Severity Of Exercise-induced Bronchoconstriction Research Articles

Association of temperature and absolute humidity with incidence of exercise-induced bronchoconstriction in children.

Exercise test outdoors is widely used to diagnose asthma in children, but it is unclear how much outdoor air factors affect the results. We analysed 321 outdoor exercise challenge tests with spirometry in children 6-16 years conducted due to suspicion of asthma or for assessing the effect of medication on asthma. We studied the association of FEV1 decrease and incidence of exercise-induced bronchoconstriction (EIB) with temperature, relative humidity (RH) and absolute humidity (AH). Asthma was diagnosed in 57% of the subjects. AH ≥5 g/m3, but not RH or temperature, was associated with the EIB incidence (p = 0.035). In multivariable logistic regression, AH ≥5 g/m3 was negatively associated (OR = 0.51, 95% CI [0.28─0.92], p = 0.026) while obstruction before exercise (OR = 2.11, 95% CI [1.16─3.86], p = 0.015) and IgE-mediated sensitisation were positively associated with EIB (OR = 2.24, 95% CI [1.11─4.51], p = 0.025). AH (r = -0.12, p = 0.028) and temperature (r = -0.13, p = 0.023) correlated with decrease in FEV1. In multivariable linear regression, only AH was associated with FEV1 decrease (coefficient = -0.044, 95% CI [-0.085 to -0.004], p = 0.033). AH of outdoor air associates with occurrence and severity of EIB in outdoor exercise tests in children. Care should be taken when interpreting negative outdoor exercise test results if AH of air is high.

Exercise-induced bronchoconstriction is associated with air humidity and particulate matter concentration in preschool children.

Long-term exposure to air pollution is connected to asthma morbidity in children. Exercise-induced bronchoconstriction (EIB) is common in asthma, and the free running test outdoors is an important method for diagnosing asthma in children. It is not known whether momentary air pollution exposure affects the results of outdoor exercise tests in children. We analyzed all reliable exercise challenge tests with impulse oscillometry in children (n = 868) performed between January 2012 and April 2015 at Tampere University Hospital. Pollutant concentrations (PM2.5 , NO2 , and O3 ) at the time of the exercise test were collected from public registers. We compared the pollutant concentrations with the proportion and severity of EIB and adjusted the analyses for air humidity and pollen counts. Pollution levels were rarely high (median PM2.5 6.0 µg/m3 , NO2 12.0 µg/m3 , and O3 47.0 µg/m3 ). The relative change in resistance at 5 Hz after exercise did not correlate with O3 , NO2 or PM2.5 concentrations (p values 0.065-0.884). In multivariate logistic regression, we compared the effects of PM2.5 over 10 µg/m³, absolute humidity (AH) over 10 g/m³ and alder or birch pollen concentration over 10 grains/m³. High (over 10 g/m3 ) AH was associated with decreased incidence (OR 0.31, p value 0.004), and PM2.5 over 10 µg/m³ was associated with increased incidence (OR 1.69, p value 0.036) of EIB. Even low PM2.5 levels may have an effect on EIB in children. Of the other properties of air, only AH was associated with the incidence of EIB.

High Incidence of Bronchospastic Response to a Stair Climbing Exercise.

