Exercise-induced Asthma Research Articles

Midterm Effects of SARS-CoV-2 on Respiratory Function in Judokas With and Without Exercise-Induced Bronchoconstriction: A Retrospective Study.

The clinical consequences of coronavirus infection in elite judokas with exercise-induced bronchoconstriction (EIB) are unclear. We aimed to determine potential respiratory function abnormalities and recovery in athletes with and without EIB after severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Retrospective cohort study. Türkiye Olympic Preparation Centre. This retrospective study analyzed data collected from 25 consecutive elite judokas diagnosed with and without EIB and SARS-CoV-2 infection, routinely followed at an Olympic Sports Center between September 2020 and 2021. Respiratory muscle strength and pulmonary function data were collected before and up to 90 days after SARS-CoV-2 infection. Measurements included maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), FEV1/FVC ratio, and peak expiratory flow (PEF). Infected athletes with EIB had more markedly reduced respiratory muscle strength and pulmonary function than those without EIB. Maximal inspiratory pressure was decreased by 14% and MEP by 8% from baseline in infected athletes with EIB during follow-up. Likewise, FEV1 and FVC decreased by 4%. Maximal inspiratory pressure, MEP, FEV1, and FVC remained abnormal after 90 days of SARS-CoV-2 infection in EIB athletes but normalized rapidly in non-EIB athletes. Peak expiratory flow seemed unaffected during follow-up. Exercise-induced bronchoconstriction severity was moderately correlated with the maximum fall in MEP during follow-up. Severe acute respiratory syndrome coronavirus-2 infection notably decreases respiratory muscle strength and pulmonary function in judokas, especially those with pre-existing EIB, thereby prolonging spontaneous recovery time.

Evaluating serum periostin and YKL-40 as biomarkers for airway remodeling and hyperresponsiveness in pediatric asthma

BackgroundPeriostin and human chitinase-3-like protein 1 (YKL-40) have been suggested to be involved in the development of airway fibrosis and remodeling. This study aimed to investigate the relationship between serum periostin levels and airway hyperresponsiveness (AHR) and between serum YKL-40 levels and AHR in children with asthma, comparing periostin as a marker for Th2 inflammation and atopy with YKL-40. MethodsThe study involved children aged 6–15 years, comprising 75 with asthma and 29 healthy controls. We measured serum periostin and YKL-40 levels and performed exercise bronchial provocation tests, methacholine challenge tests, spirometry, and FeNO measurements. ResultsCompared to the healthy controls, asthmatic children exhibited significantly elevated levels of periostin (86.7 [71.0–104.0] vs 68.3 [56.0–82.0] ng/mL; P = 0.006) and YKL-40 (29.0 [15.0–39.5] vs 27.7 [14.0–34.1] ng/mL; P = 0.034). The subgroup analysis revealed that periostin levels were significantly higher in the atopic asthma group than in the healthy controls (P = 0.003), but not in the non-atopic asthma group. YKL-40 levels were elevated in both the atopic and non-atopic asthma groups compared to healthy controls (P = 0.012 and P = 0.001, respectively). Serum periostin levels were significantly correlated with the postexerceise maximum percentage decrease in forced expiratory volume (FEV1), as well as with fractional exhaled nitric oxide (FeNO) and blood eosinophil counts, but showed no significant correlation with overall lung function. Conversely, serum YKL-40 levels were significantly linked to the Z score of FEV1 and AHR to methacholine but not with AHR to exercise or FeNO or blood eosinophil count. ConclusionsPeriostin is linked to atopic asthma and correlates with exercise-induced bronchoconstriction, FeNO, and eosinophil counts, highlighting its role in Th2 inflammation. YKL-40 is a general asthma marker, indicating airway remodeling. These findings suggest that targeting these markers can improve personalized treatment strategies for pediatric asthma.

Examining the effect of salbutamol use in ozone air pollution by people with exercise-induced bronchoconstriction.

