discuss, but identify barriers to routine discussion in current practice. Providers endorsed provider training and patient educational resources as means to improve SRH delivery.

Provider and Patient Attitudes Regarding Sexual Health in Young Women With Cystic Fibrosis.

OBJECTIVE: To explore the attitudes, preferences, and experiences of patients with cystic fibrosis (CF) and CF providers toward sexual and reproductive health (SRH) care for young women with CF. METHODS: Young women with CF aged 18 to 30 years from a US CF care center and pediatric and adult CF program directors from a national sample participated in qualitative interviews investigating their experiences regarding SRH care and their attitudes and preferences toward SRH care provision in the CF setting. Interviews were audio-recorded, transcribed, and coded by using a thematic analysis approach. RESULTS: Twenty-two patient participants and 16 CF program directors were interviewed. Themes shared by both groups included the importance of SRH discussion in the CF care setting, patient and provider discomfort as a barrier to SRH care, and the need for SRH educational resources and provider training to improve SRH care. Providers highlighted the lack of standardization around SRH care in the current CF care model. Patients desired SRH educational resources coupled with early SRH discussions initiated by their CF provider. CONCLUSIONS: Both CF providers and patients agree that the CF provider has a fundamental role in providing CF-specific SRH care. Educational resources coupled with individualized SRH discussions may facilitate improved SRH care for young women with CF. Investigation into the implementation of SRH education and services into pediatric-onset chronic disease care models is needed.

Cystic fibrosis program directors' attitudes toward sexual and reproductive health in young women with CF.

INTRODUCTION: Advancements in therapy have led to dramatic increases in the life expectancy of patients with cystic fibrosis (CF). As survival improves, young women with CF will have expectations for their sexual and reproductive health (SRH) futures similar to their counterparts without CF. As they face unique CF-specific SRH concerns, they may rely on CF care providers for disease-specific SRH care provision. The purpose of this study was to investigate the attitudes of CF providers toward female SRH and perceived barriers in the current CF care model. MATERIALS AND METHODS: U.S. CF program directors (n = 16) participated in qualitative interviews investigating attitudes and barriers to female CF SRH care. Interviews were audio-recorded, transcribed, and coded using a thematic analysis approach. RESULTS: Participants (nine pediatric, five adult, and two combined) all agreed CF providers have a fundamental role in CF female SRH care. Most respondents named lack of time and patient and provider discomfort as significant barriers to effective SRH communication. Other reported barriers included: lack of training in SRH, family members in the room, low priority of SRH in setting of other CF issues, and lack of adequate rapport with patients. DISCUSSION: This is the first study to assess the attitudes and experiences of CF care providers toward SRH discussion and care among female CF patients. Despite their perceived fundamental role in CF female SRH care, CF providers face significant barriers. Investment in provider training is needed to better address the complex SRH needs of young female patients.

Strength vs aerobic training in children with cystic fibrosis: a randomized controlled trial.

STUDY OBJECTIVE: Exercise has the potential to improve the ability of a patient with cystic fibrosis (CF) to cope with the physical demands of everyday life, and may improve prognosis. The purpose of this study was to compare the effects of a home-based, semi-supervised, upper-body strength-training regimen with a similarly structured aerobic training regimen. DESIGN: Data were collected during a 1-year randomized clinical trial. SETTING: Counselors conducted in-home visits with the participants once per week for the first 8 weeks followed by monthly visits for the remainder of the study. PATIENTS: Sixty-seven patients with CF, aged 8 to 18 years, participated in the trial. INTERVENTION: Participants in both exercise conditions were encouraged to exercise at least three times per week for 1 year. Each child in the aerobic group was given a stair-stepping machine, and each child in the upper-body strength training group was given an upper-body-only weight-resistance machine. MEASURES AND RESULTS: Aerobic fitness, pulmonary function, quality of life, and strength were measured at baseline, at 6 months, and at 12 months. Strength training increased the maximum weight lifted for biceps curls significantly more than aerobic training (p < 0.02). However, this differential did not remain significant after control for increase in height. Both training procedures were associated with increased strength (p < 0.002) and physical work capacity (PWC) [p < 0.033]. CONCLUSIONS: We concluded that strength and aerobic training may increase upper-body strength, and that both types of training may increase PWC for children with CF. Future trials should be conducted with no-training control subjects and larger samples to increase statistical power.

Measuring ease of breathing in young patients with cystic fibrosis.

Our objective was to compare two new objective measures of ease of breathing with the visual analog scale (VAS). Twenty-eight patients with CF, 7-34 years old (FEV(1) 25-114% of predicted), enrolled. Ease of breathing was evaluated by a standard 10-cm VAS, maximum phonation (time, in seconds, to sustain the syllable "Ahh") using a single breath, and counting in a single breath at one number per second (Count) at rest, following 3 min of stepping exercise at 15 steps per minute (STEP15), and 3 min at 30 steps per minute (STEP30). Heart rate (HR) and oxyhemoglobin saturation (SaO(2)) were measured.HR and VAS increased significantly, and SaO(2), phonation, and Count decreased significantly from rest to STEP15 and STEP30. Phonation time correlated significantly (and inversely) with HR after exercise. Phonation time was positively correlated with SaO(2) at rest and after STEP30. Counts at rest and after STEP30 were significantly related to SaO(2). VAS showed no relationship to heart rate at rest or after exercise, but was related to SaO(2) at the end of STEP30. Test-retest reliability for three trials of phonation was 0.92, and for the five trials of counting was 0.93. Correlation coefficients for maximum phonation at rest, STEP15, and STEP30 on 2 separate days were 0.61, 0.94, and 0.91, respectively. Correlation coefficients for Count at rest, STEP15, and STEP30 on 2 separate days were 0.96, 0.94, and 0.94, respectively. Correlation coefficients for VAS at rest, STEP15, and STEP30 on 2 separate days were 0.25, 0.89, and 0.97, respectively. Thus both the maximum phonation and Count have good test-retest reliability within one session, and across 2 separate days, for both rest and exercise conditions. In conclusion, maximum phonation and Count are valid and reliable measures of ease of breathing; they reflect increasing work loads and show stronger correlations with heart rate and SaO(2) than does VAS. These measures could be an important tool for clinical research and patient care.

