Exercise-induced Bronchoconstriction In Subjects Research Articles

Predictors of exercise-induced bronchoconstriction in subjects with mild asthma

BackgroundPhysical effort is capable of triggering airway obstruction in asthmatics, the so-called exercise-induced bronchoconstriction in asthma (EIBa). This study was performed in subjects with mild persistent asthma, aiming to find predictors for developing EIBa.MethodsIn 20 subjects with mild asthma, measurements of baseline functional respiratory parameters and airways responsiveness by a methacholine challenge were obtained on the first day. A maximal, symptom-limited incremental cardiopulmonary exercise test (CPExT) was performed the day after, with subsequent, repeated maneuvers of maximal full forced expiration to monitor the FEV1 change at 1,3,5,7,10 and 15 min after the end of the exercise.Results19 subjects completed the two-days protocol. No functional parameters both at rest and during effort were useful to predict EIBa after stopping exercise. In asthmatics with EIBa, mean Inspiratory Capacity (IC) did not increase with increasing ventilatory requirements during CPExT because 6 of them (50%) displayed dynamic pulmonary hyperinflation (DH), as documented by their progressive increase of end-expiratory lung volume. This subgroup, showing earlier post-exercise FEV1 fall, had significantly lower forced mean expiratory flow between 25% and 75% of forced vital capacity (FEF25-75%) at rest (p < 0.05) and higher airways responsiveness, expressed as PD20FEV1 (p < 0.05) as compared with other asthmatics with EIBa.ConclusionsNo functional respiratory parameters seem to predict EIBa in mild asthmatics. However, in those with EIBa, a subgroup developed DH during exercise, and this was associated with a baseline reduced forced expiratory flow rates at lower lung volumes and higher airway hyperresponsiveness, suggesting a prominent small airways impairment.

Exercise in Sub-zero Temperatures and Airway Health: Implications for Athletes With Special Focus on Heat-and-Moisture-Exchanging Breathing Devices.

Asthma is highly prevalent among winter endurance athletes. This “occupational disease” of cross-country skiers, among others, was acknowledged during the 1990s, with the pathogenesis attributed to repeated and prolonged exposure to cold, dry air combined with high rates of ventilation during exercise. Nevertheless, more than 25 years later, the prevalence of asthma among Scandinavian cross-country skiers is unchanged, and prevention remains a primary concern for sports physicians. Heat-and-moisture-exchanging breathing devices (HMEs) prevent exercise-induced bronchoconstriction in subjects with pre-existing disease and may have potential as a preventative intervention for healthy athletes undertaking training and competition in winter endurance sports. Herein we firstly provide an overview of the influence of temperature and humidity on airway health and the implications for athletes training and competing in sub-zero temperatures. We thereafter describe the properties and effects of HMEs, identify gaps in current understanding, and suggest avenues for future research.

Exercise-induced Bronchoconstriction with Firefighting Contained Breathing Apparatus.

Protective self-contained breathing apparatus (SCBA) used for firefighting delivers decompressed (cold) dehumidified air that may enhance the severity of exercise-induced bronchoconstriction (EIB) in those susceptible. We investigated the effect of SCBA during exercise on airway caliber in people with asthma and healthy controls. Two exercise challenges (EC) designed to elicit EIB were performed on separate days within 1 wk. The initial challenge was breathing room air (ECRA) with workload titrated to elicit >60% estimated maximum voluntary ventilation. The exercise intensity was repeated for the second challenge using SCBA (ECSCBA). Forced expiratory volume in 1 s (FEV1) was measured before and up to 20 min after exercise. Bronchial hyperresponsivenss (BHR) to the hyperosmolar mannitol test was measured in the subjects with asthma. Twenty subjects with current asthma (mean [SD]: age 27 [6] yr) and 10 healthy controls (31 [5] yr, P = 0.1) were studied. The percent fall in FEV1 after ECSCBA was greater in the mannitol-positive asthma subjects (14.4% [15.1%]) compared with mannitol-negative asthmatic subjects (1.6% [1.7%]; P = 0.02) and controls (2.3% [2.3%]; P = 0.04). The FEV1 response was not different between ECRA and ECSCBA (0.49% [5.57%]; P = 0.6). No BHR to mannitol (n = 7) was highly sensitive for identifying a negative response to ECSCBA (negative predictive value 100%). The SCBA does not increase the propensity or severity for EIB in subjects with BHR. Those subjects with asthma but no BHR to inhaled mannitol did not exhibit EIB. The BHR to a hyperosmolar stimulus maybe considered a useful screening tool for potential recruits with a history of asthma.