Previous studies based on animal models have raised concerns about salbutamol use in ozone air pollution with regard to ozone related lung injury. We conducted a double-blind, randomized, placebo-controlled crossover study including 18 subjects diagnosed with EIB by a eucapnic voluntary hyperpnea (EVH) test. Participants completed 30 min of standardized moderate to vigorous exercise in four conditions: ozone plus salbutamol; room air plus salbutamol; ozone plus placebo medication; and room air plus placebo medication. Spirometry, fraction of exhaled nitric oxide, and symptoms were measured before, immediately after, 30 min after and 1 h after exercise. Measurements between the four conditions were compared using percent change from pre to post exercise. There was a statistically significant difference between the salbutamol and placebo medication groups for spirometric variables including FEV1 (Estimate = 6.3, 95% CI: 4.23-8.37, p < 0.001). No differences were observed between ozone and room air exposures. There were no significant differences in FeNO response between experimental conditions. We found that salbutamol improved pulmonary function in individuals with EIB when exercising in ozone and did not increase eosinophilic airway inflammation as indicated by FeNO. This evidence suggests that it is safe for people with EIB to continue to use salbutamol as proscribed when ozone levels are elevated.

The impact of tangeretin combined with whey protein on exercise-induced bronchoconstriction in professional athletes: a placebo-controlled trial.

Exercise-induced bronchoconstriction (EIB) is highly prevalent in athletes. The objective of this study was to assess the therapeutic efficacy of daily tangeretin combined with whey protein supplementation over a period of 4weeks in professional athletes with EIB. Using a placebo-controlled, double-blind, paired, randomized trial design, a cohort of 30 professional athletes with EIB, consisting of 14 females and 16 males, was divided into two groups: the tangeretin combined with whey protein intervention group (TIG), and the placebo control group (PCG). Both the TIG and PCG underwent exercise challenge tests (ECT) and VO2max tests before (ECT1, V1) and after (ECT2, V2) the intervention. Blood (eosinophils, neutrophils, and basophils) and serum (interleukin-5, IL-5; interleukin-8, IL-8; Clara cell secretory protein-16, CC16; immunoglobulin E, IgE) levels were measured early in the morning of ECT1 and ECT2, respectively. Lung function was assessed immediately before and post-ECT immediately. Tangeretin combined with whey protein use for 4 weeks attenuated the decrease in forced expiratory volume in 1 s (FEV1) post trials (∆FEV1(ECT1-ECT2): mean (SD) TIG -7.51(6.9)% vs. PCG -2.33(11.49)%, p = 0.013). Tangeretin also substantially attenuated IL-5 concentration (∆IL-5(T1-T5): Tangeretin -19.4% vs Placebo + 8.37%, p = 0.022); IL-8 concentration (∆IL-8(T1-T5): Tangeretin -17.28% vs Placebo + 6.1%, p = 0.012); CC16 concentration (∆CC16(T1-T5): Tangeretin -11.77% vs Placebo + 24.19%); and IgE concentration in the serum (∆IgE(T1-T5): Tangeretin -24.1% vs Placebo -3.9%), and significantly decreased neutrophil count (∆N(T1-T5): Tangeretin -11.34% vs Placebo + 0.3%) and eosinophil count in blood (∆N(T1-T5): Tangeretin -38.5% vs Placebo + 4.35%). Compared with V1, VO2max (p = 0.042) and TLim (p = 0.05) of V2 were significantly increased in the TIG, and there was no significant change in the PCG. Meanwhile, six athletes in the TIG and 0 athletes in the PCG became EIB-negative at ECT2; the overall negative conversion rate of EIB was 40.00% in TCG. Additionally, the number of cough symptoms decreased from 9 to 3 and dyspnea from 4 to 2 in the TIG. After high-intensity exercise, athletes with EIB achieved significant improvements in lung function and blood inflammatory factors by combining tangeretin and whey protein supplementation. EIB athletes also showed longer exercise endurance and VO2max at 4 weeks after TI. In addition, some patient symptoms disappeared after combination supplementation. The effect of this treatment on professional athletes with EIB was beneficial.

Cardiac Fatigue in Male Athletes with Exercise-Induced Pulmonary Impairments After a Very Long-Distance Triathlon.

