Eucapnic Voluntary Hyperpnea Challenge Research Articles

Do Patients With Physician Diagnosis Of Exercise-induced Bronchoconstriction Provide A Positive Eucapnic Voluntary Hyperpnoea Challenge?

Do Patients With Physician Diagnosis Of Exercise-induced Bronchoconstriction Provide A Positive Eucapnic Voluntary Hyperpnoea Challenge?

Ventilation Rates Achieved in Eucapnic Voluntary Hyperpnea Challenge and Exercise-Induced Bronchoconstriction Diagnosis in Young Patients with Asthma.

Exercise-induced bronchoconstriction (EIB) affects approximately 50% of young asthma patients, impairing their participation in sports and physical activities. Eucapnic voluntary hyperpnea (EVH) is an approved surrogate challenge to exercise for objective EIB diagnosis, but the required minimum target hyperventilation rates remain unexplored in this population. This study aimed to evaluate the association between the achieved ventilation rates (VRs) during a challenge and EIB-compatible response (EIB-cr) in young asthma patients. This cross-sectional study included 72 asthma patients aged 10-20years. Forced expiratory volume in the first second (FEV1) was measured before and 5, 15, and 30min after the EVH. The target VR was set at 21 times the individual's baseline FEV1. A decrease of > 10% in FEV1 after the challenge was considered an EIB-cr. The challenge was repeated after 48-72h in those without an EIB-cr. Thirty-six individuals had an EIB-cr at initial evaluation. The median VRs achieved was not different between individuals with and without an EIB-cr (19.8 versus 17.9; p = 0.619). The proportion of individuals with an EIB-cr was nor different comparing those who achieved (12/25) or not (24/47) the calculated target VRs (p = 0.804). At the repeated EVH challenge an EIB-cr was observed in 14/36 individuals with a negative response in the first evaluation, with no differences in achieved VRs between the two tests (p = 0.463). Irrespective of the achieved VR, an EIB-compatible response after an EVH challenge must be considered relevant for clinical and therapeutic judgment and negative tests should be repeated.

Serum and sputum MMP-9/TIMP-1 in winter sports athletes and swimmers: relationships with airway function

Introduction Skiers and swimmers present characteristics of airway inflammation and remodelling of the extracellular matrix similar to what is observed in mild asthma. We aimed to compare serum and sputum MMP-9/TIMP-1 levels, to assess the balance between airway fibrogenesis and inflammation process in both categories of athletes, and to observe its seasonal variations in winter sports athletes. Methods We conducted a retrospective study. Winter sports athletes (n = 41), swimmers (n = 25) and healthy nonathletes (n = 10) had blood sampling, lung function measurement, skin prick tests, eucapnic voluntary hyperpnoea challenge, methacholine inhalation test, and induced sputum analysis. Twelve winter sport athletes performed the tests during both summer and winter. Serum and sputum biomarkers were measured by ELISA. Results No significant difference in serum or sputum MMP-9/TIMP-1 ratio was observed between groups, nor relationship with airway function or responsiveness. Serum MMP-9/TIMP-1 ratio was higher during the summer in winter sport athletes compared with winter season (median [Interquartile range]: 3.65 [2.47-4.03] ng.ml−1 and 1.27 [0.97-1.62] ng.ml−1, respectively, p = 0.005). Sputum MMP-9 correlated with methacholine PC20 (r = 0.45, p = 0.019) and serum cc16/SP-D ratio (r = −0.47, p = 0.013). Conclusion MMP-9/TIMP-1 ratio in sputum or serum may fluctuate with training or environment but does not correlate with airway function or responsiveness in athletes.

Eucapnic voluntary hyperpnea challenge can support management of exercise‐induced bronchoconstriction in elite swimmers