The effect of GSK2190915, a 5-lipoxygenase‐activating protein inhibitor, on exercise-induced bronchoconstriction

Exercise-induced bronchoconstriction (EIB) describes the condition whereby exercise causes airflow obstruction that lasts for up to 90 minutes without treatment. This double-blind, placebo-controlled, five-way crossover study investigated the dose response and duration of action of a 5-lipoxygenase-activating protein inhibitor, GSK2190915, to inhibit EIB in subjects with asthma. Forty-seven subjects with EIB were enrolled. Exercise challenge testing was scheduled at 2, 9.5, and 24 hours after receiving a single dose of GSK2190915 (10, 50, 100, and 200 mg) or placebo in randomized order. GSK2190915 at 200 and 100 mg significantly attenuated the response to exercise at 2 and 9.5 hours postdose, respectively, compared with placebo. The adjusted mean maximum percentage change from baseline forced expiratory volume at 1 second within 60 minutes postexercise challenge (FEV1 (0-60)) treatment difference for GSK2190915 at 200 mg compared with placebo at 2 hours postdose was 6.30% (95% CI, 3.06, 9.54), corresponding to a 40% attenuation of the placebo response to exercise; the treatment difference between GSK2190915 at 100 mg and placebo at 9.5 hours postdose was 3.49% (95% CI, 1.02, 5.95), corresponding to a 41% attenuation of the placebo response to exercise. No significant effect was seen at 24 hours postdose with any dose; however, investigation of statistically significant treatment-related effects at this time point was limited because of the small fall in adjusted mean FEV1 (0-60) (-7.61%; 95% CI, -10.23, -4.99) after placebo. GSK2190915 may be of benefit in EIB prevention. GSK Clinical Study LPA112025; ClinicalTrials.gov identifier number: NCT00812929.

Sputum Eosinophils and the Response of Exercise-Induced Bronchoconstriction to Corticosteroid in Asthma

The relationship between eosinophilic airway inflammation and exercise-induced bronchoconstriction (EIB), and the response to inhaled corticosteroid (ICS) therapy was examined. Twenty-six steroid-naïve asthmatic patients with EIB were randomized to two parallel, double-blind, crossover study arms (13 subjects in each arm). Each arm compared two dose levels of inhaled ciclesonide that were administered for 3 weeks with a washout period of 3 to 8 weeks, as follows: (1) 40 vs 160 microg daily; and (2) 80 vs 320 microg daily. Baseline and weekly assessments with exercise challenge and sputum analysis were performed. Data were pooled and demonstrated that 10 subjects had baseline sputum eosinophilia >or= 5%. Only high-dose ICS therapy (ie, 160 and 320 microg) significantly attenuated the sputum eosinophil percentage. Sputum eosinophil percentage significantly correlated with EIB severity, and predicted the magnitude and temporal response of EIB to high-dose therapy, but not to low-dose therapy (ie, 40 and 80 microg). Low-dose ICS therapy provided a significant reduction in EIB at 1 week, with little additional improvement thereafter, irrespective of baseline sputum eosinophil counts. In contrast, high-dose ICS therapy provided a significantly greater improvement in EIB in subjects with sputum eosinophilia compared to those with an eosinophil count of < 5%. The difference between the eosinophilic groups in the magnitude of improvement in EIB was evident after the first week of high-dose ICS therapy and increased with time. These results suggest that eosinophilic airway inflammation may be important in modifying the severity of EIB and the response to ICS therapy. Measurements of sputum eosinophil percentage may, therefore, be useful in predicting the magnitude and temporal response of EIB to different dose levels of ICSs. clinicaltrial.gov; Identifier: NCT00525772.

