Oil supplementation with a special combination of n-3 and n-6 long-chain polyunsaturated fatty acids does not protect for exercise induced asthma: a double-blind placebo-controlled trial.

BACKGROUND: Many patients suffering from exercise-induced asthma (EIA) have normal lung function at rest and show symptoms and a decline in FEV1 when they do sports or during exercise-challenge. It has been described that long-chain polyunsaturated fatty acids (LCPUFA) could exert a protective effect on EIA. METHODS: In this study the protective effect of supplementation with a special combination of n-3 and n-6 LCPUFA (sc-LCPUFA) (total 1.19 g/ day) were investigated in an EIA cold air provocation model. PRIMARY OUTCOME MEASURE: Decrease in FEV1 after exercise challenge and secondary outcome measure: anti-inflammatory effects monitored by exhaled NO (eNO) before and after sc-LCPUFA supplementation versus placebo. RESULTS: Ninety-nine patients with exercise-induced symptoms aged 10 to 45 were screened by a standardized exercise challenge in a cold air chamber at 4 °C. Seventy-three patients fulfilled the inclusion criteria of a FEV1 decrease > 15% and were treated double-blind placebo-controlled for 4 weeks either with sc-LCPUFA or placebo. Thirty-two patients in each group completed the study. Mean FEV1 decrease after cold air exercise challenge and eNO were unchanged after 4 weeks sc-LCPUFA supplementation. CONCLUSION: Supplementation with sc-LCPUFA at a dose of 1.19 g/d did not have any broncho-protective and anti-inflammatory effects on EIA. TRIAL REGISTRATION: Clinical trial registration number: NCT02410096. Registered 7 February 2015 at Clinicaltrial.gov.

Noninvasive ventilation and respiratory physical therapy reduce exercise-induced bronchospasm and pulmonary inflammation in children with asthma: randomized clinical trial.

BACKGROUND: Asthma is characterized by hyperresponsiveness of the airways, and exercise-induced bronchospasm (EIB) is a symptom that limits a large proportion of asthmatic patients, especially children. Continuous positive airway pressure (CPAP) leads to a reduction in the reactivity of the airways. The aim of this study was to evaluate the effect of outpatient treatment with CPAP and bilevel pressure combined with respiratory physical therapy for children and adolescents with asthma following bronchial hyperresponsiveness caused by an exercise bronchoprovocation test. METHODS: A randomized, controlled, blind, clinical trial was conducted involving 68 asthmatic children and adolescents aged 4 to 16 years divided into three groups: G1, treated with bilevel pressure (inspiratory positive airway pressure: 12 cm H2O; expiratory positive airway pressure: 8 cm H2O), G2, treated with CPAP (8 cm H2O) and G3, treated with respiratory muscle training (RMT), considered as the control group. All groups were treated at an outpatient clinic and submitted to 10 1-hour sessions, each of which also included respiratory exercises. Evaluations were performed before and after treatment and involved spirometry, an exercise bronchoprovocation test, respiratory pressures, fraction of nitric oxide (FeNO), the Asthma Control Questionnaire (ACQ6) and anthropometric variables. This study received approval from the local ethics committee (certificate number: 1487225/2016) and is registered with ClinicalTrials [ ClinicalTrials.gov identifier: NCT02939625]. RESULTS: A total of 64 patients concluded the protocol; the mean age of the patients was 10 years. All were in the ideal weight range and had adequate height ( z score: -2 to +2). The three groups demonstrated improved asthma control after the treatments, going from partial to complete control. A significant increase in maximal inspiratory pressure occurred in the three groups, with the greatest increase in the RMT group. A reduction in FeNO in the order of 17.4 parts per billion (effect size: 2.43) and a reduction in bronchial responsiveness on the exercise bronchoprovocation test occurred in the bilevel group. An improvement in FeNO on the order of 15.7 parts per billion (effect size: 2.46) and a reduction in bronchial responsiveness occurred in the CPAP group. No changes in lung function or responsiveness occurred in the RMT group. CONCLUSION: Positive pressure and respiratory exercises were effective in reducing pulmonary inflammation, exercise-innduced bronchoespasm (EIB), and increased the clinical control of asthma, as well as RMT, which also resulted in improved clinical control.

