Eucapnic Voluntary Hyperventilation Test Research Articles

Activation of epithelial and inflammatory pathways in adolescent elite athletes exposed to intense exercise and air pollution

RationaleParticipation in high-intensity exercise in early life might act as stressor to the airway barrier.ObjectivesTo investigate the effect of intense exercise and associated exposure to air pollution on the airway...

High Prevalence of Exercise-induced Laryngeal Obstruction in a Cohort of Elite Cross-country Skiers.

ABSTRACTIntroductionExercise-induced laryngeal obstruction (EILO) is a differential diagnosis for asthma and prevalent in athletes referred for exercise-induced dyspnea. The aim of this study was to estimate the prevalence of EILO in elite cross-country skiers, known for a high prevalence of asthma.MethodElite cross-country skiers were invited for screening of EILO. Screening consisted of clinical assessment, questionnaires, skin prick test, spirometry, eucapnic voluntary hyperventilation test, and continuous laryngoscopy during exercise test. Current asthma was defined as physician-diagnosed asthma and use of asthma medication during the last 12 months. EILO was defined as ≥2 points at the supraglottic or glottic level during exercise at maximal effort, using a visual grade score system.ResultA total of 89 (51% female) cross-country skiers completed the study. EILO was identified in 27% of the skiers, 83% of whom were female. All skiers with EILO had supraglottic EILO, and there was no glottic EILO. Current asthma was present in 34 (38%) of the skiers, 10 (29%) of whom had concomitant EILO. In the skiers with EILO, a higher proportion reported wheeze or shortness of breath after exercise, compared with skiers without EILO. In skiers with EILO and current asthma, compared with skiers with asthma only, a higher proportion reported wheeze or shortness of breath after exercise. Asthma medication usage did not differ between these groups.ConclusionEILO is common in elite cross-country skiers, especially females. Asthma and EILO may coexist, and the prevalence of respiratory symptoms is higher in skiers with both. Testing for EILO should be considered in cross-country skiers with respiratory symptoms.

Eucapnic voluntary hyperventilation test decreases exhaled nitric oxide level in children.

Exhaled nitric oxide (FeNO) measurements and eucapnic voluntary hyperventilation (EVH) tests have been used as diagnostic tools for asthma. Data on the impact of hyperventilation on the level of FeNO are limited. We aimed to evaluate whether EVH tests affect the level of FeNO in children aged 10-16years. A total of 234 children aged 10-16years had a 6-min EVH test performed. In total, FeNO values for 153 of 234 children were measured before the test and within 15min after the test. According to a baseline FeNO level of 20ppb, children were divided into two groups: those with low values (FeNO<20ppb) and those with high values (FeNO≥20ppb). The median age of the children was 13.4years (interquartile range 12.3-15.3years); 58% were boys and 42% were girls. Of these children, 51% were sensitized to aeroallergens. In 101 of 153 children (66%), the FeNO values decreased after the EVH test. In children with low and high baseline levels, the median level of FeNO decreased after the EVH test: 10.5ppb before versus 9.5ppb after (p<.011), and 31.0ppb before versus 28.0ppb after (p<.011), respectively. The decrease in FeNO after EVH test was not associated with induced bronchoconstriction expressed as a change in FEV1 (Rs =.19). The EVH test decreases FeNO levels. Therefore, FeNO should be measured before an EVH test is performed.

Cut-off values to evaluate exercise-induced asthma in eucapnic voluntary hyperventilation test for children.