Exercise capacity and exercise-induced bronchoconstriction (EIB) in a cold environment

Exercise in a cold environment has been reported to increase exercise-induced bronchoconstriction (EIB). However, the effect of a cold environment upon exercise capacity in subjects with EIB has, to our knowledge, not been previously reported. Primary: To examine the influence of changing environmental temperature upon exercise capacity measured by peak oxygen uptake (VO(2 peak)), peak ventilation (VE(peak)) and peak running speed in subjects with diagnosed EIB. Secondary: To assess the influence of changing environmental temperature upon EIB. Twenty subjects (10-45 years old, male/female: 13/7) with EIB underwent exercise testing by running on a treadmill in a climate chamber under standardised, regular conditions, 20.2 degrees C (+/-1.1) and 40.0% (+/-3.3) relative humidity [mean(+/-SD)], and in a standardised cold environment, -18.0 degrees C (+/-1.4) and 39.2% (+/-3.8) relative humidity in random order on separate days. Oxygen uptake (VO(2)), minute ventilation (V E), respiratory exchange ratio (RER), heart rate (HR) and running speed were measured during exercise. Lung function (flow volume loops) was measured before and 1, 3, 6, 10 and 15 min after exercise and 15 min after inhalation of salbutamol. VO(2 peak) decreased 6.5%, from 47.9 (45.0, 50.8) to 44.8 ml kg(-1)min(-1) (41.2, 48.4) [mean (95% confidence intervals)] (p=0.004) in the cold environment. Also running speed was significantly lower in the cold environment (p=0.02). No differences were found for VE(peak), RER(peak) or HR(peak). The post-exercise reduction in forced expiratory volume in 1s (FEV(1)) (DeltaFEV(1)) increased significantly from 24% (19,29) to 31% (24,38), respectively (p=0.04) after exercise in the cold environment. No correlation was found between reduction in VO(2 peak) and the increased maximum fall in FEV(1) in the cold environment. Exercise capacity (VO(2 peak) and peak running speed) was markedly reduced during exercise in a cold environment whereas EIB increased in subjects suffering from EIB.

Protective Effect of Fish Oil Supplementation on Exercise-Induced Bronchoconstriction in Asthmatic Subjects

PURPOSE: Previous research has demonstrated that fish oil supplementation has a protective effect on exercise-induced bronchoconstriction (EIB) in elite athletes, which may be attributed to its antiinflammatory properties. Since EIB in asthma involves pro inflammatory mediator release, it is feasible that fish oil supplementation may reduce the severity of EIB in asthmatic subjects. The main aim of the study was to determine the efficacy offish oil supplementation on severity of EIB in subjects with asthma. METHODS: Sixteen asthmatic patients with documented EIB participated in a randomized, double-blind crossover study. Subjects entered the study on their normal diet, and then received either fish oil capsules containing 3.2 g eicosapentaenoic acid 2.0 g docohexaenoic acid (fish oil diet; n=8) or placebo capsules (placebo diet; n=8) taken daily for 3 weeks. At the beginning of the study (normal diet) and at the end of each treatment phase the following pre- and post-exercise measures were assessed: (1) pulmonary function; (2) induced sputum (IS) differential cell count percentage and pro inflammatory eicosanoid metabolite (LTC4-E4 and PGD2) and cytokine (IL-1β and TNF-α) concentrations; (3) eicosanoid metabolites LTB4 and LTB5 generation from activated polymorp ho nuclear leukocytes (PMNLs). RESULTS: On the normal and placebo diet subjects exhibited EIB. However, the fish oil diet improved pulmonary function to below the diagnostic EIB threshold, with a concurrent reduction in broncho dilator use. IS differential cell count percentage and concentration of LTC4-E4, PGD2, IL-1β and TNF-α were significantly reduced before and following exercise on the fish oil diet compared to the normal and placebo diet. There was a significant reduction in LTB4 and a significant increase in LTB5 generation from activated PMNLs on the fish oil diet compared to the normal and placebo diet. CONCLUSIONS: Our data suggest that fish oil supplementation may represent a potentially beneficial nonpharmacological intervention for asthmatic subjects with EIB.

Protective Effect of Fish Oil Supplementation on Exercise-Induced Bronchoconstriction in Asthma