Nonpharmacologic Strategies to Manage Exercise-Induced Bronchoconstriction.

Pharmacologic management of exercise-induced bronchoconstriction (EIB) is the mainstay of preventative therapy. There are some nonpharmacologic interventions, however, that may assist the management of EIB. This review discusses these nonpharmacologic interventions and how they may be applied to patients and athletes with EIB.

Eucapnic voluntary hyperventilation test in children.

BACKGROUND: 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. PURPOSE: The purpose of the "pilot study" was to study the usability of the EVH test with real time biofeedback in children of 10-16 years of age in the diagnostics of exercise-induced dyspnea. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

Fenotipos del asma, ¿son importantes? / Asthma Phenotypes; Do They Matter?

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The effect of climatic conditions on exercise-induced bronchoconstriction in 10-12 year old students.

Exercise-induced asthma is seen following vigorous or prolonged exercise or physical exertion. It has been suggested that climatic conditions have an influence on exercise-induced asthma. Therefore, the aim of the present study was to examine the effect of two climatic conditions on exercise-induced deterioration of pulmonary function tests in 10-12 year old students. Two hundred and fifty six students were randomly chosen from two cities namely Kerman and Gorgan (128 subjects in each who were equally from both cities) including 62 girls and 66 boys of 10-12 years old. A questionnaire was used to obtain demographic information and to identify the prevalence of asthma symptoms. Each subject performed a seven-minute free run exercise with maximum effort and sufficient motivation until they reached 70-75% heart rate. Pulmonary function tests (PFT) including, forced vital capacity (FVC), forced expiratory volume in one second (FEV1), peak expiratory flow (PEF), and maximum expiratory flow at 50% of vital capacity (MEF50) were measured before, at the beginning, and 7 and 20 min after physical activity. The prevalence of both asthma (28.12%) and exercise-induced asthma (20.31%) in Kerman students was higher than those of Gorgan students (21.09% and 17%, respectively). All PFT values declined 7 and 20 min post-exercise in both groups. Although all baselines PFT in Kerman students were higher than those of Gorgan students, the decline in PFT values in Kerman students was greater than those of Gorgan students. At 20 min post exercise, the decline in FEV1, PEF and MEF50 in Kerman students was significantly higher than those of Gorgan students (p < 0.05 to p < 0.01). The results of the present study showed that prevalence of both asthma and exercise-induced asthma in a city with dry and cool climate such as Kerman was higher than in a city with humid climate such as Gorgan. In addition, the results showed that in a humid climate, post-exercise decline in PFT values was less than in a dry climate.

Exercise-induced bronchoconstriction update-2016.

The first practice parameter on exercise-induced bronchoconstriction (EIB) was published in 2010. This updated practice parameter was prepared 5 years later. In the ensuing years, there has been increased understanding of the pathogenesis of EIB and improved diagnosis of this disorder by using objective testing. At the time of this publication, observations included the following: dry powder mannitol for inhalation as a bronchial provocation test is FDA approved however not currently available in the United States; if baseline pulmonary function test results are normal to near normal (before and after bronchodilator) in a person with suspected EIB, then further testing should be performed by using standardized exercise challenge or eucapnic voluntary hyperpnea (EVH); and the efficacy of nonpharmaceutical interventions (omega-3 fatty acids) has been challenged. The workgroup preparing this practice parameter updated contemporary practice guidelines based on a current systematic literature review. The group obtained supplementary literature and consensus expert opinions when the published literature was insufficient. A search of the medical literature on PubMed was conducted, and search terms included pathogenesis, diagnosis, differential diagnosis, and therapy (both pharmaceutical and nonpharmaceutical) of exercise-induced bronchoconstriction or exercise-induced asthma (which is no longer a preferred term); asthma; and exercise and asthma. References assessed as relevant to the topic were evaluated to search for additional relevant references. Published clinical studies were appraised by category of evidence and used to document the strength of the recommendation. The parameter was then evaluated by Joint Task Force reviewers and then by reviewers assigned by the parent organizations, as well as the general membership. Based on this process, the parameter can be characterized as an evidence- and consensus-based document.