Background and AimThe eucapnic voluntary hyperventilation (EVH) testing is a diagnostic tool for diagnostics of exercise‐induced bronchoconstriction; while the testing has become more common among children, data on the test's feasibility among children remain limited. Our aim was to investigate EVH testing feasibility among children, diagnostic testing cut‐off values, and which factors affect testing outcomes.MethodsWe recruited 134 patients aged 10–16 years with a history of exercise‐induced dyspnoea and 100 healthy control children to undergo 6‐min EVH testing. Testing feasibility was assessed by the children's ability to achieve ≥70% of the target minute ventilation of 30 times forced expiratory volume in 1 s (FEV1). Bronchoconstriction was assessed as a minimum of 8%, 10%, 12%, 15% or 20% fall in FEV1. Patient characteristics were correlated with EVH outcomes.ResultsOverall, 98% of the children reached ≥70%, 88% reached ≥80%, 79% reached ≥90% and 62% reached ≥100% of target ventilation in EVH testing; of children with a history of exercise‐induced dyspnoea, the decline percentages were as follows: 24% (≥8% fall), 17% (≥10% fall), 10% (≥12% fall), 6% (≥15% fall) and 5% (≥20% fall) in FEV1, compared to 11%, 4%, 3%, 1% and 0% among the healthy controls, respectively. Healthy controls and boys performed testing at higher ventilation rates (p < .05).ConclusionEucapnic voluntary hyperventilation testing is feasible among children aged 10–16 years and has diagnostic value in evaluating exercise‐induced dyspnoea among children. A minimum 10% fall in FEV1 is a good diagnostic cut‐off value. Disease status appears to be important covariates.

EUCAPNIC VOLUNTARY HYPERVENTILATION FOR THE DIAGNOSIS OF EXERCISE-INDUCED BRONCHOSPASM IN A COMMUNITY SETTING

SESSION TITLE: Wednesday Abstract Posters SESSION TYPE: Original Investigation Posters PRESENTED ON: 10/23/2019 09:45 AM - 10:45 AM PURPOSE: Exercise-induced bronchospasm (EIB) is a common and well-known condition affecting 5% to 20% of the general population and up to 90% of patients with symptomatic asthma. EIB tends to be treated in a community setting based on symptoms without objective findings of bronchospasm. Eucapnic voluntary hyperventilation (EVH) has been established as a sensitive test to diagnose EIB in elite athletes enrolled in research settings or in University based academic medical centers. However, clinical utility of EVH in a community practice setting has not yet been fully demonstrated. We evaluated the feasibility and performance of EVH as a diagnostic test for EIB in a community based pulmonary clinic. METHODS: Retrospective analysis of 22 EVH tests performed for evaluation of EIB symptoms. All tests were done in the pulmonary clinic at The Oregon Clinic using a standard protocol (Anderson SD, Br J Sport Med 2001). Patients underwent baseline spirometry followed by breathing a gas mixture of 5% CO2, 74% N, and 21% O2 at a target minute ventilation (35 x FEV1) for 6 minutes. Spirometry was performed at 3, 5, 10, 15, and 20 minutes. An EVH test was considered sufficient if maximum voluntary ventilation per minute (MVV) >60%. A positive test was defined as >10% decrease in any post-EVH FEV1. RESULTS: 22 patients completed EVH with 21/22 (95.4%) able to achieve MVV >60%. Mean age was 37 years, with a range of 15-71. 59% of patients were female. 4/21 (19%) of patients had a positive test for EIB. Abnormal inspiratory flow volume loops were found in 11 (50%) of patients, suggestive of vocal cord dysfunction (VCD). Videolaryngoscopy (VLS) was subsequently performed on 9 of these 11 patients, with 100% (9/9) (+) for exercise induced VCD (EIVCD) .One patient had a (+) EVH for EIB and an abnormal flow volume loop with a subsequent (+) VLS for EIVCD. CONCLUSIONS: Eucapnic Voluntary Hyperventilation has, to this point, largely been used in research and University academic medical centers to diagnose EIB. Our data suggests that EVH can be utilized successfully in a community based practice setting with the majority of athlete and non-athlete patients able to complete the test with sufficient MVV. Only 19% of patients presenting with symptoms consistent with EIB, were objectively diagnosed with EIB via EVH. This suggests EIB may be over diagnosed in the community setting based on symptoms alone. 50% of the patients evaluated with an EVH test had abnormal flow volume loops with 80% of these patients (+) for EIVCD via VLS testing. CLINICAL IMPLICATIONS: Thus, our data suggests that EVH is an acceptable diagnostic modality for EIB in a community setting, and may be useful in diagnosing alternative conditions such as EIVCD causing similar symptoms. DISCLOSURES: No relevant relationships by Crystal Clark, source=Web Response No relevant relationships by Jordan Lauw, source=Web Response No relevant relationships by John Mastronarde, source=Web Response No relevant relationships by Brandon Temte, source=Web Response No relevant relationships by Jason Wells, source=Web Response

