Objectives: This study primarily aimed to investigate the clinical determinants of the Modified Incremental Step Test (MIST) in adults with non-cystic fibrosis bronchiectasis (NCFB). A secondary objective was to compare the cardiopulmonary responses after the MIST and Incremental Shuttle Walk Test (ISWT), two commonly adopted symptom-limited maximum field tests in chronic respiratory diseases. Methods: Forty-six patients with clinically stable bronchiectasis participated in this cross-sectional study. MIST and ISWT were performed to determine exercise capacity, while disease severity, fatigue, and quality of life were assessed using the Bronchiectasis Severity Index (BSI), the Fatigue Severity Scale (FSS), and St. George's Respiratory Questionnaire (SGRQ), respectively. Quadriceps muscle strength was evaluated using a hand-held dynamometer, walking speed with a wireless inertial sensing device, and the level of physical activity (steps/day) with a pedometer. Results: The BSI score, quadriceps muscle strength, daily step count, and the SGRQ total score explained 61.9% of the variance in the MIST (p < 0.001, R2 = 0.67, AR2 = 0.619). The BSI score (r = -0.412, p = 0.004), quadriceps muscle strength (r = 0.574, p = 0.001), daily step count (r = 0.523, p < 0.001), walking speed (r = 0.402, p = 0.006), FSS score (r = -0.551, p < 0.001), and SGRQ total score (r = -0.570, p < 0.001) correlated with the MIST. The patients achieved higher heart rates (HR), HR%, desaturation, dyspnea, and leg fatigue in the MIST compared to the ISWT (p < 0.05). Conclusions: Disease severity, quadriceps muscle strength, physical activity level, and quality of life were determinants of MIST. The advantages of the MIST, including higher cardiopulmonary response than ISWT and greater portability, which facilitates its use in various settings, make MIST the preferred choice for investigating symptom-limited exercise capacity in patients with NCFB.

Keywords: bronchiectasis, exercise capacity, step test, physical activity, walking speed, quality of life.

Objective: To analyze the shuttle walk test, and its respective retest, comparing children with cystic fibrosis (CF) to normal children. Methods: The children were divided into two groups: the CF group, composed of children in whom the diagnosis had been confirmed through sweat testing; and the control group, composed of normal children with no history of pulmonary diseases and no alterations in respiratory function. The children were submitted to at least two consecutive tests, 30 min apart. We evaluated distance walked, cardiac overload, peripheral oxygen saturation (SpO2) and subjective perception of exertion (dyspnea at rest scale and Borg dyspnea scale). Results: A total of 28 children were evaluated. Ages ranged from 7 to 15 years (11.57 ± 2.50 and 11.28 ± 1.85 years for the CF and control groups, respectively). The Borg scale scores were significantly higher in the controls (p = 0.007). No differences were found regarding cardiac overload and SpO2. In relation to the intergroup retest, the controls presented significant improvements on the second test, both in the distance walked and in dyspnea at rest (p = 0.014 and p = 0.036, respectively). The CF group presented a significant improvement only in the dyspnea at rest score (p = 0.168 and p = 0.042, respectively). Conclusion: The cardiac overload imposed by the test did not differ between the groups. The greater fatigue at the beginning of the second test suggests that the 30 min rest between the tests was insufficient.

Keywords: Cystic fibrosis; Exercise test; Heart rate.

Objective: Surgical resection remains the gold standard treatment for bronchiectasis in patients who present with hemoptysis or suppuration, as well as in those who do not respond to clinical treatment. We sought to investigate the efficacy of sublobar resection (segmentectomy) and compare it with that of lobar resection (lobectomy) in patients with non-cystic fibrosis bronchiectasis. Methods: Patients undergoing lobectomy or segmentectomy between 2019 and 2023 were included in the study. We analyzed intraoperative complications and postoperative outcomes, including length of hospital stay, length of ICU stay, and disease recurrence. Results: There was no significant difference between the lobectomy and segmentectomy groups regarding the occurrence of intraoperative complications such as bleeding > 1000 ml, cardiogenic shock, and ventilatory instability (p > 0.999). However, the frequency of complications was significantly lower in the segmentectomy group than in the lobectomy group (p = 0.016). Hospital stays were longer in the lobectomy group than in the segmentectomy group (16 days vs. 5 days; p = 0.027), as were ICU stays (7 days vs. 1 day; p = 0.006). There was no significant difference between the lobectomy and segmentectomy groups regarding the recurrence rate (p = 0.541). Conclusions: Early identification of bronchiectasis patients who are candidates for surgical resection is essential because those who are identified as such early on are candidates for parenchyma-sparing resections, which are similar to lobar resections in terms of disease control and lead to shorter hospital stays and better postoperative outcomes.