Improved lung function following dietary antioxidant supplementation in exercise-induced asthmatics.

INTRODUCTION: Oxidative stress is a characteristic of exercise-induced asthma (EIA), however antioxidant supplementation may attenuate EIA. The purpose of this study was to determine if ascorbic (AsA) and α-tocopherol supplementation would improve airway function in subjects with EIA. METHODS: A single-blind randomized crossover design with eight clinically diagnosed EIA subjects (22.0 ± 0.7 year) and five healthy control subjects (28.2 ± 1.4 year) was used. Subjects consumed vitamins (V) (AsA 500 mg; α-tocopherol 300 IU) or placebo (PLA) daily for three weeks, followed by a three week washout period and then three weeks of the alternative treatment. Ten-minute treadmill tests (90% VO2peak) were performed with pulmonary function testing (forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and between 25 and 75% (FEF25-75%), and peak expiratory flow rates (PEFR)) measured pre-exercise and 1, 5, 15, and 30 min post-exercise. RESULTS: Supplementation led to significant improvements at minute 5 and minute 15 in FVC; FEV1; PERF; FEF25-75% and minute 30 in FEV1 and FEF25-75% post-exercise. CONCLUSION: AsA and α-tocopherol may aid the recovery of pulmonary function in subjects with EIA.

Respiratory inflammation and infections in high-performance athletes.

Upper respiratory illness is the most common reason for non-injury-related presentation to a sports medicine clinic, accounting for 35-65% of illness presentations. Recurrent or persistent respiratory illness can have a negative impact on health and performance of athletes undertaking high levels of strenuous exercise. The cause of upper respiratory symptoms (URS) in athletes can be uncertain but the majority of cases are related to common respiratory viruses, viral reactivation, allergic responses to aeroallergens and exercise-related trauma to the integrity of respiratory epithelial membranes. Bacterial respiratory infections are uncommon in athletes. Undiagnosed or inappropriately treated asthma and/or allergy are common findings in clinical assessments of elite athletes experiencing recurrent URS. High-performance athletes with recurrent episodes of URS should undergo a thorough clinical assessment to exclude underlying treatable conditions of respiratory inflammation. Identifying athletes at risk of recurrent URS is important in order to prescribe preventative clinical, training and lifestyle strategies. Monitoring secretion rates and falling concentrations of salivary IgA can identify athletes at risk of URS. Therapeutic interventions are limited by the uncertainty of the underlying cause of inflammation. Topical anti-inflammatory sprays can be beneficial for some athletes. Dietary supplementation with bovine colostrum, probiotics and selected antioxidants can reduce the incidence or severity of URS in some athletes. Preliminary studies on athletes prone to URS indicate a genetic predisposition to a pro-inflammatory response and a dysregulated anti-inflammatory cytokine response to intense exercise as a possible mechanism of respiratory inflammation. This review focuses on respiratory infections and inflammation in elite/professional athletes.

Vitamin D and omega-3 polyunsaturated fatty acid supplementation in athletes with exercise-induced bronchoconstriction: a pilot study.

OBJECTIVE: The aim of this pilot study was to determine the combined effect of vitamin D and omega-3 polyunsaturated fatty acid (PUFA) supplementation on airway function and inflammation in recreational athletes with exercise-induced bronchoconstriction (EIB). METHODS: Ten recreational athletes with EIB participated in a single-blind, placebo-controlled trial over six consecutive weeks. All subjects attended the laboratory on three occasions. Each visit was separated by a period of 3 weeks: visit 1 (usual diet), visit 2 (placebo) and visit 3 (SMARTFISH® NutriFriend 2000; 30 µg vitamin D3-3000 mg eicosapentaenoic acid, 3000 mg docosahexaenoic acid) consumed once daily for a period of 3 weeks. Venous blood was collected at the beginning of each trial to determine vitamin D status. Spirometry was performed pre- and post-eucapnic voluntary hyperpnoea (EVH). RESULTS: The Maximum fall in FEV1 (ΔFEV1max) post-EVH was not different between visits (usual diet: -15.9 ± 3.6%, placebo: -16.1 ± 6.1%, vitamin D + omega-3 PUFA: -17.8 ± 7.2%). Serum vitamin D remained unchanged between visits. CONCLUSION: Vitamin D and omega-3 PUFA supplementation does not attenuate the reduction in lung function post-EVH. This finding should be viewed as preliminary until the results of randomised controlled trials are made available.