BackgroundWhile it is increasingly recognized that exercise-induced bronchoconstriction (EIB) affects a substantial proportion of sport participants, the relation of EIB incidence and severity to the type and intensity of exertion remains under-investigated. The aim of this study was to establish the incidence and severity of EIB during a stair race, a highly demanding all-out effort exercise. We hypothesized that a large proportion of participants would develop EIB to this particular high-intensity competition, and that among the predisposing factors, severity of EIB would depend on the level of exertion.MethodologyIn this study, screening for EIB was conducted during the official competitive race to a 114-m skyscraper held during the late spring in a city center of approximately 0.5 million residents. Healthy active men (n = 26; age = 32.0 ± 7.0 years) volunteering for the study from the field of the race were included. Allergy Questionnaire for Athletes was completed, and responses of expiratory capacity (forced expiratory volume in the first second, FEV1) and blood lactate were measured by portable digital devices.ResultsOn average, FEV1 dropped by 10.5 ± 5.6% after the exercise. In 11 (approximately 42.5%) participants, FEV1 drop was >10%, indicative of clinical EIB. While age, anthropometry, training experience, allergy history, baseline FEV1, and post-exercise lactate did not differ in responders versus non-responders, those with FEV1 decrement of >10% were slower in the race.ConclusionsDue to very high incidence of EIB observed in active men performing a maximal-effort task and negative association of EIB with competitive performance, the condition of these individuals undertaking regular intense exercise deserves more attention.

Leptin and exercise-induced bronchoconstriction in obese asthmatic children

Exercise-induced bronchoconstriction (EIB) in asthmatic children has been associated with obesity. Leptin, the proinflammatory adipokine, is typically increased in obesity, whereas cysteinyl leukotrienes (cysLTs) are the main inflammatory mediators implicated in the pathogenesis of EIB. The aim of this work was to study the possible impact of obesity on the severity of EIB in asthmatic children and the possible association with the adipokine leptin. The study included eighty pre-pubertal asthmatic children divided according to their body mass index (BMI) and response to exercise into four groups; obese exercise-responders (n=20), normal-weight exercise-responders (n=20), obese exercise non-responders (n=20), and normal-weight exercise non-responders (n=20). A baseline spirometry test and a standardized exercise challenge test (ECT) were performed. The severity of EIB was assessed by the maximum percentage fall in forced expiratory volume in 1 second (MF%FEV1) after exercise. The level of fasting serum leptin and the release of cysLTs during exercise were compared between the 4 groups. The MF%FEV1 during exercise was significantly greater in obese responder compared to normal-weight responder patients (p=0.004) and MF%FEV1 was positively correlated with cysLT release during exercise, BMI z-score, waist circumference and serum leptin. CysLT release during exercise was positively correlated with the level of serum leptin (r =0.514, p=0.001). This study reports that the severity of EIB is significantly greater in obese compared to normal-weight asthmatic children and suggests an association between leptin and airway hyperresponsiveness to exercise in obese asthmatic children through a mechanism related to cysLT release

Does The Mixed Relay Triathlon Affect Respiratory Function In Healthy Junior Triathletes?

Exercise-induced bronchoconstriction (EIB) is a transient narrowing of the airway that can be attributed to heavy ventilation associated with sustained high intensity exercise greater than 8 min. High aerobic and ventilatory training demands can exacerbate the EIB response and lead to prevalence of EIB in endurance athletes like triathletes. The mixed relay triathlon, due to its high intensity and short duration format, will induce heavy ventilation that could lead to EIB. However, no research at present has determined the influence of a mixed relay on respiratory function and baseline spirometry measures which influence EIB. PURPOSE: To determine severity and prevalence of EIB in healthy triathletes competing in a mixed relay and understand if baseline spirometry is predictive of the EIB response and race performance. METHODS: Seven males (17.7 ± 0.4 years, 183.7 ± 3.0 cm) and 5 females (17.6 ± 0.6 years, 171.1 ± 2.7 cm) competed in the Canadian Championships (300m swim, 6km bike, 1.6km run). Spirometry measures of Forced Expiratory Volume in 1 sec (FEV1), Forced Vital Capacity (FVC), FEV1/FVC (%), Forced Expiratory Flow at 50% FVC (FEF50), FEF 25-75% and Peak Expiratory Flow (PEF) was performed before warm up and 5 min post-race. Measures were calculated as % delta change (for EIB determination) and in raw units to determine pre-post differences in measures via paired sample t-tests. RESULTS: Mean race time was 22.4 ± 1.5 min including transitions (swim 4.5 ± 0.5 min, bike 10.4 ± 0.7 min, run 6.1 ± 0.6 min). No spirometry measure was significantly decreased post-race. One athlete had mild EIB (% decrease in FEV1 between 10 and 25%) and 2 athletes had a baseline FEV1/FVC ratio <0.7. Percent delta change in PEF and FEF 25-75% were correlated to finish time (r=-0.78, r=-0.83, p<0.05 respectively). CONCLUSION: An all-out 20 min ultra-short triathlon does not negatively affect respiratory function in young healthy junior triathletes. It maybe that the decrease in PEF and FEF 25-75 affected finish time due to reduced airway function affecting exercise intensity. The low prevalence of EIB compared to older endurance athletes supports the late onset of EIB in endurance athletes (> 25 years) although the 2 athletes with <0.7 resting FEV1/FVC ratios show signs of underlying airway obstruction.