Introduction: This study investigated the use of eucapnic voluntary hyperpnea (EVH) to monitor efficacy of pharmacological therapy in elite swimmers with exercise-induced bronchoconstriction (EIB). Secondly, it evaluated the long-term test-retest repeatability of EVH in this population. Methods: Twenty-seven elite international swimmers were included in this retrospective analysis of comprehensive respiratory assessments. Following an initial “withheld-therapy” assessment, athletes with EIB had been prescribed appropriate pharmacological therapy and returned twelve months later for a follow-up assessment to monitor EIB protection afforded by treatment. EIB-negative athletes had returned to confirm initial diagnosis, as were still reporting persistent respiratory symptoms. Athletes were retrospectively grouped into either “Therapy Adherent Group” (n = 12) or “Repeatability Group” (discontinued therapy at follow-up or EIB-negative, n = 15). Results: Greatest fall in forced expiratory volume in 1 second (ΔFEV1max) was significantly lower following therapy adherence (−11.8 ± 3.8%) compared to initial assessment (−24.0 ± 11.3%; P < .01). “Repeatability Group” ΔFEV1max did not differ significantly between initial assessment (−13.1 ± 4.5%) and follow-up (−12.3 ± 5.6%; P = .32), and showed good agreement (0.6%; −5.9%, 7.1%). Conclusion: A follow-up assessment utilizing EVH is useful in the management of EIB and shows good test-retest repeatability over twelve months in elite swimmers who discontinue treatment or are EIB-negative.

Spirometric Response to Bronchodilator and Eucapnic Voluntary Hyperpnea in Adults With Asthma.

The spirometric response to fast-acting bronchodilator is used clinically to diagnose asthma and in clinical research to verify its presence. However, bronchodilator responsiveness does not correlate with airway hyper-responsiveness measured with the direct-acting stimulus of methacholine, demonstrating that bronchodilator responsiveness is a problematic method for diagnosing asthma. The relationship between bronchodilator responsiveness and airway hyper-responsiveness assessed with indirect-acting stimuli is not known. Retrospectively, the spirometric responses to inhaled bronchodilator and a eucapnic voluntary hyperpnea challenge (EVH) were compared in 39 non-smoking adult subjects with asthma (26 male, 13 female; mean ± SD age 26.9 ± 7.8 y; mean ± SD body mass index 26.3 ± 4.7 kg/m2). All subjects met one or both of 2 criteria: ≥ 12% and 200 mL increase in FEV1 after inhaled bronchodilator, and ≥ 10% decrease in FEV1 after an EVH challenge. Overall, FEV1 increased by 9.9 ± 7.9% after bronchodilator (3.93 ± 0.97 to 4.28 ± 0.91 L, P < .001) and decreased by 23.9 ± 15.0% after the EVH challenge (3.89 ± 0.89 to 2.96 ± 0.88 L, P < .001). However, the change in FEV1 after bronchodilator did not correlate with the change after EVH challenge (r = 0.062, P = .71). Significant bronchodilator responsiveness predicted a positive response to EVH challenge in 9 of 33 subjects (sensitivity 27%). Following EVH, the change in FEV1 strongly correlated with the change in FVC (FEV1 percent change vs FVC percent change, r = 0.831, P < .001; FEV1 ΔL vs FVC ΔL, r = 0.799, P < .001). These results extend previous findings that demonstrate a lack of association between bronchodilator responsiveness and methacholine responsiveness. Given the poor concordance between the spirometric response to fast-acting bronchodilator and the EVH challenge, these findings suggest that the airway response to inhaled β2-agonist must be interpreted with caution and in the context of its determinants and limitations.

Abstracts PDS

Background: Exercise-induced bronchoconstriction (EIB) is a common cause of breathing difficulty in athletes. Fractional exhaled nitric oxide (FeNO) is an indirect marker of airway inflammation, recommended for the assessment and management of asthma; however, the role of FeNO in detecting and monitoring EIB has yet to be fully established. The aim of this study was therefore to evaluate the predictive value of FeNO to confirm or refute EIB in athletes presenting with exertional dyspnoea. Method: Seventy athletes (male: n = 45) (age: 35 ± 11 years) reporting respiratory symptoms (i.e. wheeze, cough and dyspnoea) during exercise attended the laboratory on a single occasion. All athletes performed resting FeNO and spirometry pre-and-post a eucapnic voluntary hyperpnoea challenge (EVH) in accordance with international guidelines. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for established FeNO thresholds: (intermediate [≥25ppb] and high [>50ppb]) and evaluated against objective evidence of EIB: (EVH diagnostic cut-off [-10% ΔFEV1 at two consecutive time-points] and [-15% ΔFEV1 at one time-point]). The diagnostic accuracy of FeNO was calculated using receiver operating characteristics area under the curve (ROC-AUC). Results: All had normal resting lung function (>80% FEV1 pred). The prevalence of EIB was 33% (-10% ΔFEV1) and 23% (-15% ΔFEV1) (median (IQR) ΔFEV1 = -7% (10.02)). FeNO values ≥25ppb and >50ppb were observed in 49% and 23% of the cohort, respectively. ROC-AUC for FeNO was 75% (-10% ΔFEV1) and 86% (-15% ΔFEV1). Sensitivity, specificity, PPV and NPV are presented in Table 1. Conclusion: Our findings indicate that FeNO >50ppb provides good specificity for a positive EVH test; however, should not replace indirect bronchoprovocation for diagnostic purposes. The high proportion of athletes reporting breathing difficulty in the absence of EIB highlights the requirement to consider alternative causes of exertional dyspnoea during clinical work-up.