Larynx during exercise: the unexplored bottleneck of the airways.

Exercise-induced shortness of breath is not uncommon in otherwise healthy young people. Based on the presenting symptoms alone, it is challenging to distinguish exercise-induced asthma (EIA) from exercise-induced obstruction of central airways, sometimes leading to diagnostic errors and inadequate treatment. Central airway obstruction usually presents with exercise-induced inspiratory symptoms (EIIS) during ongoing exercise. EIIS tends to peak towards the end of an exercise session or immediately after its completion, contradicting symptoms of EIA typically peaking 3-15 min after the exercise has stopped. EIIS is usually associated with some form of laryngeal obstruction. Transnasal flexible laryngoscopy performed continuously throughout an incremental exercise test from rest to exhaustion or to intolerable symptoms is usually diagnostic, and also provides information that is important for further handling and treatment. Reflecting the complex anatomy and functional features of the larynx, exercise-induced laryngeal obstruction (EILO) appears to be a heterogeneous condition. Contradicting previous beliefs, recent literature suggests that laryngeal adduction in a majority of cases starts in supraglottic structures and that vocal cord adduction (VCD) most often occurs as a secondary phenomenon. However, EILO is poorly understood and more and better research is needed to unravel causal mechanisms. The evidence base for treatment of EILO is weak. Speech therapy, psychotherapy, biofeedback, muscle training, anticholinergic aerosols have all been applied, as has laser supraglottoplasty. Randomized controlled trials with well-defined and verifiable inclusion and success criteria are required to establish evidence-based treatment schemes.

Vitamins C and E for asthma and exercise-induced bronchoconstriction.

BACKGROUND: The association between dietary antioxidants and asthma or exercise-induced bronchoconstriction (EIB) is not fully understood. Vitamin C and vitamin E are natural antioxidants that are predominantly present in fruits and vegetables; inadequate vitamin E intake is associated with airway inflammation. It has been postulated that the combination may be more beneficial than either single antioxidant for people with asthma and exercise-induced bronchoconstriction. OBJECTIVES: To assess the effects of supplementation of vitamins C and E versus placebo (or no vitamin C and E supplementation) on exacerbations and health-related quality of life (HRQL) in adults and children with chronic asthma. To also examine the potential effects of vitamins C and E on exercise-induced bronchoconstriction in people with asthma and in people without a diagnosis of asthma who experience symptoms only on exercise. SEARCH METHODS: Trials were identified from the Cochrane Airways Review Group Specialised Register and from trial registry websites. Searches were conducted in September 2013. SELECTION CRITERIA: We included randomised controlled trials of adults and children with a diagnosis of asthma. We separately considered trials in which participants had received a diagnosis of exercise-induced bronchoconstriction (or exercise-induced asthma). Trials comparing vitamin C and E supplementation versus placebo were included. We included trials in which asthma management for treatment and control groups included similar background therapy. Short-term use of vitamins C and E at the time of exacerbation or for cold symptoms in people with asthma is outside the scope of this review. DATA COLLECTION AND ANALYSIS: Two review authors independently screened the titles and abstracts of potential studies and subsequently screened full-text study reports for inclusion. We used standard methods as expected by The Cochrane Collaboration. MAIN RESULTS: It was not possible to aggregate the five included studies (214 participants). Four studies (206 participants) addressed the question of whether differences in outcomes were seen when vitamin C and E supplementation versus placebo was provided for participants with asthma, and only one of those studies (160 children) included a paediatric population; the remaining three studies included a combined total of just 46 adults. An additional study considered the question of whether differences in outcomes were noted when vitamin C and E supplementation was compared with placebo for exercise-induced asthma; this trial included only eight participants. The randomisation process of the trials were unclear leading us to downgrade the quality of the evidence. Four of the studies were double blind while the other study was single blind.None of these studies provided data on our two prespecified primary outcome measures: exacerbations and HRQL. Lung function data obtained from the studies were inconclusive. The only studies that provided any suggestion of an effect, and only with some outcomes, were the paediatric study, especially for children with moderate to severe asthma, and the small study on exercise-induced asthma. Even so, this evidence was judged to be at moderate/low quality. Only one study contributed data on asthma symptoms and adverse events, reporting no evidence of an effect of the intervention for symptoms and that one participant in the treatment group dropped out due to cystitis. AUTHORS' CONCLUSIONS: It is not possible to draw firm conclusions from this review with respect to the comparison of vitamin C and E supplementation versus placebo in the management of asthma or exercise-induced bronchoconstriction. We found only one study relevant to exercise-induced bronchoconstriction; most included participants came from studies designed to assess the effect of vitamin supplementation on the impact of atmospheric pollutants (such as ozone). Evidence is lacking on the comparison of vitamin C and E supplementation versus placebo for asthma with respect to outcomes such as HRQL and exacerbations, which were not addressed by any of the included studies.When compared with lung function tests alone, HRQL scores and exacerbation frequency are better indicators of the severity of asthma, its impact on daily activities and its response to treatment in a patient population. These end points are well recognised in good quality studies of asthma management. However, clinical studies of vitamins C and E in the management of asthma using these important end points of exacerbations and effects on quality of life are not available, and evidence is insufficient to support robust conclusions on the role of vitamin C and E supplementation in asthma and exercise-induced breathlessness.