Sex Differences in the Prevalence and Severity of Exercise-Induced Bronchoconstriction in Kindergarteners in Japan.

BackgroundExercise‐induced bronchoconstriction (EIB), a strong positive predictor of asthma, becomes progressively less frequent with age. Although asthma tends to become less common only in boys during adolescence, sex differences in EIB, especially in preschoolers, remain unclear. To find EIB for early diagnosis and intervention asthma, mass‐screening tests considering sex differences in preschoolers are needed. In this study, we investigated whether sex differences influence the prevalence and severity of EIB in prepubertal children aged 5–6 years.MethodsFifty‐one children aged 5–6 years who were attending a kindergarten in Matsuyama City, Ehime, Japan, were enrolled in this cross‐sectional study. The children underwent a 6‐minute free‐running test in 2015. The peak expiratory flow rate (PEFR) was measured before exercise and 0, 3, 10, and 20 minutes after exercise. The severity of EIB was classified according to the reduction in PEFR, measured as the difference between the postexercise PEFR and the highest pre‐exercise PEFR.ResultsOf the 51 children (23 boys and 28 girls) enrolled, the prevalence of EIB defined as three criteria: a ≥15%, ≥20%, or ≥25% decrease was 54.9% (28/51), 41.2% (21/51), and 25.5% (13/51), respectively. The prevalence of EIB defined as ≥25% decrease was significantly higher in girls than in boys (39.3% vs 8.7%, P = .013). In girls, the mean percentage change in PEFR was significantly higher 20 minutes than 10 minutes postexercise (P = .043).ConclusionsSex difference in the prevalence and severity of EIB should be considered when evaluating EIB, even in young, prepubertal children.

Prevalence of Exercise Induced Bronchoconstriction in Recreational Adult Hockey Players as determined by Sport Specific Field Exercise Challenge Test

BACKGROUND: Exercise induced bronchoconstriction (EIB) is provoked by exercise and results in narrowing of the airways. Studies have shown an EIB prevalence of 11-50% in athletic populations. The diagnosis of EIB is dependent upon objective measurement of respiratory function, as respiratory symptoms are unreliable. Cold and dry ambient conditions contribute to the severity of EIB. The environmental conditions and manner of exertion an athlete is exposed to in ice hockey are significantly different than any current standardized laboratory test to evaluate for EIB. In a prior study of elite women hockey players, 39.5% presented symptoms of asthma and 21% demonstrated EIB. Sport-specific field exercise challenge tests (SSFECT) have been validated for the assessment of EIB, and are more sensitive than laboratory challenges in elite winter athletes. PURPOSE: To use a SSFECT to determine the prevalence of EIB in adult recreational ice hockey players, and the correlation between reported symptoms and diagnosis by this method. METHODS: Participants were 18 males and 2 females (mean age of 34.7 yrs, mean height of 1.78 m); who participated in 1 of 2 recreational ice hockey leagues in Chicago, IL. Using a Piko-1 portable spirometer, FEV1 was measured prior to the hockey game and immediately following periods 1, 2, and 3. All respiratory measurements occurred with hockey equipment adorned. Airway response was expressed as the percent fall in FEV1 from the baseline value. Diagnosis of EIB was given if athletes had a greater than 10% decrease in FEV1 from baseline measured at any time point. Athletes also completed an intake questionnaire prior to testing which included clinical symptoms, exercise history, and past medical history. RESULTS: EIB was diagnosed in 3/20(15%) athletes. A prior diagnosis of asthma or exercise induced asthma was reported in 5/20 (25%) athletes, yet only one of these had a decrease of > 10 % of FEV1 as measured by this test. Of the three EIB+, two were symptomatic (67%); and of the EIB-, 9/17 (53%) reported respiratory symptoms. Diagnosis of EIB was consistent for all three periods in all but one athlete. Mean FEV1 for the three periods was 4.08, 4.07, and 4.07 respectively. CONCLUSIONS: Symptoms remain unreliable for diagnosis of EIB. SSFECT can be utilized for diagnosis of EIB in ice hockey athletes.