Keywords: Bronchiectasis; Thoracic surgery; Disease-free survival.

Objective: To evaluate the responsiveness of the six-minute step test (6MST) to an aerobic physical training program (PTP) and to determine the efficacy of the PTP regarding spirometric variables during the 6MST, as well as physical performance, sensation of dyspnea, and SpO2 during the 6MST and the six-minute walk test (6MWT), in patients with COPD. Methods: This was a controlled, prospective randomized study involving patients clinically diagnosed with COPD, with an FEV1/FVC ratio < 70%, and having been clinically stable in the last two months. The patients were randomized to undergo a PTP on a treadmill, three times a week, for six weeks (PTP group) or not (control group). Histories were taken from all of the patients, who received regular respiratory therapy during the study period, undergoing physical examination and spirometry before and after bronchodilator use; incremental symptom-limited cardiopulmonary exercise testing; the 6MST; and the 6MWT. Results: Of the 36 patients that completed the study, 21 and 15 were in the PTP and control groups, respectively. In the PTP group, there was a significant increase in the number of steps climbed during the 6MST and in the six-minute walk distance (in m and % of predicted), as well as a significant decrease in the sensation of dyspnea during the 6MWT. Conclusions: The 6MST showed responsiveness to the PTP. However, the 6MWT appears to be more responsive to the PTP proposed.

Keywords: Exercise test; Exercise; Pulmonary disease, chronic obstructive.

Objective: One of the common limitations after COVID-19 pneumonia is the decrease in exercise capacity. The identification of the factors affecting exercise capacity and the assessment of patients at risk are important for determining treatment strategy. This study was conducted to determine the predictors of decreased exercise capacity in long post-COVID-19 patients. Methods: We investigated the association of exercise capacity as measured by the incremental shuttle walk test (ISWT) with age, sex, spirometric variables, respiratory and peripheral muscle strength, quality of life, fatigue, hospital anxiety depression scale, chest X-ray involvement, and hospitalization. The patients were divided into three groups: outpatients, inpatients, and ICU patients. Regression analysis was used to determine which parameters were significant predictors of exercise capacity. Results: Of the 181 patients included in the study, 56 (31%) were female. The mean ISWT in percentage of predicted values (ISWT%pred) was 43.20% in the whole sample, whereas that was 52.89%, 43.71%, and 32.21% in the outpatient, inpatient, and ICU patient groups, respectively. Linear regression analysis showed that predictors of decreased ISWT%pred were sex (ß = 8.089; p = 0.002), mMRC scale score (ß = -7.004; p = 0.001), FVC%pred (ß = 0.151; p = 0.003), and handgrip strength (ß = 0.261; p = 0.030). Conclusions: In long post-COVID-19 patients, sex, perception of dyspnea, restrictive pattern in respiratory function, and decrease in peripheral muscle strength are predictors of reduced exercise capacity that persists three months after COVID-19. In this context, we suggest that pulmonary rehabilitation might be an important therapy for patients after COVID-19.

Keywords: COVID-19; Exercise; Muscle strength; Rehabilitation; Walk test.

Objective: To evaluate the construct validity and reproducibility of the six-minute step test (6MST) in individuals with obstructive sleep apnea (OSA) treated with continuous positive airway pressure (CPAP). Methods: We evaluated 48 volunteers diagnosed with OSA and treated with CPAP for at least two months. The volunteers underwent the six-minute walk test (6MWT) and the 6MST, in random order and on different days, with an interval of, at most, seven days between the two tests. Results: A moderate positive correlation was found between the distance walked on the 6MWT and the number of steps climbed on the 6MST (r = 0.520; p < 0.001). There was no significant difference between the two 6MSTs in terms of the number of steps climbed (121.7 ± 27.1 vs. 123.6 ± 26.7). Reproducibility for performance on the 6MST and for cardiovascular variables was considered excellent (intraclass correlation coefficient > 0.8). Regarding cardiovascular responses, the 6MST produced higher values than did the 6MWT for HR at six minutes, percent predicted maximum HR, and leg fatigue at six minutes, as well as for systolic blood pressure at six minutes and at one minute of recovery. Conclusions: The 6MST is valid and reproducible, producing greater cardiovascular stress than does the 6MWT. However, the 6MST is also characterized as a submaximal test for the assessment of exercise tolerance in individuals with OSA treated with CPAP.