[Impact of exercise, sport and rehabilitation therapy in asthma and COPD]. / Impact von Bewegung, Sport und Rehabilitation bei Asthma und COPD.

Patients with chronic obstructive pulmonary disease (COPD) and Asthma share increased physical inactivity as a characteristic and risk factor for the aggravation of their symptoms and marker of their health condition, respectively. Physical inactivity may be objectively measured by means of accelerometry superior to questionnaires. Physical inactivity is the reason for a reduced endurance capacity and a reduction of strength with concomitant decrease of skeletal muscle mass aggravating inflammation as a common pathophysiologic soil. Endurance training is recommended in the form of continuous and interval training having similar effects on endurance capacity executed on either a bike or as walking in patients with COPD und Asthma. Walking inherits the potential additional benefit of a reduction of fall risk which needs additional scientific evidence. This holds true especially for elderly subjects. Strength training is important because of the frequently atrophied skeletal musculature, which triggers the increase of the exercise-induced ventilation by early lactate acidosis and thereby aggravates dyspnea during exercise. An important aspect of therapy is the maintenance of the individualized training after discharge from hospital in the domestic environment taking into consideration training facilities, encounter groups and social circumstances. The objective measurement of physical activity has the potential to guide and control therapy. Because of the frequently present cardio-metabolic comorbidities the assessment of the exercise capacity as well an evaluation of nutrition should be included into a holistic therapeutical approach. An optimized bronchospasmolytic and anti-inflammatory therapy is the basis for a sufficient response to exercise training. In patients with asthma, a warm-up phase of at least 15 min prior to exercise is recommended. Redundant fear of exercise-induced attacks of asthma shall be avoided by doing so. If necessary, additional psychological support should be given.

Is yoga training beneficial for exercise-induced bronchoconstriction?