Exercise and Asthma.

Transient airway narrowing can occur during or following exercise, a phenomenon called exercise-induced bronchoconstriction (EIB). The main mechanism of EIB is considered to be airway dehydration, resulting from increased ventilation during exercise. In asthma, such water loss causes an increase in airway fluid osmolarity, inducing airway smooth muscle contraction following the release of mediators from airway inflammatory cells. Asthmatics frequently experience EIB, but it may also be observed in others not reporting asthma symptoms, particularly elite endurance athletes. Individuals with asthma often refrain from performing physical exercise because they fear troublesome respiratory symptoms. However, in addition to its well-known cardiovascular and metabolic benefits, physical training has been shown to be beneficial for asthmatic adults and children in improving asthma control and asthma-related quality of life. Exercise training also reduces the risk of asthma exacerbations, improves exercise capacity, and decreases frequency and severity of EIB. To minimize the risk of EIB, asthma must be well controlled, and specific pharmacological and nonpharmacological preventative measures can be taken. Counterintuitively, in high-level athletes, the development of asthma, airway hyperresponsiveness, and EIB can be promoted by intense training over many years following exposure to environmental conditions, such as cold air, pollutants, and allergens. As for nonathletes, athletes must have optimal asthma control and apply preventative measures against EIB, taking into account antidoping regulations for asthma medications. A better understanding of the impact of exercise on asthma should improve the overall care of asthmatic patients.

BMI predicts exercise induced bronchoconstriction in asthmatic boys.

Exercise induced bronchoconstriction (EIB) is a frustrating morbidity of asthma in children. Obesity has been associated with asthma and with more severe EIB in asthmatic children. To quantify the effect of BMI on the risk of the occurrence of EIB in children with asthma. Data were collected from six studies in which exercise challenge tests were performed according to international guidelines. We included 212 Children aged 7-18 years, with a pediatrician-diagnosed mild-to-moderate asthma. A total of 103 of 212 children (49%) had a positive exercise challenge (fall of FEV1 ≥ 13%). The severity of EIB, as measured by the maximum fall in FEV1 , was significantly greater in overweight and obese children compared to normal weight children (respectively 23.9% vs 17.9%; P = 0.045). Asthmatic children with a BMI z-score around +1 had a 2.9-fold higher risk of the prevalence of EIB compared to children with a BMI z-score around the mean (OR 2.9; 95%CI: 1.3-6.1; P < 0.01). An increase in BMI z-score of 0.1 in boys led to a 1.4-fold increased risk of EIB (OR 1.4; 95%CI: 1.0-1.9; P = 0.03). A reduction in pre-exercise FEV1 was associated with a higher risk of EIB (last quartile six times higher risk compared to highest quartile (OR 6.1 [95%CI 2.5-14.5]). The severity of EIB is significantly greater in children with overweight and obesity compared to non-overweight asthmatic children. Furthermore, this study shows that the BMI-z-score, even with a normal weight, is strongly associated with the incidence of EIB in asthmatic boys.