Comparison of impulse oscillometry and spirometry for detection of airway hyperresponsiveness to methacholine, mannitol, and eucapnic voluntary hyperventilation in children.

Forced expiratory maneuvers are usually difficult in young children. Impulse oscillometry (IOS) requires no active cooperation, is noninvasive, rapid, and easy to perform. This study aimed to compare IOS indexes and forced expiratory volume in 1 second (FEV1) in children for the assessment of bronchial hyperreactivity to methacholine, mannitol, and eucapnic voluntary hyperventilation (EVH). Children aged 3-14 years (mean 10.0 ± 3.1) with symptoms suggestive of asthma were recruited. IOS measurements were taken before spirometry. Methacholine, mannitol, and EVH tests were performed without a specific order. We included 190 children, whose mean age was 10.0 ± 3.1 years. Changes in FEV1 correlated significantly with variation in IOS indexes (P < .05). The indexes with the greatest discriminative capacity were Z5, R5, and X5. Optimal cut-offs were: for methacholine tests, ≧22% in R5, ≧82% for reactance area (AX), and ≦41% for X5; for the mannitol test, ≧18% in R5, ≧40% in AX, and ≦21% for X5. In the EVH test, ≧23% for R5, ≧40% for AX, and a fall of 29% for X5. When using the optimal cut-off points obtained from IOS, the mean number of steps and doses required for methacholine and mannitol tests to induce significant bronchoconstriction were significantly lower compared with spirometry ( P < .05). The effectiveness of R5, X5, and AX indexes were comparable to FEV1 in assessing bronchial obstruction during bronchial challenge testing. Therefore, IOS may be useful in assessing bronchial obstruction in children who cannot reliably perform spirometric maneuvers during bronchial challenge testing.

Eucapnic voluntary hyperventilation test in children.

In children, exercise-induced dyspnea is a common symptom that can be due to dysfunctional breathing. EVH test has bee used especially in elite athletes as bronchoprovocation test. Currently, there are only few studies on the EVH test. New research methods are required alongside the traditionally used tests especially due to dysfunctional breathing disorder. The purpose of the "pilot study" was to study the usability of the EVH test with real time biofeedback in children of 10-16years of age in the diagnostics of exercise-induced dyspnea. Six 10-16-year-old teenagers with history of exercise-induced dyspnea and three healthy control subjects were selected for the study. A 6-minute EVH test with realtime biofeedback was performed on the patients and the diagnosis was confirmed on the basis of clinical findings and spirometry follow-up either as normal, asthma or dysfunctional breathing. The study was successful in the patients. In the spirometry follow-up, three patients had bronchoconstriction (FEV1 decline over 10%), dysfunctional breathing condition was observed in three patients and three control patients experienced no symptoms. Only two DFB-patients didn't reach the target level of minute ventilation due to a clinical symptom (inspiratory stridor). The EVH test was successful in the 10-16-year-old children having participated in the study and the test was well tolerated. Through the study, it was possible to provoke both dysfunctional breathing disorder and bronchoconstriction in the symptomatic patients. Based on the pilot study, EVH test seems to be usable in the diagnostics of pediatric exercise-induced dyspnea but larger studies are warranted to confirm our preliminary findings.

Vitamin D deficiency and exercise-induced laryngospasm in young competitive rowers.