Prolonged strenuous exercise can transiently decrease cardiac function. Other studies have identified three major exercise-induced pulmonary changes: bronchoconstriction, dynamic hyperinflation and pulmonary oedema with reduced alveolar-capillary membrane diffusing capacity. This study investigated whether athletes with one of these pulmonary dysfunctions following a very long-distance triathlon exhibit similar cardiac alterations as those without dysfunctions. Sixty trained male triathletes (age 39 ± 9years) underwent baseline and post-race assessments, including echocardiography (with standard, 2D-strain and myocardial work assessments), spirometry and double-diffusion technique to evaluate alveolar-capillary membrane diffusing capacity for carbon monoxide (DMCO). Cardiac function in athletes with exercise-induced bronchoconstriction (> 10% decrease FEV1), dynamic hyperinflation (> 10% decrease inspiratory capacity) or impaired diffusion capacity (> 20% decrease DMCO/alveolar volume) were compared with those without these dysfunctions. The race lasted 14h 20min ± 1h 26min. Both systolic and diastolic cardiac functions declined post-race. Post-race, 18% of athletes had bronchoconstriction, 58% dynamic hyperinflation and 40% impaired diffusing capacity. Right and left ventricular standard and 2D-strain parameters were similar before the race in all subgroups and changed similarly post-race, except E/E', which decreased in the bronchoconstriction subgroup and increased in those with diffusion impairment. Global constructive work decreased by ~ 19% post-race (2302 ± 226 versus 1869 ± 328mmHg%, P < 0.001), more pronounced in athletes with diffusion impairment compared with others (- 26 ± 13 versus - 15 ± 9%, P = 0.001) and positively correlated with DMCO/alveolar volume reduction. After a very long-distance triathlon, bronchoconstriction and hyperinflation were not associated with significant cardiac changes, whereas impaired alveolar-capillary membrane diffusing capacity was associated with a more significant decline in myocardial function. These findings highlight the complex relationship between pulmonary gas exchange abnormalities and cardiac fatigue following prolonged strenuous exercise.

Exercise-induced bronchoconstriction

Exercise-induced bronchoconstriction

Exercise-induced bronchoconstriction

Exercise-induced bronchoconstriction

Investigation of exertional dyspnoea by cardiopulmonary exercise testing with continuous laryngoscopy

ObjectivesAbnormal breathlessness at maximal exercise may be caused by a range of conditions, including exercise-induced bronchospasm, breathing pattern disorder, or exercise-induced laryngeal obstruction. These three disorders may not be detected on standard cardiopulmonary exercise testing. The aim of this study was to describe diagnostic outcomes of an expanded protocol during cardiopulmonary exercise testing. DesignRetrospective cohort study. MethodsPatients presenting with abnormal breathlessness on maximal exercise underwent continuous laryngoscopy with cardiopulmonary exercise testing on a stationary cycle ergometer. Breathing pattern disorder was evaluated by video and ventilatory data. Pre- and post-exercise spirometry was performed. Results24 adult patients were evaluated; 10 were professional athletes. Mean age was 40 years (range 18–73). Nine of 24 (38 %) were diagnosed with exercise-induced laryngeal obstruction and referred for speech pathology. Six of these had supraglottic exercise-induced laryngeal obstruction; all were aged <30 years; 5/6 were professional athletes. One patient had breathing pattern disorder and was referred for physiotherapy; one had exercise-induced bronchospasm, requiring escalation of asthma medication; one had muscle tension dysphonia resulting in referral to an otolaryngologist who administered a laryngeal injection of botulinum toxin. A further four patients had unexplained lower maximal oxygen consumption with cardiac limitation and were referred for further cardiac investigation. ConclusionsIn patients reporting abnormal breathlessness at maximal exercise, this expanded exercise protocol provided diagnostic information in 66.7 % cases which contributed to further personalised management.

Managing Exercise-Induced Bronchoconstriction: A Comprehensive Review of Strategies for Athletes to Maintain Fitness and Health

Exercise-induced bronchoconstriction (EIB) significantly impacts athletes by impairing their performance and overall health. Characterized by airway narrowing during or after physical activity, EIB affects the quality of training and competition. This study employs a qualitative descriptive research model based on a comprehensive literature review to evaluate EIB management strategies in athletes. We systematically collected data from trusted scientific databases—Scopus, Science Direct, and Google Scholar—using keywords such as "Exercise-Induced Asthma," "Athlete," and "Sport." Relevant articles were identified, and key terms related to EIB management were reviewed. The data, including study designs, research objectives, sample sizes, and findings, were compiled and analyzed to determine effective management approaches. Key findings indicate that accurate diagnosis using spirometry and bronchial provocation tests is essential. Pharmacological management primarily involves inhaled corticosteroids (ICS) to reduce inflammation and control EIB, while short-acting beta agonists (SABAs) offer only temporary relief. Non-pharmacological strategies include avoiding triggers, implementing proper warm-up routines, and using breathing techniques. Supervised aerobic exercise programs were shown to improve cardiovascular fitness without worsening EIB symptoms. The study also reviewed the impact of environmental factors, such as air pollution and post-COVID-19 conditions, on EIB. Recommendations include personalized asthma action plans, training for coaches on environmental triggers, and exercising in controlled conditions. This study highlights the need for a holistic approach combining pharmacological and non-pharmacological methods to manage EIB effectively and maintain athletic performance. Further research is warranted to develop tailored strategies for athletes with EIB.