BACKGROUND: Some studies have shown the beneficial effects of yoga for individuals with bronchial hyperreactivity with regard to (1) a reduction in the use of rescue medication, (2) an increase in exercise capacity, and (3) an improvement in lung function. Despite the fact that yoga is promising as a new treatment for pediatric patients, further studies are needed to assess the use of this training for asthma management. OBJECTIVE: This study was performed to assess the beneficial effects of yoga in exercise-induced bronchoconstriction (EIB) in children. DESIGN: The study was prospective, with no control group. Participants were randomly chosen among the new patients at the unit. SETTING: This study was conducted in the Erciyes University School of Medicine, Pediatric Allergy Unit, in Kayseri, Turkey. PARTICIPANTS: Two groups of asthmatic children aged 6-17 y were enrolled in the study: (1) children with positive responses to an exercise challenge (n = 10), and (2) those with negative responses (n = 10). INTERVENTION: Both groups attended 1-h sessions of yoga training 2 ×/wk for 3 mo. OUTCOME MEASURES: Researchers administered spirometric measurement to all children before and immediately after participating in an exercise challenge. This process was performed at baseline and at the study's end. Age, gender, IgE levels, eosinophil numbers, and spirometric measurement parameters including forced expiratory volume in 1 sec (FEV1), forced expiratory flow 25%-75% (FEF25%-75%), forced vital capacity (FVC), peak expiratory flow percentage (PEF%), and peak expiratory flow rate (PEFR) were compared using the Mann-Whitney U test and the Wilcoxon test. A P value < .05 was considered significant. RESULTS: At baseline, no significant differences were observed between the groups regarding demographics or pre-exercise spirometric measurements (P > .05, Mann-Whitney U test). Likewise, no significant differences in spirometric measurements existed between the groups regarding the change in responses to an exercise challenge after yoga training (P > .05, Wilcoxon test). For the exercise-response-positive group, the research team observed a significant improvement in maximum forced expiratory volume 1% (FEV1%) fall following the exercise challenge after yoga training (P > .05, Wilcoxon test). All exercise-response-positive asthmatics became exerciseresponse-negative asthmatics after yoga training. CONCLUSION: This study showed that training children in the practice of yoga had beneficial effects on EIB. It is the research team's opinion that yoga training can supplement drug therapy to achieve better control of asthma.

Vitamin C for asthma and exercise-induced bronchoconstriction.

BACKGROUND: Dietary antioxidants, such as vitamin C, in the epithelial lining and lining fluids of the lung may be beneficial in the reduction of oxidative damage (Arab 2002). They may therefore be of benefit in reducing symptoms of inflammatory airway conditions such as asthma, and may also be beneficial in reducing exercise-induced bronchoconstriction, which is a well-recognised feature of asthma and is considered a marker of airways inflammation. However, the association between dietary antioxidants and asthma severity or exercise-induced bronchoconstriction is not fully understood. OBJECTIVES: To examine the effects of vitamin C supplementation on exacerbations and health-related quality of life (HRQL) in adults and children with asthma or exercise-induced bronchoconstriction compared to placebo or no vitamin C. SEARCH METHODS: We identified trials from the Cochrane Airways Group's Specialised Register (CAGR). The Register contains trial reports identified through systematic searches of a number of bibliographic databases, and handsearching of journals and meeting abstracts. We also searched trial registry websites. The searches were conducted in December 2012. SELECTION CRITERIA: We included randomised controlled trials (RCTs). We included both adults and children with a diagnosis of asthma. In separate analyses we considered trials with a diagnosis of exercise-induced bronchoconstriction (or exercise-induced asthma). We included trials comparing vitamin C supplementation with placebo, or vitamin C supplementation with no supplementation. We included trials where the asthma management of both treatment and control groups provided similar background therapy. The primary focus of the review is on daily vitamin C supplementation to prevent exacerbations and improve HRQL. The short-term use of vitamin C at the time of exacerbations or for cold symptoms in people with asthma are outside the scope of this review. DATA COLLECTION AND ANALYSIS: Two review authors independently screened the titles and abstracts of potential studies, and subsequently screened full text study reports for inclusion. We used standard methods expected by The Cochrane Collaboration. MAIN RESULTS: A total of 11 trials with 419 participants met our inclusion criteria. In 10 studies the participants were adults and only one was in children. Reporting of study design was inadequate to determine risk of bias for most of the studies and poor availability of data for our key outcomes may indicate some selective outcome reporting. Four studies were parallel-group and the remainder were cross-over studies. Eight studies included people with asthma and three studies included 40 participants with exercise-induced asthma. Five studies reported results using single-dose regimes prior to bronchial challenges or exercise tests. There was marked heterogeneity in vitamin C dosage regimes used in the selected studies, compounding the difficulties in carrying out meaningful analyses.One study on 201 adults with asthma reported no significant difference in our primary outcome, health-related quality of life (HRQL), and overall the quality of this evidence was low. There were no data available to evaluate the effects of vitamin C supplementation on our other primary outcome, exacerbations in adults. One small study reported data on asthma exacerbations in children and there were no exacerbations in either the vitamin C or placebo groups (very low quality evidence). In another study conducted in 41 adults, exacerbations were not defined according to our criteria and the data were not available in a format suitable for evaluation by our methods. Lung function and symptoms data were contributed by single studies. We rated the quality of this evidence as moderate, but further research is required to assess any clinical implications that may be related to the changes in these parameters. In each of these outcomes there was no significant difference between vitamin C and placebo. No adverse events at all were reported; again this is very low quality evidence.Studies in exercise-induced bronchoconstriction suggested some improvement in lung function measures with vitamin C supplementation, but theses studies were few and very small, with limited data and we judged the quality of the evidence to be low. AUTHORS' CONCLUSIONS: Currently, evidence is not available to provide a robust assessment on the use of vitamin C in the management of asthma or exercise-induced bronchoconstriction. Further research is very likely to have an important impact on our confidence in the estimates of effect and is likely to change the estimates. There is no indication currently that vitamin C can be recommended as a therapeutic agent in asthma. There was some indication that vitamin C was helpful in exercise-induced breathlessness in terms of lung function and symptoms; however, as these findings were provided only by small studies they are inconclusive. Most published studies to date are too small and inconsistent to provide guidance. Well-designed trials with good quality clinical endpoints, such as exacerbation rates and health-related quality of life scores, are required.