Exercise-induced dyspnea is common among adolescents and young adults and often originates from exercise-induced bronchoconstriction (EIB). Sometimes, dyspnea corresponds to exercise-induced laryngospasm (EILO), which is a paradoxical decrease in supraglottic/glottic area. Vitamin D deficiency, which occurs frequently at northern latitudes, might favor laryngospasm by impairing calcium transport and slowing striate muscle relaxation. The aim of this study was to evaluate whether vitamin D status has an influence on bronchial and laryngeal responses to exercise in young, healthy athletes. EIB and EILO were investigated during winter in 37 healthy competitive rowers (24 males; age range 13-25 years), using the eucapnic voluntary hyperventilation test (EVH). EIB was diagnosed when forced expiratory volume in the first second decreased by 10%, EILO when maximum mid-inspiratory flow (MIF50) decreased by 20%. Most athletes (86.5%) had vitamin D deficiency (below 30 ng/mL), 29 mild-moderate (78.4%) and 3 severe (8.1%). EVH showed EIB in 10 subjects (27%), EILO in 16 (43.2%), and combined EIB and EILO in 6 (16.2%). Athletes with EILO had lower vitamin D (19.1 ng/mL vs. 27.0 ng/mL, p < 0.001) and higher parathyroid hormone (30.5 pg/mL vs. 19.2 pg/mL, p = 0.006) levels. The degree of laryngoconstriction (post-EVH MIF50 as a percentage of pre-EVH MIF50) was related directly with vitamin D levels (r = 0.51; p = 0.001) and inversely with parathyroid hormone levels (r = -0.53; p = 0.001). We conclude that vitamin D deficiency is common during winter in young athletes living above the 40th parallel north and favors laryngospasm during exercise, probably by disturbing calcium homeostasis. This effect may negatively influence athletic performance.

Feasibility to apply eucapnic voluntary hyperventilation in young elite athletes

Introduction: Exercise-induced bronchoconstriction (EIB) is more common in athletes compared to the general population. The eucapnic voluntary hyperventilation test is used to detect EIB in adult athletes. It is however unclear whether this technique is also applicable to young athletes.MethodsYoung athletes (basketball (n = 13), football (n = 19), swimming (n = 12)) were recruited at the start of their elite sports career (12–14 years). Eight age-matched controls were also recruited. Eucapnic voluntary hyperventilation test was performed according to ATS guidelines in all subjects. A second (after 1 year, n = 32) and third (after 2 years, n = 39) measurement was performed in a subgroup of athletes and controls.ResultsAt time of first evaluation, 3/13 basketball players, 4/19 football players, 5/11 swimmers and 1/8 controls met criteria for EIB (fall in FEV1≥10% after EVH). A ventilation rate of >85% of the maximal voluntary ventilation (MVV) is recommended by current guidelines (for adults) but was only achieved by a low number of individuals (first occasion: 27%, third occasion: 45%) However, MVV in young athletes corresponds to 30 times FEV1, which is equivalent to 85% of MVV in adults. A threshold of 70% of MVV (21 times FEV1) is feasible in the majority of young athletes.ConclusionEIB is present in a substantial number of individuals at the age of 12–14 years, especially in swimmers. This underscores the importance of screening for EIB at this age. EVH is feasible in young elite athletes, however target ventilation needs to be adjusted accordingly.

Eucapnic voluntary hyperpnoea and exercise-induced vocal cord dysfunction

IntroductionExercise-induced bronchoconstriction (EIB) is a common condition in endurance athletes. Exercise-induced vocal cord dysfunction (EIVCD) is a frequent confounder of EIB. The diagnosis of EIVCD may be challenging and can...

Eucapnic Voluntary Hyperventilation to Detect Exercise-Induced Bronchoconstriction in Cystic Fibrosis.