Keywords: Sleep apnea, obstructive; Reproducibility of results; Exercise test; Exercise tolerance.

Objective: To characterize a population of patients with bronchiectasis, correlating clinical, radiological, and functional aspects with the severity of dyspnea. Methods: This was a cross-sectional study involving adult patients with HRCT-confirmed bronchiectasis, categorized according to the severity of dyspnea (as being mildly or severely symptomatic, on the basis of the modified Medical Research Council scale). We correlated the severity of dyspnea with clinical parameters, functional parameters (spirometry values, lung volumes, and DLCO), and CT parameters. Results: We evaluated 114 patients, 47 (41%) of whom were men. The median age (interquartile range) was 42 years (30-55 years). The most common form was idiopathic bronchiectasis. Of the 114 patients, 20 (17.5%) were colonized with Pseudomonas aeruginosa and 59 (51.8%) were under continuous treatment with macrolides. When we applied the Exacerbation in the previous year, FEV1, Age, Colonization, Extension, and Dyspnea score, the severity of dyspnea was categorized as moderate in 54 patients (47.4%), whereas it was categorized as mild in 50 (43.9%) when we applied the Bronchiectasis Severity Index. The most common lung function pattern was one of obstruction, seen in 95 patients (83.3%), and air trapping was seen in 77 patients (68.7%). The prevalence of an obstructive pattern on spirometry was higher among the patients with dyspnea that was more severe, and most functional parameters showed reasonable accuracy in discriminating between levels of dyspnea severity. Conclusions: Patients with bronchiectasis and dyspnea that was more severe had greater functional impairment. The measurement of lung volumes complemented the spirometry data. Because bronchiectasis is a complex, heterogeneous condition, a single variable does not seem to be sufficient to provide an overall characterization of the clinical condition.

Keywords: Bronchiectasis; Dyspnea; Respiratory function tests; Multidetector computed tomography; Plethysmography.

Objective: To identify the predictive factors of oxygen desaturation during the six-minute walk test (6MWT) in patients with cystic fibrosis (CF). Methods: Prospective cross-sectional study involving clinically stable patients with CF aged ≥ 10 years. The patients were submitted to nutritional evaluations, oral glucose tolerance tests, pulmonary function tests, chest X-rays and 6MWTs. Results: The study included 88 patients (43 females and 45 males; mean age, 19.9 ± 7.2 years; mean FEV1, 65.4 ± 28.4%). We observed oxygen desaturation in 13 patients (OD+ group) and no oxygen desaturation in 75 (OD− group). In comparison with OD− group patients, OD+ group patients presented higher mean age (p = 0.004), worse clinical score (p < 0.001), worse radiological score (p < 0.001), higher incidence of glucose intolerance (p = 0.004), lower incidence of methicillin-sensitive Staphylococcus aureus infection (p < 0.001), higher incidence of methicillin-resistant S. aureus infection (p = 0.016), higher incidence of Pseudomonas aeruginosa infection (p = 0.008), lower mean resting SpO2 (p < 0.001) and lower mean FEV1 (p < 0.001). In the logistic regression analysis, oxygen desaturation during the 6MWT correlated with resting SpO2 (OR = 0.305, p < 0.001) and FEV1 (OR = 0.882, p = 0.025). The parameters maximizing the predictive value for oxygen desaturation were resting SpO2 < 96% and FEV1 < 40%. In this sample, 15% of the patients with CF aged ≥ 10 years presented oxygen desaturation during the 6MWT. Conclusions: Resting SpO2 < 96% and FEV1 < 40% can predict oxygen desaturation during the 6MWT.

Keywords: Cystic fibrosis; Respiratory function tests; Exercise tolerance.