Exercise-Induced Bronchospasm and Allergy.

Sport is an essential part of childhood, with precious and acknowledged positive health effects but the impact of exercise-induced bronchoconstriction (EIB) significantly reduces participation in physical activity. It is important to recognize EIB, differentiating EIB with or without asthma if the transient narrowing of the airways after exercise is associated with asthmatic symptoms or not, in the way to select the most appropriate treatment among the many treatment options available today. Therapy is prescribed based on symptoms severity but diagnosis of EIB is established by changes in lung function provoked by exercise evaluating by direct and indirect tests. Sometimes, in younger children it is difficult to obtain the registration of difference between the preexercise forced expiratory volume in the first second (FEV1) value and the lowest FEV1 value recorded within 30 min after exercise, defined as the gold standard, but interrupter resistance, in association with spirometry, has been showed to be a valid alternative in preschool age. Atopy is the main risk factor, as demonstrated by epidemiologic data showing that among the estimated pediatric population with EIB up to 40% of them have allergic rhinitis and 30% of these patients may develop adult asthma, according with atopic march. Adopting the right treatment and prevention, selecting sports with no marked hyperventilation and excessive cooling of the airways, children with EIB can be able to take part in physical activity like all others.

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.

Aberrant small airways function relates to asthma severity in young children

BackgroundFrequency dependence of resistance (R5-20) assessed by impulse oscillometry (IOS) is suggested to be a measure of small airways. Small airways involvement during induced bronchoconstriction has been shown to reflect severity of asthma in adults. ObjectiveOur aim was to evaluate if methacholine (Mch) induced changes in R5-20 are associated with the severity of exercise induced bronchoconstriction (EIB) in young children. MethodsA total of 109 children aged 3–8 years were studied, 95 with obstructive symptoms and 14 in good health, to assess small airways function during a Mch challenge. R5-20 and other IOS resistance and reactance parameters were measured at baseline and after the Mch challenge. In a standardized exercise test, the children were grouped according to the severity of EIB expressed as the percentage increase in resistance at 5 Hz (ΔR5) after exercise, indicating either no EIB (ΔR5 < 40%, n = 84), moderate EIB (ΔR5 40–80%, n = 13) and severe EIB (ΔR5 > 80%, n = 12). ResultsThe baseline R5-20 was not associated with the severity of EIB, but during Mch induced bronchoconstriction the change in R5-20 was significantly higher in children with severe EIB (2.61 fold increase) than in children with moderate EIB (1.48) or no EIB (1.74, p = 0.036). No significant associations were found in changes of other IOS parameters. The children with severe EIB also used more short-acting beta-agonists during the past two months than the other two groups (p < 0.001). ConclusionFrequency dependence of resistance (R5-20) measured by IOS during the Mch induced bronchoconstriction and more frequent use of beta-agonists are associated with severe EIB in young children.

The association of forced expiratory volume in one second and forced expiratory flow at 50% of the vital capacity, peak expiratory flow parameters, and blood eosinophil counts in exercise-induced bronchospasm in children with mild asthma.