Exercise-induced bronchoconstriction (EIB) has not been well studied in cystic fibrosis (CF), and eucapnic voluntary hyperventilation (EVH) testing has not been used as an objective assessment of EIB in CF to date. A prospective cohort pilot study was completed where standard EVH testing was completed by 10 CF patients with forced expiratory volume in 1 s (FEV1) ≥70% of predicted. All patients also completed a cardiopulmonary exercise test (CPET) with pre- and post-CPET spirometry as a comparative method of detecting EIB. No adverse events occurred with EVH testing. A total of 20% (2/10) patients were diagnosed with EIB by means of EVH. Both patients had clinical symptoms consistent with EIB. No patient had a CPET-based exercise challenge consistent with EIB. EVH testing was safe and effective in the objective assessment for EIB in patients with CF who had well-preserved lung function. It may be a more sensitive method of detecting EIB then exercise challenge.

Eucapnic voluntary hyperventilation in diagnosing exercise-induced laryngeal obstructions

Exercise-induced laryngeal obstructions (EILOs) cause exercise-related respiratory symptoms (ERRS) and are important differential diagnoses to exercise-induced asthma. The diagnostic method for EILOs includes provocation to induce the obstruction followed by a verification of the obstruction and the degree thereof. The objective of the present study was to examine if a eucapnic voluntary hyperventilation (EVH) test could induce laryngeal obstructions laryngoscopically identical in subtypes and development as seen during an exercise test. EVH and exercise testing with continuous laryngoscopy were performed during a screening of two national athletic teams (n = 67). The laryngoscopic recordings were examined for usability, abnormalities and maximal supraglottic and glottic obstruction using two currently available methods (Eilomea and CLE-score). The participants were asked questions on ERRS, and whether the symptoms experienced during each provocation matched those experienced during regular training. A total of 39 completed both tests. There were no significant differences in subtypes and development thereof, the experience of symptoms, and specificity and sensitivity between the methods. Significantly more recordings obtained during the exercise test were usable for evaluation primarily due to resilient mucus on the tip of the fiber-laryngoscope in the EVH test. Only recordings of six athletes from both provocation methods were usable for evaluation using the Eilomea method (high-quality demand). Amongst these, a linear correlation was found for the glottic obstruction. EVH tests can induce EILOs. However, the present test protocol needs adjustments to secure better visualisation of the larynx during provocation.

Airway Dysfunction and Inflammation in Pool- and Non–Pool-Based Elite Athletes

This study sought to determine and compare the levels of airway dysfunction and inflammation in a large cohort of symptomatic international athletes from pool- and non-pool-based sporting backgrounds. In total, 118 athletes were recruited. All subjects had symptoms of exercise asthma and were steroid naïve. They completed baseline spirometry, a symptom score, exhaled nitric oxide, a eucapnic voluntary hyperventilation (EVH) test, and a postchallenge induced sputum and urine test. Pool-based athletes had better lung function (FEV1 = 110% vs 102% predicted, mean difference = 8.200 ± 2.339, P = 0.0006 and FVC = 5.64 vs 4.75 L, mean difference = 0.8855 ± 0.1951, P < 0.0001) and more marked airways hyper-reactivity (AHR) (percent drop in FEV1 after EVH = 18.14 vs 11.47, mean difference = 6.67, 95% confidence interval = 2.89-10.53, P = 0.0009). More pool-based athletes had a positive EVH test (72% pool vs 39% nonpool), but there was no difference between groups with respect to eosinophilic inflammation (sputum eosinophil percentage: pool = 2.07, nonpool = 2.28, P = 0.77; exhaled nitric oxide: pool = 32.54, nonpool = 35.77, P = 0.60). Athletes with a positive EVH test had less neutrophilic inflammation (P = 0.01) and more epithelial cells (P = 0.03) in their sputum. Pool-based endurance athletes have greater evidence of AHR than non-pool-based athletes but no evidence of greater eosinophilic airway inflammation. Athletes who test positive on EVH are more likely to be eosinophilic and have higher levels of epithelial cells in their sputum.