Objective: To determine the relevance of screening for the F508del mutation of the cystic fibrosis transmembrane conductance regulator gene as a first step in the genetic diagnosis of cystic fibrosis (CF) by associating the genotype with various clinical variables. Methods: We evaluated 180 CF patients regarding the F508del mutation. The clinical data were obtained from the medical records of the patients and from interviews with their parents or legal guardians. Results: Of the 180 patients studied, 65 (36.1%) did not carry the F508del mutation (group 0 [G0]), 67 (37.2%) were F508del heterozygous (G1), and 48 (26.7%) were F508del homozygous (G2). All three groups showed associations with the clinical variables. Homozygosis was associated with younger patients, younger age at CF diagnosis, and younger age at the first isolation of Pseudomonas aeruginosa (PA), as well as with higher prevalence of pancreatic insufficiency (PI) and non-mucoid PA (NMPA) colonization. In comparison with G1+G2 patients, G0 patients were older; first experienced clinical symptoms, digestive disease, and pulmonary disease at an older age; were older at CF diagnosis and at first PA isolation; and had a lower prevalence of PI and meconium ileus, as well as of colonization by NMPA, mucoid PA, and Burkholderia cepacia. In G1 patients, values were intermediate for age at CF diagnosis; age at first PA isolation, first pulmonary symptoms, and first clinical manifestations; MPA colonization; and OR for PI. Conclusions: The identification of F508del in 63.9% of the patients studied showed that this can be a useful tool as a first step in the genetic diagnosis of CF. The F508del genotype was associated with clinical severity of the disease, especially with the variables related to CF onset.

Keywords: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Genotype; Mutation.

Objective: To determine the probability of oxygen desaturation in healthy individuals undergoing the incremental shuttle walk test (ISWT). Methods: We enrolled 83 healthy subjects: 55 males (including 1 smoker) and 28 females. We determined pre-ISWT FEV1, FEV6, HR and SpO2, as well as post-ISWT HR and SpO2. Results: Mean values overall were as follows: age, 35.05 ± 12.53 years; body mass index, 24.30 ± 3.47 kg/m2; resting HR, 75.12 ± 12.48 bpm; resting SpO2, 97.96 ± 1.02%; FEV1, 3.75 ± 0.81 L; FEV6, 4.45 ± 0.87 L; FEV1/FEV6 ratio, 0.83 ± 0.08 (no restriction or obstruction); incremental shuttle walk distance, 958.30 ± 146.32 m; post-ISWT HR, 162.41 ± 18.24 bpm; and post-ISWT SpO2, 96.27 ± 2.21%. In 11 subjects, post-ISWT SpO2 was higher than was pre-ISWT SpO2. In 17 subjects, there was a 4% decrease in SpO2 after the ISWT. There were no statistically significant differences between the groups with and without post-ISWT oxygen desaturation in terms of age, gender, FEV1, FEV6, FEV1/FEV6, pre-ISWT SpO2, incremental shuttle walk distance, HR, or percentage of maximal HR. In the individuals with post-ISWT oxygen desaturation, the body mass index was higher (p = 0.01) and post-ISWT SpO2 was lower (p = 0.0001). Conclusions: Healthy individuals can present oxygen desaturation after the ISWT. Using the ISWT to predict subtle respiratory abnormalities can be misleading. In healthy subjects, oxygen desaturation is common after the ISWT, as it is during any intense physical activity.

Keywords: Heart function tests; Respiratory function tests; Body mass index; Oximetry

INTRODUCTION: Cystic Fibrosis is usually diagnosed in childhood. In Brazil, few studies have approached CF diagnosed in adulthood. OBJECTIVE:The aim of this study was to describe demographic and clinical characteristics and spirometric data of patients with CF diagnosed in adulthood (over 16 years of age) in Bahia, Brazil. METHODS: Twenty-eight patients with cystic fibrosis diagnosed in adulthood were evaluated at the Reference Center of Cystic Fibrosis of the state of Bahia. Variables of interest were age, gender, race, body mass index (BMI), sputum culture, presence of sinusitis and bronchiectasis, spirometric tests with the best values performed for forced expiratory volume in the first second (FEV1), forced vital capacity (FVC) and response to bronchodilators. RESULTS: Mean age of diagnosis was 31.1 ± 12.4 years. Of the patients, 53.4% were black and mulatto and the mean BMI was 18.7 ± 3.0 kg/m2. P aeruginosa was present in 12 (43%) of the total patients. The mean percentages ± SD of FVC and FEV1 were 58.9 ± 21.6% and 44.1 ± 23%, respectively. In the group of patients with presence of P. aeruginosa in sputum cultures, mean of the spirometry parameters were lower than those of the P. aeruginosa-free group. However, this difference achieved a statistically significant difference (p = 0.0007) only in FVC . CONCLUSIONS: In agreement with many authors, this study strengthen the point of view that CF must be investigated in patients with recurrent infections, sinusitis and bronchiectasis even in adulthood. Values of the percentages of FVC and FEV1 in relation to those foreseen were lower in patients bearers of P. aeruginosa thereby showing a higher deterioration of the pulmonary function.