Associations Between Pesticide Chemical Exposure Students with Respiratory Infections and Asthma Symptoms in Iraq

Background: There are relationships between pesticide chemical exposures (PCE) found in schools, and not enough research has been done on schoolchildren's allergies and respiratory health. In order to provide objective assessments of the PMECs that young students are exposed to in the classroom and to establish a link between schoolchildren's respiratory infections and asthma and exposure to major air pollutants found in classrooms, a survey was carried out in a sizable sample of primary school classrooms in Iraq. Methods: Children from a randomly chosen sample were the subjects of a cross-sectional study that also included a case-control analysis of public schools in Karbala. A total of 500 pupils from six junior primary schools in Karbala (mean age 10 years, SD 65.7) took part (97% participation rate). Results: The study included a physician visit with skin prick testing for common allergens, an exercise-induced asthma (EIA) screening test, and a parent-completed standardized health questionnaire. Out of 500 youngsters, 10 (2%) had a persistent respiratory condition. Although not very large, the baseline difference in mean age was statistically significant. Conclusion: Children in Iraq who were exposed to pesticides had long-term respiratory problems and illnesses.

Beta2-adrenergic agonist salbutamol exhibits enantioselective disposition in skeletal muscle of lean young men following oral administration.

Salbutamol is a common short-acting beta2-adrenergic agonist used in treatment of asthma and exercise-induced bronchoconstriction but also possesses anabolic and metabolic actions in skeletal muscle. As a chiral compound, salbutamol is a racemic 1:1 mixture of two enantiomers, (R)-salbutamol and (S)-salbutamol, which exhibit divergent pharmacokinetic and pharmacodynamic actions. Despite salbutamol being available for decades, information on the enantioselective disposition of salbutamol enantiomers in human skeletal muscle is absent. In this study, we determined concentrations of (R)-salbutamol and (S)-salbutamol by UHPLC-MS/MS in arterial plasma and vastus lateralis muscle samples from 12 lean young men 2½ and 7 h following ingestion of 24 mg oral salbutamol. Mean (range) arterial plasma concentrations were 10-fold higher (p < 0.001) for (S)-salbutamol than (R)-salbutamol, being 33(9-62) and 49(30-84) ng·mL-1 for (S)-salbutamol and 4 (1-6) and 4 (2-5) ng·mL-1 for (R)-salbutamol 2½ and 7 h following administration, respectively, reflecting faster elimination of the (R)-enantiomer. Mean (range) muscle concentrations were higher (p < 0.001) for (S)-salbutamol than (R)-salbutamol 2½h (0.17 [0.1-0.26] vs. 0.04 [0.02-0.06]) and 7 h (0.31 [0.21-0.46] vs. 0.06 [0.04-0.12] ng·mgd.w. -1) after administration. However, muscle:plasma partition coefficient was two-fold higher (p < 0.001) for (R)-salbutamol than (S)-salbutamol 7 h following administration. These observations demonstrate that oral salbutamol exhibits enantioselective disposition in systemic circulation and muscle favoring the (S)-enantiomer but with higher relative partitioning of the (R)-enantiomer in skeletal muscle. Furthermore, the concentration-time profiles of salbutamol enantiomers are different in skeletal muscle and systemic circulation following oral ingestion. These findings have implications for the application of chiral switch (R)-salbutamol in doping control.

Comparing prevalence of food allergy in exercise-induced bronchoconstriction vs asthma

Comparing prevalence of food allergy in exercise-induced bronchoconstriction vs asthma

Exercise-Induced Bronchoconstriction in Children: State of the Art from Diagnosis to Treatment.