Screening for Exercise-Induced Bronchoconstriction in College Athletes

Objective. Previous studies have reported that the prevalence of exercise-induced bronchoconstriction (EIB) in athletes is higher than that of the general population. There is increasing evidence that athletes fail to recognize and report symptoms of EIB. As a result, there has been debate whether athletes should be screened for EIB, particularly in high-risk sports. Methods. We prospectively studied 144 athletes from six different varsity sports at a large National Collegiate Athletic Association Division I collegiate athletic program. Baseline demographics and medical history were obtained and the presence of asthma symptoms during exercise was documented. Each athlete subsequently underwent a eucapnic voluntary hyperventilation (EVH) test to document the presence of EIB. Exhaled nitric oxide (eNO) quantification was performed immediately before EVH testing. EIB was defined as a ≥10% decline in forced expiratory volume in 1 second compared with baseline. Results. Only 4 of 144 (2.7%) athletes were EIB-positive after EVH testing. The presence of symptoms was not predictive of EIB as only 2 of the 64 symptomatic athletes (3%) were EIB-positive based on EVH testing. Two of the four athletes who were found to be EIB-positive denied such symptoms. The mean baseline eNO in the four EIB-positive athletes was 13.25 parts per billion (ppb) and 24.5 ppb in the EIB-negative athletes. Conclusions. Our data argue that screening for EIB is not recommended given the surprisingly low prevalence of EIB in the population we studied. In addition, the presence or absence of symptoms was not predictive of EIB and eNO testing was not effective in predicting EIB.

The Diagnosis of Asthma and Exercise-Induced Bronchospasm in Division I Athletes

To determine the accuracy of clinically diagnosed exercise-induced bronchospasm (EIB) and asthma among National Collegiate Athletic Association Division I student athletes. Cohort study. Division I university athletic department and primary care sports medicine clinic/athletic training room. All varsity athletes were eligible for the study. Seventy-five participants entered the study; 74 completed all the study protocols. Study participants underwent measurement of exhaled nitric oxide (eNO), followed by baseline spirometry. Eucapnic voluntary hyperventilation (EVH) was then performed, followed by spirometry every 3 minutes for a total of 21 minutes to measure change in forced expiratory volume in 1 second. Exhaled nitric oxide levels, baseline spirometry, and response of forced expiratory volume in 1 second to EVH. There were a total of 16 subjects with a positive EVH test. There were 16 (80%) individuals using a bronchodilator who had a negative EVH test versus 4 (20%) who had a positive test. Mean eNO values were different across subject groups defined by treatment status, although not statistically significant. The highest mean eNO value of 24.32 ppb was found in subjects only taking bronchodilators compared with the lowest mean value of 16.75 ppb in athletes who were not taking any medications. The results from this study provide further evidence to support the need for objective testing to correctly diagnose EIB. These data suggest that measuring eNO may help to distinguish truly isolated EIB from asthma in athletes, but a larger study is needed to confirm these initial observations.

The Clinical Utility of Eucapnic Voluntary Hyperventilation Testing for the Diagnosis of Exercise-Induced Bronchospasm

Background. Exercise-induced bronchospasm (EIB) is the acute, transient airway narrowing associated with exercise. Eucapnic voluntary hyperventilation (EVH) has been used to diagnose EIB in elite athletes and in research settings. The clinical utility of EVH in a general pulmonary practice has not previously been reported. Thus we sought to determine the utility and applicability of EVH testing in the clinical setting. Methods. We retrospectively analyzed 178 EVH tests performed at the Ohio State University Medical Center. Results. A total of 178 EVH studies were performed. Fifty patients (28%) were EIB-positive. A threshold of 60% of the predicted maximum voluntary ventilation (MVV) per minute was used as a criterion for an adequate EVH test. A majority of patients, 127 (71%), had adequate EVH tests. Females were less likely to achieve 60% MVV than males (80% vs. 55%; p = 0.002). Of the 51 patients with inadequate tests, 17 (33%) were EIB-positive; 16 of these 17 were female. Overall, EVH testing was diagnostic in 144 of 178 (81%) of patients tested. Conclusions. We present the first description of the clinical use of EVH testing for the diagnosis of EIB in a large pulmonary practice. EVH was diagnostic in a large majority of patients. EVH is an excellent and feasible modality to diagnose EIB in patients seen in a general pulmonary practice. Our data highlight the need for further studies regarding the appropriate minimum threshold minute ventilation for an EVH test and to explain potential mechanisms for seemingly different stimulus thresholds for bronchospasm in males versus females.