Keywords: Cystic fibrosis/diagnosis. Adult. Spirometry/methods.

Objective: To evaluate physical performance on the six-minute walk test (6MWT) in patients with non-cystic fibrosis bronchiectasis and to investigate its relationship with quality of life (QoL). To identify predictors of exercise performance, we also investigated whether six-minute walk distance (6MWD) is associated with clinical and spirometric findings. Methods: This was a cross-sectional study involving patients with non-cystic fibrosis bronchiectasis (age,  18 years), with at least one respiratory symptom for  2 years and an FEV1  70% of predicted. Patients underwent clinical evaluation, pulmonary function tests, the 6MWT, and QoL assessment with the Medical Outcomes Study 36-item Short-Form Health Survey (SF-36). Results: We included 70 patients (48 females). Mean age was 54.5 ± 17.7 years, and mean FEV1 was 44.9 ± 14.5% of predicted. The patients were divided into two groups: 6MWD-low (6MWD below the predicted lower limit; n = 23); and 6MWD-norm (normal 6MWD; n = 47). The following variables were significantly lower in the 6MWD-low group than in the 6MWD-norm group: age; age at diagnosis of bronchiectasis; proportion of former smokers; body mass index (BMI); FEV1% of predicted; and MEP% of predicted. There were no significant differences in the SF-36 scores between the groups. In the logistic regression model, lower age and lower BMI were significantly associated with lower 6MWD. Conclusions: In this sample, there was a high proportion of patients who had a lower than expected 6MWD. Although 6MWD was not related to QoL, it was associated with age and BMI.

Keywords: Bronchiectasis; Quality of life; Respiratory function tests; Exercise tolerance.

Objective: To determine reference values for incremental shuttle walk distance (ISWD) and peak physiological responses during the incremental shuttle walk test (ISWT), as well as to develop a series of predictive equations for those variables in healthy adults. Methods: We evaluated 103 healthy participants ≥ 40 years of age (54 women and 49 men). We fitted each participant with a gas analysis system for use during the ISWT. Oxygen consumption (VO2), carbon dioxide production, minute ventilation, heart rate (HR), ISWD, and maximal walking velocity (MWV) were obtained as primary outcomes. We also assessed hand grip strength (HGS) and lean body mass (LBM). Results: The regression analysis models, including physiological variables, ISWD, and MWV (adjusted for age, body mass, height, and sex), produced R2 values ranging from 0.40 to 0.65 (for HR and peak VO2, respectively). Using the models including LBM or HGS, we obtained no significant increase in the R2 values for predicting peak VO2, although the use of those models did result in slight increases in the R2 values for ISWD and MWV (of 8% and 12%, respectively). The variables ISWD, MWV, and ISWD Î body mass, respectively, explained 76.7%, 73.3%, and 81.2% of peak VO2 variability. Conclusions:áOur results provide reference values for ISWD and physiological responses to the ISWT, which can be properly estimated by determining simple demographic and anthropometric characteristics in healthy adults ≥ 40 years of age. The ISWT could be used in assessing physical fitness in the general adult population and in designing individualized walking programs.

Keywords: Reference values; Pulmonary gas exchange; Walking; Exercise test.