Treatment of exercise-induced bronchoconstriction.

Exercise-induced bronchoconstriction (EIB) describes the transient narrowing of the airways during, and particularly after exercise and occurs commonly in asthmatic individuals. Limitation of exercise capacity is a frequent complaint in all age groups, and severity of EIB ranges from mild impairment of performance to severe bronchospasm and a large reduction in FEV1. Treatment of EIB varies from daily to less frequent therapy, depending on the level of activity. In this article, the authors evaluate the treatment possibilities before, during, and after exercise. They also review medications currently used to treat EIB.

Seasonal Variation in Skin Sensitivity to Aeroallergens

PURPOSE: We previously demonstrated seasonal variation in sensitization to aeroallergens in a small group of patients with exercise-induced asthma. This study was performed to confirm the relationship in a much larger population. METHODS: The charts of 1,891 patients who received allergy skin prick tests were reviewed retrospectively. The test results from subjects aged < or =60 years were compared between the groups classified according to the season when the patients received the tests (spring: March-May, summer: June-August, fall: September-November, winter: December-February). The data from 25 respiratory allergy patients who received the tests two or more times and showed a positive response at least once were analyzed longitudinally. RESULTS: The most prevalent among 29 tested aeroallergens were house dust mites (HDMs) Dermatophagoides pteronyssinus and D. farinae. The skin sensitization rates to D. pteronyssinus (23.2% vs. 32.1%, P=0.004) and D. farinae (22.2% vs. 30.2%, P=0.009) were significantly lower in the summer and higher in the fall (38.3% vs. 26.6% and 35.6% vs. 25.3%; P=0.001 respectively) than those in other seasons in patients with a respiratory allergy (n=1,102). The sensitization rates to weed pollens in the fall (13.9% vs. 8.3%, P=0.006) and to Aspergillus fumigatus in the winter (2.9% vs. 0.7%, P=0.005) were significantly higher. In patients with non-respiratory allergy such as urticaria/anaphylaxis (n=340), the D. farinae sensitization rate was significantly lower in the summer also but higher in the spring. The trend of the HDM sensitization rate being lower in the summer and higher in the fall was observed in the longitudinal study. CONCLUSIONS: Skin sensitivity to aeroallergens such as HDMs, pollens, and molds demonstrates seasonal variation in respiratory allergy patients. Non-respiratory allergy patients also showed seasonal variation in sensitivity to aeroallergens, which might be related to the "priming" effect of allergens.

Vocal cord dysfunction in athletes: clinical presentation and review of the literature.