Pulmonary problems and management concerns in youth sports.

In the overwhelming majority of exercising youngsters, exercise tolerance is limited by cardiovascular and muscular factors, not the lungs. Even at exhaustion, pulmonary reserve is considerable. Yet some young athletes do experience respiratory problems with exercise. These problems can be assigned to several categories, including those related to underlying acute and chronic respiratory conditions (principally respiratory tract infections, asthma, cystic fibrosis, chest wall deformities, and neuromuscular disorders), and apparent but nonpathological problems (the heavy breathing of anaerobic exercise, relative deconditioning, and anxiety). There are also situations that seem to be problematic but need not be (having the diagnosis of asthma or cystic fibrosis). Pharmacologic management of respiratory problems and perceived problems can be difficult and is discussed with the particular disorder.

How does heart rate recovery after sub-maximal exercise correlate with maximal exercise testing in children with CF?

BACKGROUND: Disease progression in cystic fibrosis (CF) is marked by worsening exercise tolerance. Further, maximal exercise capacity (VO2 peak) correlates with survival in CF, but maximal tests are uncomfortable and resource-intensive. A three-minute step test (STEP) has been validated in CF. Heart rate (HR) recovery after exercise correlates with all-cause mortality in adult non-CF populations. We compared HR recovery after the three-minute step test with VO2 peak in children with CF. METHODS: Twenty-four children with CF performed STEP and a maximal exercise test. Correlation between the tests was assessed. RESULTS: Maximum HR on STEP was lower than on the maximal test (140 vs. 190, p<0.01). Peak HR during STEP correlated inversely with VO2 peak. In subjects with mild lung disease, faster HR recovery after STEP correlated with higher VO2 peak. CONCLUSIONS: The three-minute step test is a feasible submaximal test in this patient population. HR during and after a three-minute step test may reflect VO2 peak in children with CF.

Interval exercise training in cystic fibrosis -- effects on exercise capacity in severely affected adults.

The aims of the present study were to investigate the effects of IT on lung function power (P) and oxygen uptake (VO2) at peak performance (peak) and ventilatory anaerobic threshold (VAT) in CF patients who were unable to participate in a standard exercise program (SEP) and to compare these IT responses with corresponding effects in CF patients performing SEP. 20 patients (FEV1 25.5 ± 7.5%; pred; SpO2 < 90% at rest or P lower than 0.3 W/kg) who were unable to participate in SEP were allocated to IT (5 × 20 min weekly). 23 patients (FEV1 31.6 ± 4.2%; p < 0.05) did 5 × 45 min per week of SEP. Lung function remained unchanged in both groups. VO2peak and PVAT increased in both groups (p < 0.05). However, only after the SEP an increase in Ppeak (p < 0.05) and only after IT a higher VO2VAT (p < 0.05) were found. Compared to SEP, IT improved submaximal exercise capacity to a greater extent whereas responsiveness on peak performance was higher in SEP. This seems to indicate a specific potential of IT for positive peripheral muscular adaptations in spite of diminishing potential of pulmonary improvement. IT represents an alternative, effective and safe training regimen with patients with CF and severe lung disease, with a greater potential than SEP.

Exercise intensity self-regulation using the OMNI scale in children with cystic fibrosis.

Prescribing exercise at intensities that improve fitness is difficult in children with cystic fibrosis (CF) due to ventilatory limitations and fluctuating health status. Our aim was to determine if children with CF could regulate the intensity of cycle ergometer and treadmill exercise using target ratings of perceived exertion (RPE) derived from the Children's OMNI Scale. We examined prescription congruence (similar oxygen consumption [VO2] and heart rate [HR] for target RPE) and intensity discrimination (different VO2 and HR for different RPEs), from cycle to cycle and cycle to treadmill. Subjects were 24 children (12 male, 12 female), aged 10-17 years with varying disease severity. Each child participated in one orientation, one estimation trial (graded maximal exercise test), and two production trials (cycle and treadmill, alternating between RPE 4 and 7). At RPE 4, congruence was evident for both VO2 and HR on the treadmill. On the cycle at RPE 4, VO2 was significantly higher only in the first production trial, although HRs tended to be higher in the production trials than the estimation trial. Prescription congruence was also supported at RPE 7, with no significant differences in VO2 or HR between estimation and production trials on cycle or treadmill. Results fully supported intensity discrimination, with significant differences between VO2 and HR at RPE 4 and 7 (P < 0.0001). Children with CF appear capable of using the OMNI Scale to regulate cycle and treadmill exercise intensity. Training using this methodology has the potential to promote fitness in children with CF of varying severity.