The effect of diurnal variation in exercise-induced bronchoconstriction

Objective: Exercise-induced bronchoconstriction (EIB) is an acute, transient narrowing of the airway as a result of exercise. Diurnal variation in asthma is well-established, however, few studies have investigated diurnal variability in EIB; no study has used eucapnic voluntary hyperpnea (EVH). The aim of this study was to examine circadian variability in EIB using EVH.Methods: Fourteen recreationally-active males with mild to moderate asthma and nine healthy controls were randomized to first complete either an AM (07:00–08:00) or PM (17:00–18:00) EVH challenge, followed by the alternate test 34 h to 7 days later. The EVH protocol comprised of six-minutes of hyperventilation of a 5% CO2 gas at a minimum ventilation rate of 21 × FEV1 min−1. The primary outcome measure was FEV1 pre- and post-EVH.Results: We observed no diurnal effect on EIB in the asthma group. The minimum observed post-EVH FEV1 in the asthma cohort was 3.58 ± 0.95 L in AM and 3.62 ± 0.87 L in PM tests, corresponding to a 15.0 ± 15.3% vs. 14.9 ± 14.7% reduction from baseline, respectively. The asthma group showed similar baseline FEV1 before AM (4.21 ± 0.79 L) and PM (4.25 ± 0.65 L) tests. No difference was observed in minute ventilation between AM (26.1 ± 3.4 × FEV1 min−1) and PM (25.6 ± 3.8 × FEV1 min−1) tests for the asthma cohort. Controls displayed no significant changes in FEV1 or minute ventilation between tests.Conclusions: When baseline pulmonary function is similar, this study suggests that time-of-day has no effect on EIB in mild to moderate asthma.

Compact Eucapnic Voluntary Hyperpnoea Apparatus for Exercise-Induced Respiratory Disease Detection

Eucapnic voluntary hyperpnoea (EVH) challenge provides objective criteria for exercise-induced asthma (EIA) or exercise-induced bronchoconstriction (EIB), and it was recommended to justify the use of inhaled β2-agonists by athletes for the Olympics. This paper presents the development of a compact and easy-to-use EVH apparatus for assessing EIB in human subjects. The compact apparatus has been validated on human subjects and the results have been compared to the conventional EVH system. Twenty-two swimmers, including eleven healthy subjects and eleven subjects who had been physician-diagnosed with asthma, were recruited from sport and recreation centers throughout Auckland, New Zealand. Each subject performed two EVH challenge tests using the proposed breathing apparatus and the conventional Phillips EVH apparatus on separate days, respectively. Forced expiratory volume in one second (FEV1) was measured before and after the challenges. A reduction in FEV1 of 10% or more was considered positive. Of the eleven subjects who were previously diagnosed with asthma, EIB was present in all subjects (100%) in the compact EVH group, while it was presented in ten subjects (90.91%) in the conventional EVH challenge group. Of the eleven healthy subjects, EIB was present in one subject (4.55%) in the compact EVH group, while it was not present in the conventional EVH group. Experimental results showed that the compact EVH system has potential to become an alternative tool for EIB detection.