BackgroundExercise-induced bronchoconstriction (EIB), which describes acute airway narrowing that occurs as a result of exercise, is associated with eosinophilic airway inflammation, bronchial hyperresponsiveness. The forced expiratory volume in one second (FEV1) is the most commonly used spirometric test in the diagnosis of EIB in exercise challenge in asthma. Other parameters such as forced expiratory flow at 50% of the vital capacity (FEF50%) and peak expiratory flow (PEF) are used less often in the diagnosis of EIB.ObjectiveThe purpose of this study is to evaluate the association of FEV1 and FEF50%, PEF parameters, blood eosinophil counts in EIB in children with mild asthma.MethodsSixty-seven children (male: 39, female: 28) with mild asthma were included in this study. Pulmonary functions were assessed before and at 1, 5, 10, 15, and 20 minutes after exercise. The values of spirometric FEV1, FEF50%, PEF, and blood eosinophil counts were evaluated in EIB in children with mild asthma.ResultsThere was a positive correlation between FEV1 with FEF50% and PEF values (p<0.05; FEF50%, r=0.68; PEF, r=0.65). Also, a positive correlation was found between blood eosinophil counts and the values of spirometric FEV1, FEF50%, and PEF (p<0.05; FEV1, r=0.54; FEF50%, r=0.42; PEF, r=0.26). In addition to these correlations, in the exercise negative group for FEV1, the FEF50% and PEF values decreased more than the cutoff values in 3, and 2 patients, respectively.ConclusionAccording to the presented study, eosinophil may play a major role in the severity of EIB in mild asthma. FEF50% and PEF values can decrease in response to exercise without changes in FEV1 in mild asthmatic patients.

Exercise-Induced Bronchospasm In Adolescents: Characteristics Of Lung Function and Accuracy Of Symptoms

Exercise-induced bronchoconstriction (EIB) describes acute airway narrowing that occurs after exercises; although evidence-based documents exist to guide health care providers with regard to its diagnosis, it is often in medical practice considering only the symptoms, without a confirmatory test, to determine BIE. The aim of this study is to estimate the prevalence of EIB among adolescent students with and without reported asthma and to evaluate the accuracy of symptoms in detection of EIB. Cross-sectional study with 220 adolescents students from 12 to 14 years. A bronchial provocation exercise-induced test was performed and symptoms questionnaire for asthma and EIB was applied. Besides to estimate the prevalence of EIB and accuracy of symptoms to detect BIE, we compared the fall in FEV1 between asthmatics and non-asthmatics. The significance level was 95%. The prevalence of EIB was 19.1% (n = 42) (95% CI 14.0 to 24.0) and asthma was 18.6% (n= 41). Asthmatics with EIB showed significant decrease in FEV1 (p = 0.000) at 5 minutes post-exercise, showing increased earliness and severity of EIB when associated with asthma. Diagnosis of EIB by symptoms allocated 62 students. However, after bronchial provocation test, only 14 (22.6%) had a decrease > 10% in FEV1 (sensitivity 33%, specificity 73%, PPV: 22%, and NPV: 82%). There was synergism between EIB and asthma in reducing FEV1 post-test. Suggestive symptoms of EIB have low accuracy, with unacceptable false positives and negatives values for diagnosis. The clinical relevance is to discourage doctors in diagnosing EIB based only by symptoms.

Effects of dietary induced weight loss on exercise‐induced bronchoconstriction in overweight and obese children

Previous studies showed that obesity in asthmatic children is associated with more severe exercise-induced bronchoconstriction (EIB), compared with non-obese asthmatic children. This study investigates the effect of weight loss on EIB in overweight and obese asthmatic children. In this intervention study, children aged 8-18 years with EIB and moderate to severe overweight, followed a diet based on healthy daily intake for 6 weeks. Before and after the diet period they underwent an exercise challenge test in cold air. Primary outcome was change in exercise-induced fall in FEV1 and relation between weight loss and EIB. Secondary outcomes were changes in recovery of FEV1 ("area under the curve"; AUC), fraction of exhaled nitric oxide (FeNO) and scores of the Pediatric Asthma Quality of Life Questionnaire (PAQLQ) and Asthma Control Questionnaire (ACQ). Twenty children completed the study. After the diet period, weight, and body mass index (BMI) were significantly reduced (changes respectively -2.6% and -1.5 kg/m(2), P < 0.01). There was a significant improvement of the percentage exercise-induced fall in FEV1 (30.6% vs. 21.8%, P < 0.01), AUC and PAQLQ score. The reduction in BMI z-score was significantly related to the reduction in the percentage exercise-induced fall in FEV1 in children that lost weight (r = 0.53, P = 0.03). There were no changes in FeNO and ACQ. Dietary induced weight loss in overweight and obese asthmatic children leads to significant reduction in severity of EIB and improvement of the quality of life. The reduction in BMI z-score is significantly related to the improvement of EIB.