Airway Inflammation in Exercise-Induced Bronchospasm Occurring in Athletes Without Asthma

Exercise-induced bronchospasm (EIB) occurs in athletes with and without asthma. Studies have suggested an inflammatory basis for EIB in asthmatics; however whether inflammation plays a similar role in EIB in athletes without asthma remains unclear. Our objective was to determine whether there is evidence of an inflammatory basis for exercise-induced bronchospasm occurring in non-asthmatic athletes._Ninety-six athletes without asthma from varsity college teams underwent eucapnic voluntary hyperventilation testing. Sputum was induced from subjects with hypertonic saline inhalation post-eucapnic voluntary hyperventilation testing and was analyzed with enzyme-linked immunosorbent assays for IL-5, IL-8, IL-13, cysteinyl-leukotrienes, prostaglandin E2, histamine, leukotriene B4, and thromboxane B2. In addition, inflammatory (neutrophils, lymphocytes, eosinophils, and macrophages) and epithelial cell counts in sputum were recorded._Multivariate regression modeling showed a significant correlation between concentrations of select inflammatory mediators after eucapnic voluntary hyperventilation testing and severity of EIB. Means of the log-transformed concentrations of inflammatory mediators in EIB-positive athletes were significantly higher post-eucapnic voluntary hyperventilation than in EIB-negative athletes. Similar findings were not demonstrated with inflammatory cells._Concentrations of inflammatory mediators are higher in EIB-positive athletes than in EIB-negative athletes without asthma after eucapnic voluntary hyperventilation testing. The severity of EIB in our cohort also is significantly correlated with increased concentrations of select inflammatory mediators suggesting a potential inflammatory basis for EIB in athletes without asthma.

Influence of Body Fat on Exercise-Induced Bronchoconstriction

The prevalence of obesity and asthma (including exercise-induced bronchoconstriction, EIB) are both increasing in the United States. While previous research suggests a link between obesity and EIB, the effect of body fat on airway hyper-reactivity following exercise is not known. PURPOSE: To determine the effect of body fat on airway function in subjects with EIB. METHODS: Thirteen subjects (4 men, 9 women) with EIB (determined by ≥10% decrease in FEV1 following an exercise bout and a eucapnic voluntary hyperventilation test: EVH) were divided into three groups (high fat HF, n=5; moderate fat MF, n=4; low fat LF, n=4) based on total body fat (g) relative to height (HF 161.4 ± 19.5; MF 117.5 ± 8.5; LF 63.5 ± 9.9 g/cm; p <0.05) determined via Dual Energy X-ray Absorptiometry (DXA; Lunar). Pulmonary function tests (PFT) and exhaled nitric oxide (ENO; Sievers) were determined in triplicate pre and post (min 5, 15, 30) exercise. Subjects completed a constant load eight minute exercise test on a cycle ergometer at a workload based on a target ventilation of ∼50–60% predicted maximal voluntary ventilation while breathing dry air. RESULTS: There were no differences (P > 0.05) between groups in PFT or ENO at rest, or in metabolic or ventilatory variables during exercise. However, the decrease in FEV1 from baseline to 5 minutes post exercise was less (p <0.05) in MF (−15.5 ± 1.4%) compared to both LF (−28.5 ± 6.6%) and HF (−31.2 ± 1.4%). Also, at 5 minutes post exercise, the decrease in ENO was significantly greater in HF (−18.6 ± 2.7%) vs. MF (−8.8 ± 2.5%). There was no difference (P > 0.05) at min 15 or 30 post exercise in any variable. CONCLUSION: These data suggest that, for our population, both high and low body fat lead to greater airway narrowing following exercise in subjects with EIB compared to subjects with moderate body fat amounts. The mechanism responsible may be a greater bronchoprotective role of airway nitric oxide in moderately fat individuals.