Exercise-induced bronchoconstriction (EIB) is a common clinical entity in people with asthma. EIB is characterized by postexercise airway obstruction that results in symptoms such as coughing, dyspnea, wheezing, chest tightness, and increased fatigue. The underlying mechanism of EIB is not completely understood. "Osmotic theory" and "thermal or vascular theory" have been proposed. Initial assessment must include a specific work-up to exclude alternative diagnoses like exercise-induced laryngeal obstruction (EILO), cardiac disease, or physical deconditioning. Detailed medical history and clinical examination must be followed by basal spirometry and exercise challenge test. The standardized treadmill running (TR) test, a controlled and standardized method to assess bronchial response to exercise, is the most adopted exercise challenge test for children aged at least 8 years. In the TR test, the goal is to reach the target heart rate in a short period and maintain it for at least 6 min. The test is then followed by spirometry at specific time points (5, 10, 15, and 30 min after exercise). In addition, bronchoprovocation tests like dry air hyperpnea (exercise and eucapnic voluntary hyperpnea) or osmotic aerosols (inhaled mannitol) can be considered when the diagnosis is uncertain. Treatment options include both pharmacological and behavioral approaches. Considering medications, the use of short-acting beta-agonists (SABA) just before exercise is the commonest option strategy, but daily inhaled corticosteroids (ICS) can also be considered, especially when EIB is not controlled with SABA only or when the patients practice physical activity very often. Among the behavioral approaches, warm-up before exercise, breathing through the nose or face mask, and avoiding polluted environments are all recommended strategies to reduce EIB risk. This review summarizes the latest evidence published over the last 10 years on the pathogenesis, diagnosis using spirometry and indirect bronchoprovocation tests, and treatment strategies, including SABA and ICS, of EIB. A specific focus has been placed on EIB management in young athletes, since this condition can not only prevent them from practicing regular physical activity but also competitive sports.

The complicated relationship between asthma and swimming

Introduction: Apart from pharmacological treatment, non-pharmacological strategies including physical activity play a significant role in the management of asthma. The aim of this paper is to examine various topics related to swimming and asthma. They include the detailed effect of swimming on asthma control,the potential role of swimming in early childhood asthma development, exercise induced asthma in swimmers as well as the relationship between asthma and cold water swimming. Review methods: This article is based on the literature found in the PubMed Database from the period of 1971-2024 with the use of keywords such as “asthma”, “swimming”, “cold water swimming”, “exercise induced asthma”, “childhood asthma” Description of the state of knowledge: Swimming is a safe form of physical activity for asthma patients.Swimming training enhances aerobic capacity, reduces exercise-induced bronchoconstriction and improves lung function in both pediatric and adult patients. However, there is a concern regarding indoor swimming pools that chlorine can potentially induce airway inflammation. There is research suggesting that early life swimming pool exposure may contribute to the asthma development in atopic children. There is some premise to the thought that cold water swimming may help alleviate asthma symptoms, but it also carries many risks.Swimming is a major cause of exercise induced asthma in professional athletes. Conclusions: Alongside appropriate pharmacological treatment, swimming is a valuable strategy in asthma management in both pediatric and adult asthma patients. The risks of chlorinating pools are still not known to outweigh the benefits of swimming for asthmatics. Further research should be carried out on safety of early swimming in atopic children. Cold water swimming should also be evaluated in terms of safety and potential benefits for asthma patients.

Exercise-induced bronchoconstriction in adolescent recreational athletes: Potential screening strategies.

Intense physical exercise in athletes increases the risk to develop exercise-induced bronchocontriction (EIB). We aimed to study EIB prevalence and explore methods for effective EIB screening. Three hundred twenty-seven adolescent athletes (12-18 years) performing at least 12 h of sports a week were included. The evaluation consisted of spirometry, eucapnic voluntary hyperpnoea test (EVH) to evaluate for EIB, FeNO, skin prick testing, blood sampling (serum markers of epithelial damage and mast cell activation), and questionnaires (AQUA©, ACT, ACQ, and exposure and symptom-related questions). Of all athletes, 22% tested positive for EIB (n = 72), 14% reported a previous asthma diagnosis and 40% were atopic. Eighty percent of EIB+ athletes did not use any inhalation therapy. EIB+ athletes were significantly younger, had decreased FEV1/FVC (%), and increased post-EVH-reversibility (%) post-salbutamol compared with EIB- athletes. Furthermore, EIB was significantly associated with previous asthma diagnosis and atopy. The best predictors for a positive EVH test were AQUA© score ≥ 6 (sensitivity of 78%, p = .0171) and wheezing during exercise (specificity of 82%, p = .0002). FeNO negatively and significantly correlated with maximal fall in FEV1 post-EVH test in atopic athletes (r = -.2735, p = .0056). Maximal fall in FEV1 was also associated with prior PM10 exposure (p = .036). Serum markers of epithelial damage were significantly associated with training type, training intensity, EIB severity, and prior air pollution exposure. Our findings support the effectiveness of a systematic respiratory screening approach, including baseline questionnaires, lung function tests, and FeNO measurement, to improve EIB detection in adolescent athletes in whom respiratory response to EVH testing is associated with prior exposure to air pollution.