Role of leukotrienes in exercise-induced bronchoconstriction before and after a pilot rehabilitation training program

BackgroundWhatever the initial stimulus for the exercise-induced bronchoconstriction (EIB) observed in asthmatic patients after exercise, the final effect is release of bronchoactive mediators, especially cysteinyl leukotrienes. Exercise rehabilitation training programs have been reported to protect against EIB. The exact mechanism(s) involved are not well understood. However, this protective effect may be related to adaptation and better coordination during exercise, depletion of cysteinyl leukotrienes, and/or a sluggish cysteinyl leukotriene response to exercise. The aim of the present work was to test the hypothesis that improvement in the incidence and severity of post-exercise bronchoconstriction after a rehabilitation training program is related to a change in leukotriene levels in response to exercise.MethodsTwenty asthmatic children aged 6–12 years and known to develop EIB were enrolled in an exercise training program for 12 weeks. The severity and incidence of EIB before and after training was assessed. Baseline and post-exercise sputum cysteinyl leukotriene levels were assessed before and after the training program.ResultsThe training program offered significant protection against EIB with a concomitant decrease in sputum cysteinyl leukotriene levels in response to exercise.ConclusionA training program can result in depletion and/or a sluggish cysteinyl leukotriene response to exercise and may be responsible for the protective effect of training programs on EIB. It is recommended to use an exercise rehabilitation training program as a complementary tool in the management of bronchial asthma, especially EIB.

Bronchial and alveolar nitric oxide in exercise‐induced bronchoconstriction in asthmatic children

Epidemiological studies have shown an association between the severity of exercise-induced bronchoconstriction (EIB) and fractional exhaled nitric oxide at the flow of 50 mL/s (FeNO(50)). However, no study has assessed the correlation between alveolar production (C(alv)) and bronchial flux (J(NO)) of nitric oxide (NO) and EIB in asthmatic children. To identify the relationship between severity of EIB and bronchial or alveolar nitric oxide. Our group included 36 allergic children with intermittent asthma. The EIB was determined by a standard exercise challenge and the severity was expressed as the maximum change in percentage from the baseline value of lung function (ΔFEV(1)%, ΔFEF(25-75)%) after exercising. A chemiluminescence analyser at multiple flows was used to calculate FeNO(50), J(NO) and C(alv,) which reflect large airways, J(NO) and alveolar concentration of NO respectively. Sixteen (44.4%) children presented a ∆FEV(1) ≥ 10%, eight (22.2%) had ∆FEV(1) ≥ 15% and nine (25%) children had a ∆FEF(25-75) ≥ 26%. A significant correlation was observed between severity of EIB and FeNO(50) , J(NO) and C(alv.) EIB was significantly more severe in children sensitive to indoor allergens compared with outdoor allergens only (P = 0.014); those children showed also higher levels of C(alv) (P = 0.003) and of J(NO) (P = 0.044). Our results suggest that inflammation is present in the central and peripheral airways and that it is associated with the severity of EIB. Clinicaltrials.gov NCT00952835.