Objective: To evaluate spirometric patterns of respiratory disorders and their relationship with functional severity and maximal expiratory flows at low lung volumes in patients with cystic fibrosis (CF). Methods: A retrospective cross-sectional study including adolescents and adults with CF. All of the patients were submitted to spirometry. Patients were classified as having preserved respiratory function, obstructive lung disease (OLD), OLD with reduced FVC, presumptive restrictive lung disease (RLD) or mixed obstructive and restrictive lung disease (MORLD). Maximal expiratory flows at low lung volumes were assessed using FEF25-75%, FEF75% and FEF75%/FVC. We included 65 normal subjects, also submitted to spirometry, as a control group. Results: The study group included 65 patients: 8 (12.3%) with preserved lung function; 18 (27.7%) with OLD; 24 (36.9%) with OLD and reduced FVC; 5 (7.7%) with presumptive RLD; and 10 (15.4%) with MORLD. The FEV1 was significantly lower in the OLD with reduced FVC group and the MORLD group than in the other groups (p < 0.001). In the patients with preserved respiratory function, FEF25-75% and FEF75% were significantly reduced in 1 patient, as was FEF75%/FVC in 2 patients. Conclusions: The respiratory pattern was impaired in 88% of the patients with CF. The most common pattern was OLD with reduced FVC. The degree of functional impairment was greater in the OLD with reduced FVC group and in the MORLD group than in the other groups. Maximal expiratory flows at low lung volumes were impaired in a low percentage of patients with preserved respiratory function.

Keywords: Cystic fibrosis; Respiratory function tests; Spirometry; Maximal expiratory flow-volume curves.

Objective: To identify microorganisms in sputum samples of patients with stable non-cystic fibrosis bronchiectasis and to determine risk factors related to the isolation of Pseudomonas aeruginosa (PA) in those patients. Methods: Consecutive patients were recruited from a tertiary hospital outpatient clinic in the city of Fortaleza, Brazil. The patients were submitted to spirometry, six-minute walk test, HRCT, and sputum collection. Data on serum fibrinogen levels, disease severity, sputum color, and history of azithromycin treatment were collected. Results: The study included 112 patients, and females predominated (68%). The mean age was 51.6 ± 17.4 years. Most patients presented with mild-to-moderate disease (83%). The mean six-minute walk distance was 468.8 ± 87.9 m. Mean FEV1 and FVC, in % of predicted values, were 60.4 ± 21.8% and 69.9 ± 18.5%, respectively. The mean serum fibrinogen level was 396.1 ± 76.3 mg/dL. PA was isolated in 47 patients, other potentially pathogenic microorganisms (PPMs) were isolated in 31 patients, and non-PPMs were isolated in 34 patients. Purulent sputum was identified in 77 patients (68%). The patients with PA, when compared with those without it, presented with more severe disease, higher serum fibrinogen levels, and lower FVC%. In addition, purulent sputum and long-term azithromycin treatment were more common in those with PA. The multivariate regression analysis showed that the independent factors associated with PA were serum fibrinogen level > 400 mg/dL (OR = 3.0; 95% CI: 1.1-7.7) and purulent sputum (OR = 4.3; 95% CI: 1.6-11.3). Conclusions: In our sample, the prevalence of PA in sputum was 42%. Sputum color and inflammatory markers were able to predict the isolation of PA, emphasizing the importance of routine sputum monitoring.

Keywords: Bronchiectasis; Pseudomonas aeruginosa; Sputum/microbiology.

Objective: To compare patients with cystic fibrosis and healthy individuals in terms of their functional performance on the six-minute walk test (6MWT). Methods: A prospective, cross-sectional study involving healthy individuals and patients with cystic fibrosis treated at a referral university hospital in the city of Campinas, Brazil. The 6MWT was administered in accordance with the American Thoracic Society guidelines, and it was repeated after a 30-min rest period. For all of the participants, RR, HR, SpO2, and Borg scale scores were obtained. For the cystic fibrosis patients, nutritional status and spirometric values were determined. Patients with pulmonary exacerbation were excluded. Spearman's correlation coefficient and repeated measures ANOVA were used. Results: The cystic fibrosis group comprised 55 patients, and the control group comprised 185 healthy individuals. The mean ages were 12.2 ± 4.3 and 11.3 ± 4.3 years, respectively. The six-minute walk distance (6MWD) was significantly shorter in the cystic fibrosis group than in the control group for both tests (547.2 ± 80.6 m vs. 610.3 ± 53.4 m for the first and 552.2 ± 82.1 m vs. 616.2 ± 58.0 m for the second; p < 0.0001 for both). The 6MWD correlated with age, weight, and height only in the cystic fibrosis group. During the tests, SpO2 remained stable, whereas HR and RR increased. Conclusions: In our sample, functional performance on the 6MWT was poorer among the cystic fibrosis patients than among the healthy controls in the same age bracket, and we found immediate repetition of the test to be unadvisable.

Keywords: Cystic fibrosis; Exercise tolerance; Dyspnea.