Terapi &lt;i&gt;Montelukast &lt;/i&gt;pada Asma

Asthma is a chronic inflammatory respiratory condition caused by various inflammatory mediators, including those from the arachidonic acid pathway, which serves as a precursor for leukotrienes and prostaglandins. Leukotriene receptor antagonists (LTRAs) have been approved since 1998 as a treatment for asthma. Montelukast is one of the LTRAs that is useful for asthma control, including cases that accompanied by allergic rhinitis. A daily dose of 5-10 mg is recommended for persistent asthma as the preferred controller. LTRAs are not recommended for acute asthma exacerbation due to their relatively slow onset, but they are beneficial in preventing exacerbations. They are also indicated for exercise-induced asthma (EIA), and can be taken 2 hours prior to exercise. Montelukast can be administered as monotherapy or added to LABA-ICS therapy. It is suitable for adults, children, and infants over 1 year of age, preferably taken at night to prevent symptoms in the early morning. Possible side effects include respiratory tract infections, abdominal pain, diarrhea, and neuropsychiatric disorders. Montelukast is considered safe for use during pregnancy and breastfeeding. Physicians should provide comprehensive education for patients regarding medication compliance and the potential risks of side effects. Regular daily use of montelukast is beneficial in preventing acute exacerbations in asthma patients.

The Olympics have arrived: The challenge of exercise-induced bronchoconstriction in athletes.

The Olympics have arrived: The challenge of exercise-induced bronchoconstriction in athletes.

Breathing pattern changes in response to bronchoconstriction in physically active adults

Objectives To determine whether Opto-Electronic Plethysmography (OEP) can distinguish Exercise-Induced Bronchoconstriction (EIB) breathing patterns by comparing individuals with and without EIB, and between broncho-constriction and recovery. Breathing pattern was quantified in terms of regional contribution, breathing timing, and the phase between chest sub-compartments which indicates the synchronization in movement of the different sub-compartments. Methods Individuals (n = 47) reporting no respiratory symptoms and no history of any respiratory disease or disorder were assumed to have a healthy breathing pattern. Of 38 participants reporting respiratory symptoms during exercise, and/or a previous diagnosis of asthma or EIB, 10 participants had a positive result to the Eucapnic Voluntary Hyperpnea test, defined as a fall of at least 10% in FEV1 from baseline at two consecutive time points and were classified into the EIB group. OEP data was obtained from 89 markers and an 11-camera motion capture system operating at 100 Hz as follows: pre- and post-EVH challenge, and post-inhaler in participants who experienced a bronchoconstriction, and 2) for the healthy group during tidal breathing. Results RCpRCa-Phase (upper versus lower ribcage), RCaS-Phase (lower ribcage versus shoulders), and RCpS-Phase (upper ribcage versus shoulders) differed between bronchoconstriction and rest in athletes with EIB and rest in healthy participants (p < 0.05), in all cases indicating greater asynchrony post-bronchoconstriction, and later movement of the abdominal ribcage (RCa) post-bronchoconstriction. RCpS-Phase was different (p < 0.05) between all conditions (rest, post-bronchoconstriction, and post-inhaler) in EIB. Conclusions OEP can characterize and distinguish EIB-associated breathing patterns compared to rest and individuals without EIB at rest.

The prevalence of exercise-induced bronchoconstriction in non-asthmatic swimmers: A systematic review and meta-analysis

The prevalence of exercise-induced bronchoconstriction in non-asthmatic swimmers: A systematic review and meta-analysis

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.