Previous research has demonstrated that fish oil supplementation has a protective effect on exercise-induced bronchoconstriction (EIB) in elite athletes, which may be attributed to its antiinflammatory properties. Since EIB in asthma involves proinflammatory mediator release, it is feasible that fish oil supplementation may reduce the severity of EIB in asthmatic subjects. To determine the efficacy of fish oil supplementation on severity of EIB in subjects with asthma. Randomized, double-blind, crossover study. Lung function and exercise testing in a university research laboratory. Sixteen asthmatic patients with documented EIB entered the study on their normal diet and then received either fish oil capsules containing 3.2 g of eicosapentaenoic acid and 2.0 g of docohexaenoic acid (fish oil diet, n = 8) or placebo capsules (placebo diet, n = 8) daily for 3 weeks. At the beginning of the study (normal diet) and at the end of each treatment phase, the following pre-exercise and postexercise measures were assessed: (1) pulmonary function; (2) induced sputum differential cell count percentage and proinflammatory eicosanoid metabolite (leukotriene C4 [LTC4]-leukotriene E4 [LTE4] and prostaglandin D2 [PGD2]) and cytokine (interleukin [IL]-1beta and tumor necrosis factor [TNF]-alpha) concentrations; and (3) eicosanoid metabolites leukotriene B4 (LTB4) and leukotriene B5 (LTB(5)) generation from activated polymorphonuclear leukocytes (PMNLs). On the normal and placebo diet, subjects exhibited EIB. However, the fish oil diet improved pulmonary function to below the diagnostic EIB threshold, with a concurrent reduction in bronchodilator use. Induced sputum differential cell count percentage and concentrations of LTC4-LTE4, PGD2, IL-1beta, and TNF-alpha were significantly reduced before and following exercise on the fish oil diet compared to the normal and placebo diets. There was a significant reduction in LTB4 and a significant increase in LTB5 generation from activated PMNLs on the fish oil diet compared to the normal and placebo diets. Our data suggest that fish oil supplementation may represent a potentially beneficial nonpharmacologic intervention for asthmatic subjects with EIB.

Asthma in medium altitude – exercise‐induced bronchoconstriction in hypobaric environment in subjects with asthma

Hypoxic gas inhalation has been reported to enhance airway responsiveness and results in bronchoconstriction in animal models and in humans with asthma. However, the data have so far been conflicting. The aim of the present study was to examine the effect of reduced barometric pressure on exercise-induced bronchoconstriction (EIB) in subjects with asthma. Twenty subjects (10-45 years old, male symbol/female symbol = 13/7) with asthma (at least 10% reduction in forced expiratory volume in 1-second postexercise) participated in exercise testing in barometric pressure corresponding to altitudes of 200 (normobaric) and 2500 (hypobaric) m above sea level in random order on separate days. Lung function was measured before and after exercise, as well as after inhalation of salbutamol. Heart rate, oxygen uptake (), arterial oxygen saturation (S(p)O(2)), respiratory gas exchange ratio (RER) and minute ventilation () were measured during exercise. There was no difference in lung function after exercise. The and HR(peak) during exercise did not differ. The RER(peak) was higher (P = 0.04) in hypobaric environment. The decreased 10.1% (7.2-13.0) [mean (95% confidence intervals)] (P < 0.001) from normobaric to hypobaric environment. At the same time, S(p)O(2) at decreased from 94.4 (92.2-96.6) to 85.6% (82.8-88.4) (P < 0.001). A barometric pressure corresponding to altitude of 2500 m did not increase EIB in subjects with asthma. The reduction in is most probably due to the lower S(p)O(2) in hypobaric environment.

Effects of oral cetirizine, a selective H 1 antagonist, on allergen- and exercise-induced bronchoconstriction in subjects with asthma

The protective efficacy of oral cetirizine, a selective and potent H 1-receptor antagonist, against the immediate bronchoconstrictive response to allergen inhalation and exercise challenge was evaluated in 16 subjects with stable, predominantly mild asthma. The subjects underwent double-blind, crossover pretreatments in randomized order in two separate protocols with (1) three daily oral doses of 20 mg of cetirizine and placebo, followed by allergen inhalation, and (2) single oral doses of cetirizine (5, 10, and 20 mg), albuterol (4 mg), and placebo, followed by exercise with cold-air inhalation. Cetirizine failed to decrease bronchial sensitivity to inhaled allergen in eight of 10 subjects. Neither cetirizine nor albuterol uniformly inhibited exercise-induced bronchoconstriction. Serum concentrations of cetirizine were consistent with systemic H 1-blocking activity. Modest bronchodilation occurred after administration of cetirizine and albuterol before exercise but not after the third dose of cetirizine in the allergen protocol. One subject developed moderate drowsiness during multiple dosing with cetirizine. Thus, cetirizine, in the doses studied, is not uniformly effective in preventing allergen- or exercise-induced bronchoconstriction. Histamine is one of many mediators participating in immediate asthmatic responses, and selective H 1 antagonists do not completely block these airway events. However, cetirizine may still clinically benefit some patients with asthma, such as patients with allergic rhinitis or urticaria.