Field Exercise vs Laboratory Eucapnic Voluntary Hyperventilation To Identify Airway Hyperresponsiveness in Elite Cold Weather Athletes

For the 2002 Winter Olympic Games, athletes were required to submit objective evidence of asthma or exercise-induced bronchoconstriction (EIB) for approval to inhale a beta(2)-agonist. Eucapnic voluntary hyperventilation (EVH) was recommended as a laboratory challenge that would identify airway hyperresponsiveness (AHR) consistent with EIB. The objective was to compare the change in FEV(1) provoked by EVH with that provoked by exercise in cold weather athletes. Spirometry was measured before and for 15 min after challenges. The two challenges were performed in random order at least 24 h apart. EVH was performed in the laboratory at 19 degrees C, and exercise took place in the field in the cold (2 degrees C, 45% relative humidity). Thirty-eight athletes (25 female subjects; median age, 16 years). For the EVH, athletes inhaled dry air containing 5% carbon dioxide for 6 min at a target ventilation equivalent to 30 times baseline FEV(1). Exercise was performed by cross-country skiing, ice skating, or running for 6 to 8 min. AHR consistent with EIB was defined as >or= 10% fall in FEV(1) from baseline after challenge. Eleven athletes were exercise positive (EX+) [FEV(1) fall, 20.5 +/- 7.3%], and 17 athletes were EVH positive (FEV(1) fall, 14.5 +/- 4.5%) [mean +/- SD]. Of 19 subjects with AHR, 58% were identified by exercise and 89% were identified by EVH. EVH identified 9 of 11 subjects who were EX+ and a further 8 subjects with potential for EIB. The average ventilation during EVH was 28 times FEV(1). Performing EVH for 6 min in the laboratory had a greater chance of identifying AHR in these athletes compared with 6 to 8 min of field exercise in the cold. The EVH test will be useful to evaluate elite summer sports athletes whose widely different forms of exercise provide an "equipment" challenge to any laboratory.

A Comparison of Two Challenge Tests for Identifying Exercise-Induced Bronchospasm in Figure Skaters

Studies documenting the increased incidence of exercise-induced bronchospasm (EIB) in figure skaters have employed a method that incorporates on-ice exercise with rink-side spirometry. The literature suggests that bronchial provocation challenge testing is better than exercise testing for identifying EIB. To test this hypothesis in figure skaters, a unique athletic population that trains and competes in cold air, we compared these two methods in the same individuals. Two challenge tests were performed on a group of competitive figure skaters (n = 29, 26 female subjects; mean+/-SD age = 12.3+/-3.5 years): (1) rink-side (temperature = 14 degrees C, humidity = 60%) spirometry before and 1, 5, 10, and 15 min after 5 min of intense skating; and (2) eucapnic voluntary hyperventilation (EVH), breathing 5% CO2, 21% O2, balance N2 at a rate of 60% of maximum voluntary ventilation (not to exceed 70 L/min) for 5 min (temperature = 18 degrees C, humidity = 50%), with an identical pretest and posttest spirometry schedule. EIB was defined as at least one of the following: a > or =10% decline in Fev1; a > or = 20% decline in maximum midexpiratory flow rate; or a > or = 25% decline in peak expiratory flow rate. Sixteen of 29 skaters (55%) developed EIB: 9 were positive by on-ice testing; 12 were positive by EVH testing; 5 were positive on both tests; on-ice testing missed 7 skaters with EIB; EVH testing missed 4 with EIB. In the group of figure skaters studied, EVH challenge testing was better at identifying EIB than on-ice exercise testing. However, these data suggest that evaluation for EIB in athletes who train and compete in the cold should include exercise testing in cold air along with a challenge test such as EVH to increase the yield of positive responders.