Exercise-Induced Bronchoconstriction in Children and Adolescents

Exercise-induced bronchoconstriction (EIB) is common in children. This article reviews the epidemiology, clinical presentation, pathophysiology, diagnosis, and treatment of EIB. EIB is caused by transient narrowing of the airways during or most often after exercise and indicates airway hyperresponsiveness. EIB is an important cause of exercise limitation in children. However, the diagnosis of EIB can be challenging because symptoms poorly predict the presence of EIB. Bronchial challenges, such as cardiopulmonary exercise testing, are required to document EIB. The severity of EIB is worsened by exposure to inhalational toxicants such as chlorine in pools and air pollution. In most children, EIB can be effectively prevented by both nonpharmacological means and medications. Educating the child, his/her family, and supervising adults about asthma triggers and management is important. Prompt recognition and treatment of an asthma attack associated with exercise is critical; bronchodilators should be on the sidelines at all times, and an asthma action plan should be in place.

Serum leptin and adiponectin levels correlate with exercise-induced bronchoconstriction in children with asthma

Exercise-induced bronchoconstriction (EIB), a form of bronchial hyperresponsiveness (BHR), is common in children with asthma or obesity. Epidemiological studies have shown that asthma and obesity are increasing in parallel, but obesity- and adipokine-related effects on inflammation and BHR have not yet been demonstrated in the human airway. To address the relationship between leptin and adiponectin and EIB in children with asthma. Eighty-five prepubertal children between the ages of 6 and 10 years were included in our study. They comprised obese with asthma (n = 19), normal weight with asthma (n = 23), obese without asthma (n = 23), and healthy (n = 20). We measured serum leptin and adiponectin levels. We also performed pulmonary function tests: baseline, postbronchodilator inhalation, methacholine inhalation, and exercise. The area under the forced expiratory volume in 1 second (FEV(1))-time curve quantified the severity of EIB over a 20-minute period after exercise (AUC(20)). The obese children had significantly elevated levels of leptin and reduced levels of adiponectin. The maximum decreases in %FEV(1) and AUC(20) after exercise were positively correlated with leptin levels and negatively with serum adiponectin levels in children with asthma. The odds for having EIB were incrementally and significantly higher for children with higher levels of serum leptin. Levels of the adipocyte-derived hormones leptin and adiponectin are significantly correlated with BHR induced by exercise challenge in children with asthma. Further studies are needed to elucidate whether the changes in leptin and adiponectin levels bear a causal relationship to the EIB/BHR.

Conjugated Linoleic Acid’s Lack of Attenuation of Hyperpnea-Induced Bronchoconstriction in Asthmatic Individuals in the Short Term

Conjugated linoleic acid (CLA) has been reported to modify the inflammatory response associated with allergic airway disease, primarily in animal models. To extend these observations to humans, the effect of short-term CLA supplementation on the severity of exercise-induced bronchoconstriction (EIB) was investigated in asthmatics. Six subjects with physician-diagnosed asthma and EIB began the study on their usual diet, to which was added 4.8 g CLA/d for 8 wk. Pulmonary-function tests were administered before and after eucapnic voluntary hyperventilation (EVH) challenge at the commencement (Week 0) and conclusion of the treatment period (Week 8). Pre- and 90 min post-EVH challenge, urine was assayed for the presence of cysteinyl leukotrienes (LT) C4-E4 and 9α, 11β-prostaglandin (PG) F2. Pre- to post-EVH forced expiratory volume in 1 s (FEV1) did not significantly differ (p > .05) from Week 8 to Week 0. The pre- to post-EVH decline in FEV1 at Week 8 (-29.6% ± 6.6%) was not significantly different (p > .05) from that at Week 0 (-32.0% ± 5.5%). Area under the curve of FEV1 plotted against time from zero to 60 min (AUC0-60) was unaltered at Week 8 (-931% ± 350% change per minute) compared with Week 0 (-1,090% ± 270% change per minute). CLA supplementation did not alter forced midexpiratory flow, forced vital capacity (FVC), or FEV1/FVC. In addition, post-EVH urinary LTC4-E4 and 9α, 11β-PGF2 were unchanged after CLA supplementation. Daily supplementation of 4.8 g CLA for 8 wk does not attenuate airway inflammation or hyperpnea-induced bronchoconstriction in asthmatic individuals.