Vocal cord dysfunction (VCD) is a syndrome characterized by the intermittent, abnormal paradoxical adduction of the true vocal cords during respiration resulting in variable upper airway obstruction. It is also commonly referred to as paradoxical vocal fold motion disorder. Patients with VCD usually present with intermittent shortness of breath of varying intensity, wheezing, stridor, choking, throat tightness, voice changes, or cough, and these symptoms often resolve quickly after relaxation or cessation of activity. Since first described as a distinct clinical entity in 1983, VCD remains underrecognized and the underlying cause(s) is not fully understood. Several studies suggest psychogenic or laryngeal hyperresponsiveness as possible underlying causes. Although VCD may have many causes, it can be a unique problem, especially in athletes because it often mimics and can be easily mistaken for exercise-induced bronchospasm, which may result in unnecessary medical treatment and delay in diagnosis. A detailed history, physical examination, and pulmonary function tests with flow-volume loops are important for excluding other diagnoses; however, the gold standard method for diagnosing VCD is by observation of the vocal cords with flexible laryngoscopy. The mainstay of treatment includes behavioral management guided by a speech-language pathologist, but optimal therapy often requires a multidisciplinary team involving a variety of specialties, including certified athletic training, pulmonology, otolaryngology, speech-language pathology, gastroenterology, allergy and immunology, and psychology, as appropriate. We reviewed the medical literature for VCD specifically in athletes, and this article discusses in detail the definition, epidemiology, possible pathophysiology, diagnosis, and treatment options.

Exercise induced bronchospasm in physically fit female students of Kerman University and their pulmonary function tests.

INTRODUCTION: High prevalence of respiratory symptoms and bronchial hyper-responsiveness has been reported in professionals athletes, particularly in relation to climate and environment. However, the airway response to exercise in active population has been poorly investigated especially in women. The aim of this study was to examine pulmonary function test changes in physically fit female students of Kerman University. METHODS: Sixty physically fit female students (19 ± 1.12 years old) were randomly selected out of 500 students. Each subject underwent the physical fitness test (Couper test) of the maximal distance running in 12 min. The exercise induced bronchospasm (EIB) symptoms including coughing, wheezing, chest tightness, dyspnea, previously diagnosed asthma and allergy, the use of anti-asthmatics medication and the family history of asthma were recorded using a questionnaire. Pulmonary function tests including; forced vital capacity (FVC), forced expiratory volume in 1 s (FEV(1)), peak expiratory flow (PEF), and maximal expiratory flow at 50% of the FVC (MEF(50)) were measured at rest (baseline), immediately, 5, and 15 min after an exercise test. RESULT: The result of this study showed that the prevalence of the symptoms of EIB was 40.0%. There was not any significant difference in baseline PFT values between symptomatic and asymptomatic subjects. However, All PFT values of symptomatic subjects were significantly lower than asymptomatic immediately after exercise (p < 0.05 to p < 0.01). In addition, PFT values were significantly reduced in all times intervals for the symptomatic subjects (p < 0.05 to p < 0.01). CONCLUSION: The results showed a high prevalence of respiratory symptoms and EIB in healthy female students.

Exercise-induced bronchoconstriction update: therapeutic management.

Management of exercise-induced bronchoconstriction (EIB) should include both prevention and treatment directed toward the underlying asthma and bronchial hyperresponsiveness. Both nonpharmacologic and pharmacologic approaches should be followed. Preexercise warm-up, to take advantage of the refractory period that follows EIB, is an important preventive technique. Dietary interventions such as fish oil, vitamin D, and ascorbic acid have shown promising results. Beta 2-agonists are considered the most effective agents for EIB at this time but intermittent use is recommended to avoid tolerance or decreased effectiveness with daily regular use. Leukotriene inhibitors and mast cell stabilizing agents can be useful in EIB but are less effective than beta 2-agonists. Tolerance to beta 2-agonists is not prevented by concomitant use of inhaled corticosteroid but it is not known whether use of leukotriene inhibitors can affect tolerance. EIB in elite athletes with no underlying asthma may have a different pathogenesis.