Diagnosing Exercise Induced Bronchoconstriction

Eucapnic Voluntary Hyperpnoea (EVH) is a sensitive indirect airway challenge to assist in the diagnosis of Exercise Induced Bronchoconstriction (EIB). However, it has been previously reported that a positive EVH challenge may not necessarily predictive a positive exercise challenge (EX). EX have previously shown varying sensitivity due to differences in control over the inspired air water content, with studies being conducted in ambient lab conditions or using medical grade dry air. PURPOSE: To compare the EVH challenge with an EX in a controlled dry air environment, to see if a standardised EX can be used in the diagnosis or EIB. METHODS: Thirty-one healthy participants (10 female; 21 males, age 36 ± 10 yrs, exercising 7.7 ± 3.0 hrs per week) gave informed consent. Eight had a history of asthma but were not taking preventative medication. Participants completed an EVH and an EX on a cycle ergometer in a randomised order. The EVH required participants to breathe a gas mixture (5% CO2, 21% O2 and 74% N2, <2%RH) at a rate equivalent to 85% predicted MVV. The EX was conducted in an environmental chamber (16°c, 25%RH). Following a 4-min set warm up participants completed 6-mins of cycling at a work rate associated with 85% HRmax. Tests were deemed positive if there was a fall in FEV1 of ≥ 10% following the challenge. Results were analysed using paired t-tests and Pearson’s correlation and are presented as mean ± SD. RESULTS: Seven participants were positive to EVH. Of these, only two had a positive response to Ex. No differences in baseline FEV1 between EVH and EX were found (EVH:4.06 ± 0.79, EX: 4.06 ± 0.77 L, p = 0.746). There was a strong correlation between the % fall in FEV1 post EVH and EX (r = 0.520, p = 0.003). However, the % fall in FEV1 post EVH was significantly greater that post EX (EVH: -7.5 ± 5.4, EX: -2.0 ± 3.8 %, p < 0.001). The total amount of air expired was significantly higher in 6 mins EVH compared to 6 mins EX (EVH: 686.5 ± 141.7, EX: 617.9 ± 83.1 L, p = 0.002). CONCLUSION: A positive EVH challenge may not be predictive of a positive Exercise Challenge in a dry environment. EVH may have a greater sensitivity due to the lower water content of inspired air and a greater VE. This suggests that a mild positive EVH challenge (a fall in FEV1 of 10-15%), may not be predictive of EIB.

The acute response to interval and continuous exercise in adults with confirmed airway hyper-responsiveness.

To determine changes in lung function following an acute bout of high intensity interval exercise (HIIE), moderate intensity interval exercise (MIIE), and moderate intensity continuous exercise (MICE) in adults with airway hyper-responsiveness (AHR). A randomized cross-over design was used. Participants completed five laboratory sessions: (1) eucapnic voluntary hyperpnea challenge (2) maximal exercise test to determine peak power output (PPO) and, (3-5) HIIE (90% PPO for 1min followed by 10% PPO for 1min, repeated 10 times), MIIE (65% PPO for 1min followed by 10% PPO for 1min, repeated 10 times) and MICE (65% PPO for 20min). Lung function was assessed pre and post-exercise. Thirteen participants (age: 21.1±2.7years) with mild/moderate asthma completed all protocols. Lung function was significantly lower following the MICE (-14.8%±12.2) protocol compared to the HIIE (-7.1%±8.3) and MIIE (-4.5%±3.3). It appears that MICE is associated with the greatest decline in post-exercise FEV1 among those with AHR. Interval exercise may be better tolerated than continuous exercise among those with AHR.

Computer-Controlled Eucapnic Voluntary Hyperpnea Challenge Method

Eucapnic voluntary hyperpnea (EVH) challenge is a well-established and sensitive method of determining the degree of bronchoconstriction at hospitals and clinics. This paper presents the development of a computer-controlled system for assessing exercise-induced bronchoconstriction (EIB) in humans including a computer graphic user interface (GUI) to control a low-pressure demand valve for better efficiency. GUI is designed to monitor the severity of acute lung airway narrowing using a matlab software and to present the measurement data into a simple user-friendly program consisting of patient information, EVH test analysis, and detection of exercise-induced asthma (EIA) and EIB. The proposed system is assessed using human subjects. Typical outputs from this system showed that for a female participant, a 20.25% and a 15.61% decrease from baseline in her forced expiratory volume in 1 s (FEVl) after 10 and 15 min of the challenge commencement, respectively. Her actual expiratory flow rate (45.833 L/m) and actual total volume of gas respired (275 L) were smaller than the target values. This system widens the usage of EVH challenge in medical areas, and the GUI may serve as a new clinical computer-aided diagnostic tool to help healthcare professionals noninvasively monitor the severity of asthma, EIA, and EIB.

Urinary excretion of lipid mediators in response to repeated eucapnic voluntary hyperpnea in asthmatic subjects.

Exercise-induced bronchoconstriction displays refractoriness manifested as a decreased response to repeated exercise challenge within hours. The refractoriness may be attenuated by inhibition of the biosynthesis of prostaglandins (PG). The aim of the study was to determine which PGs and other lipid mediators are excreted during the refractory period. First, 16 subjects with mild stable asthma performed two repeated 4-min challenges with eucapnic voluntary hyperpnea (EVH) 1 and 3 h apart. There was a similar degree of refractoriness in both protocols (∼15% protection). The 1-h interval was too short to study mediator excretion because the urinary levels did not return to baseline before the second challenge. With the 3-h protocol, there was increased urinary excretion of cysteinyl-leukotrienes and metabolites of the mast cell product PGD2 after both challenges. Next, another eight subjects performed two 6-min challenges with EVH 3 h apart, which produced a greater bronchoconstrictor response than the 4-min protocol (30.0 ± 5.4 vs. 17.7 ± 1.5%; P = 0.0029) and a greater degree of refractoriness (∼30%). Analysis by ultra-performance liquid chromatography triple quadrupole mass spectrometry confirmed excretion of the bronchoconstrictor cysteinyl-leukotrienes and PGD2 during both challenges. In addition, there was increased excretion of the bronchoprotective PGE2, and also of the main metabolite of PGI2. This is the first report of excretion of PGE2 and PGI2 during the refractory period to EVH challenge, suggesting that they may mediate the refractoriness. Maintained excretion of PGD2 and leukotriene E4 following the repeat challenge argues against mast cell mediator depletion as the mechanism of refractoriness.

Diagnosing Exercise-Induced Bronchoconstriction With Eucapnic Voluntary Hyperpnea: Is One Test Enough?

In athletic individuals, a secure diagnosis of exercise-induced bronchoconstriction (EIB) is dependent on objective testing. Indirect bronchoprovocation testing is often used in this context and eucapnic voluntary hyperpnea (EVH) testing is recommended for this purpose, yet the short-term reproducibility of EVH is yet to be appropriately established. The aim of this study was to evaluate the reproducibility of EVH in a cohort of recreational athletes. A cohort of recreational athletes (n= 32) attended the laboratory on two occasions to complete an EVH challenge, separated by a period of 14 or 21 days. Spirometry and impulse oscillometry was performed before and after EVH. Training load was maintained between visits. Prechallenge lung function was similar at both visits (P > .05). No significant difference was observed in maximum change in FEV1 (ΔFEV1max) after EVH between visits (P > .05), and test-retest ΔFEV1max was correlated (intraclass correlation coefficient= 0.81; r(2)= 0.66; P= .001). Poor diagnostic reliability was observed between tests; 11 athletes were diagnosed with EIB (on the basis of ΔFEV1max ≥10%) at visit 1 and at visit 2. However, only 7 athletes were positive at both visits. Although there was a small mean difference in ΔFEV1max between tests (-0.6%), there were wide limits of agreement (-10.7% to 9.5%). Likewise, similar results were observed for impulse oscillometry between visits. In a cohort of recreational athletes, EVH demonstrated poor clinical reproducibility for the diagnosis of EIB. These findings highlight a need for caution when confirming or refuting EIB on the basis of a single indirect bronchoprovocation challenge. When encountering patients with mild or borderline EIB, we recommend that more than one EVH test is performed to exclude or confirm a diagnosis.

Effects of altered airway function on exercise ventilation in asthmatic adults.

Variable airway function is a central feature of the asthmatic condition. Thus, habitually active asthmatics are certain to exercise under conditions of variable airway (dys)function. The purpose of this study was to determine the effects of variable preexercise airway function on ventilation during whole-body exercise in asthmatic adults. Eight mild asthmatic (age = 26 yr; V˙O2peak = 49 mL·kg·min) and nine nonasthmatic (age = 30 yr; V˙O2peak = 46 mL·kg·min) adults performed constant workrate cycling exercise to exhaustion after four separate interventions: 1) a control trial (CON); 2) inhalation of fast-acting β2-agonist (BD); 3) eucapnic voluntary hyperpnea challenge (BC); and 4) sham to the hyperpnea (SHAM). Pulmonary function was assessed at baseline and after each intervention. Exercise ventilation and operating lung volumes were compared among the four exercise trials in both control and asthmatic subjects. Baseline pulmonary function was significantly lower in asthmatic subjects compared with control subjects. In asthmatic subjects, postintervention (i.e., preexercise) forced expiratory volume 1.0 s was significantly different among the four exercise trials (CON = 3.5 ± 0.4, BD = 4.1 ± 0.4, SHAM = 3.6 ± 0.3, BC = 2.8 ± 0.3 L, P < 0.05), whereas it was not different in control subjects. There were no differences in exercise ventilation or operating lung volumes during exercise among the four trials either within asthmatic subjects or between control and asthmatic subjects. These findings suggest that the state of airway function-whether bronchodilated or bronchoconstricted-before exercise in the mild asthmatic does not affect the exercise ventilatory response. Thus, ventilatory system function in the asthmatic appears to be responsive to the acute requirement for increased airflow during whole-body exercise.

Prevalence of bronchoconstriction induced by eucapnic voluntary hyperpnoea in recreationally active individuals

Objective: Exercise-induced bronchoconstriction (EIB) is more prevalent in elite athletes than in the general population. Many of these athletes provide a positive eucapnic voluntary hyperpnoea (EVH) challenge without previous diagnosis of EIB. It is unknown whether this is specific to elite athletes or whether the same risk applies to recreationally active individuals. The purpose of this study was to investigate the prevalence of a positive EVH challenge in a population of recreationally active individuals. Methods: 136 recreationally active individuals (Age: 21.9 ± 3.7 years; Height: 175 ± 9 cm; Weight: 70.9 ± 10.0 kg) without previous history of asthma or EIB, volunteered to take part in the study. All participants completed an EVH challenge, which was deemed positive if FEV1 fell ≥10% from baseline at two consecutive time points, and was reversible following inhalation of a short acting β2-agonist. Results: 18 of 136 (13.2%) participants had a positive EVH challenge. Of the 18 individuals, the fall in FEV1 from baseline ranged from −12% to −50%. At baseline, percentage predicted FEV1 (97.5 ± 12.5% versus 104.9 ± 10%; p < 0.01), FEV1/FVC ratio (79.5 ± 6.9% versus 87.8 ± 5.5%; p < 0.01), FEF25-75 (3.73 ± 1.00 versus 4.73 ± 1.00 l/s; p < 0.01) and predicted PEF (89.4 ± 8.8% versus 97.5 ± 13.6%; p < 0.05) values for EVH positive participants were significantly lower than EVH negative participants respectively. Conclusions: Overall, 13.2% of recreationally active individuals with no previous history of asthma presented with a positive EVH challenge. Individuals who are recreationally active may benefit from an objective bronchial provocation challenge, given that self-reported symptoms alone only provide a supportive role towards a valid EIB diagnosis.

Broncoespasmo induzido por exercício em corredores brasileiros de longa distância de elite

To determine the prevalence of exercise-induced bronchoconstriction among elite long-distance runners in Brazil and whether there is a difference in the training loads among athletes with and without exercise-induced bronchoconstriction. This was a cross-sectional study involving elite long-distance runners with neither current asthma symptoms nor a diagnosis of exercise-induced bronchoconstriction. All of the participants underwent eucapnic voluntary hyperpnea challenge and maximal cardiopulmonary exercise tests, as well as completing questionnaires regarding asthma symptoms and physical activity, in order to monitor their weekly training load. Among the 86 male athletes recruited, participation in the study was agreed to by 20, of whom 5 (25%) were subsequently diagnosed with exercise-induced bronchoconstriction. There were no differences between the athletes with and without exercise-induced bronchoconstriction regarding anthropometric characteristics, peak oxygen consumption, baseline pulmonary function values, or reported asthma symptoms. The weekly training load was significantly lower among those with exercise-induced bronchoconstriction than among those without. In this sample of long-distance runners in Brazil, the prevalence of exercise-induced bronchoconstriction was high.

Airway remodeling and inflammation in competitive swimmers training in indoor chlorinated swimming pools

Airway disorders are common in regular chlorinated swimming pool attendees, particularly competitive athletes, but the impact of intense swimming training on airway function and structure remains unclear. This study aimed to evaluate airway inflammation and remodeling in elite swimmers. Twenty-three elite swimmers were tested during off-training season. All had exhaled nitric oxide measurement, methacholine test, eucapnic voluntary hyperpnea challenge, allergy skin prick tests, and bronchoscopy with bronchial biopsies. Clinical data and tissues from 10 age-matched mild-asthmatic and 10 healthy nonallergic subjects were used for comparison. Swimmers had increased airway mucosa eosinophil and mast cell counts than did controls (P< .05). They had more goblet cell hyperplasia and higher mucin expression than did healthy or asthmatic subjects (P< .05). Agreater submucosal type I and III collagen expression and tenascin deposition was also observed in swimmers than in controls (P< .05). Neither exhaled nitric oxide nor airway responsiveness to methacholine or eucapnic voluntary hyperpnea challenge correlated with these inflammatory and remodeling changes. Intense, long-term swimming training in indoor chlorinated swimming pools is associated with airway changes similar to those seen in mild asthma, but with higher mucin expression. These changes were independent from airway hyperresponsiveness. The long-term physiological and clinical consequences of these changes remain to be clarified.

How to Diagnose Exercise Induced Asthma?

Exercise induced asthma (EIA) is a transient increase in airway resistance after intensive exercise and can be measured as a decline in forced expiratory volume in one second (FEV1). The condition is due to increased training load and inhalation of cold and dry air. Several studies have shown that eucapnic voluntary hyperpnea challenge test (EVH test) is a very sensitive and specific diagnostic method. EVH test develops EIA by hyperventilation of dry gas and the test achieves the same airway obstruction as training in cold and dry air. The test is better than the previously used methacholine challenge test.

Acute, Inflammatory-based Airflow Limitation Does Not Affect Pulmonary Responses To Exercise In Asthmatic Subjects

PURPOSE: Exercise capacity is thought to be compromised in asthmatic subjects. This would especially be the case when exercise is preceded by significant airflow limitation in asthmatics who exhibit variable airway function on a day-to-day basis. The strong bronchodilatory effect of exercise, however, might minimize potential for pre-exercise airflow limitation to influence the responses to exercise. METHODS: Mild-to-moderate asthmatic subjects (n=9) completed exercise-to-exhaustion on a cycle ergometer (85% peak power) on three separate occasions: 1) following a eucapnic voluntary hyperpnea challenge (EVH), 2) a sham to the EVH (SHAM), and 3) a control trial of seated relaxation (CON). Pulmonary function was assessed at baseline and following each intervention. Metabolic rate, minute ventilation and its determinants, and spontaneous exercise flow-volume loops were analyzed at regular intervals during exercise. RESULTS: Subjects exhibited a 21% decrease in the forced expiratory volume 1.0 s (FEV1.0) following EVH (p<0.05 vs. CON and SHAM), and pre-exercise FEV1.0 was significantly lower during EVH compared to CON and SHAM (pre-exercise FEV1.0 = 3.8 ± 0.8, 3.8 ± 1.0, 3.2 ± 0.5 L for CON, SHAM, and EVH, respectively; p<0.05). During exercise, partial forced expiratory maneuvers demonstrated increases in expiratory flow rates compared to baseline during all trials, but the increased airflow was most marked during EVH. Exercise time-to-exhaustion was not different among the three trials (5.6 ± 1.6, 5.1 ± 1.5, 5.6 ± 2.4 minutes for CON, SHAM, and EVH). The ventilatory equivalent for metabolic carbon dioxide production (VE/VCO2), tidal volume to inspiratory capacity ratio (VT/IC), and exercise lung volumes (determined by IC maneuvers) were not different among the three trials. CONCLUSIONS: Acute, inflammatory-based airway dysfunction present immediately before exercise does not affect exercise ventilation or the airway mechanical responses to exercise in asthmatic subjects with mild-to-moderate disease. The powerful bronchodilatory response to exercise thus appears to override the airway dysfunction seen prior to exercise. Funding: Vermont Genetics Network, P20 RR16462 from the INBRE Program of the National Center for Research Resources, a component of the National Institutes of Health (NIH).

Diagnosis of exercise-induced bronchoconstriction: eucapnic voluntary hyperpnoea challenges identify previously undiagnosed elite athletes with exercise-induced bronchoconstriction

BackgroundThere is increasing evidence to suggest many elite athletes fail to recognise and report symptoms of exercise-induced bronchoconstriction (EIB), supporting the contention that athletes should be screened routinely for EIB.PurposeTo...