Prevalence and mechanisms of development of asthma and airway hyperresponsiveness in athletes

Seasonal characteristics of ambient temperature variation (DTR, TCN, and TV0-t) and air pollutants on childhood asthma attack in a dry and cold city in China

Very few researches have concentrated on a variety of time scales to evaluate the association between temperature variation (TV) and childhood asthma (CA), and the evidence for the interaction of air pollutants on this association is lacking. In this study, we aim to estimate the relative risks (RRs) of CA due to TV by following metrics: diurnal temperature range (DTR), temperature changes between neighboring days (TCN), and temperature variability (TV_0-t); to quantify the seasonal attributable fraction (AF) and number (AN) of CA due to TV; to examine the interactive effects of the TV and air pollutants on CA in different seasons. We mainly applied distributed lagged nonlinear model (DLNM) and conditional Poisson models to evaluate the associations between TV and outpatient visits for CA during 2014-2019 in Lanzhou, China. Additionally, the bivariate response surface model was used to examine the interplay effect of air pollutants. We found that in warm season, the risks of DTR maximum at lag5 (RR = 1.073, 95% CI: 1.017-1.133); TCN showed protective effect. In cold season, the risks of DTR peaked at lag8 (RR = 1.063, 95% CI: 1.027-1.100); the risks of TCN maximum at lag0 (RR = 1.058 95% CI: 1.009-1.109); the estimation of total cases maximized at TV_0-4 in cold season (RR = 1.039 at TV_0-3, 95% CI: 1.001, 1.077) and was the lowest at TV_0-1 in warm season (RR = 0.999, 95% CI: 0.969, 1.030). In addition, the response surface model graphically pictured ambient air pollutants enhanced the DTR/TV_0-4-CA effect for girls. In conclusion, the RRs of CA are markedly increased by TV exposure, particularly during the colder months. A combined evaluation of DTR, TCN, TV_0-5∼TV_0-6, NO₂, SO₂, and PM_2.5 should be used to identify the adverse effects of TV on CA.

Prevalence of Asthma among Norwegian Elite Athletes

Objective

Asthma is a common problem among elite athletes and represents a health risk interfering with the athlete's performance status. This study aimed to evaluate the asthma prevalence among Norwegian summer and winter elite athletes and asthma prevalence across sport categories. We also aimed to examine whether bronchial hyperresponsiveness (BHR), lung function, fraction of exhaled nitric oxide (FENO), and allergy status differed between asthmatic and non-asthmatic elite athletes.

Methods

Norwegian athletes qualifying for the Beijing Olympic Summer Games 2008 (n = 80) and the Vancouver Olympic Winter Games 2010 (n = 55) were included. The athletes underwent clinical respiratory examination including lung function measurement, methacholine bronchial challenge for assessment of BHR, FENO, and skin prick testing. Asthma was diagnosed based on respiratory symptoms and clinical examination including objective measurements.

Results

Asthma was more prevalent among winter athletes (50%) than summer athletes (20%). Thirty-three (52%) endurance athletes, 3 (6%) team sport athletes, and 7 (33%) technical sport athletes had medically diagnosed asthma. Significantly lower lung function (p < 0.001) and higher prevalence of severe BHR (p < 0.001) were found in asthmatic athletes compared with non-asthmatic athletes.

Conclusion

Asthma is common among Norwegian elite athletes, with winter and endurance athletes showing the highest prevalence. Asthmatic athletes were characterized by lower lung function and more severe BHR compared with non-asthmatic counterparts. The high prevalence among winter and endurance athletes demonstrates a need for increased attention to prevent and reduce the prevalence of asthma among those athletes.

Association Between Air Pollutants and Pediatric Respiratory Outpatient Visits in Zhoushan, China

Objective

This study aimed to explore the time-series relationship between air pollutants and the number of children's respiratory outpatient visits in coastal cities.

Methods

We used time series analysis to investigate the association between air pollution levels and pediatric respiratory outpatient visits in Zhoushan city, China. The population was selected from children aged 0–18 who had been in pediatric respiratory clinics for eight consecutive years from 2014 to 2020. After describing the population and weather characteristics, a lag model was used to explore the relationship between outpatient visits and air pollution.

Results

We recorded annual outpatient visits for different respiratory diseases in children. The best synergy lag model found a 10 μg/m³ increase in PM_2.5 for every 4–10% increase in the number of pediatric respiratory outpatient visits (P < 0.05). The cumulative effect of an increase in the number of daily pediatric respiratory clinics with a lag of 1–7 days was the best model.

Conclusions

PM_2.5 is significantly related to the number of respiratory outpatient visits of children, which can aid in formulating policies for health resource allocation and health risk assessment strategies.

The Diamond League athletic series: does the air quality sparkle?

Urban air pollution can have negative short- and long-term impacts on health, including cardiovascular, neurological, immune system and developmental damage. The irritant qualities of pollutants such as ozone (O₃), nitrogen dioxide (NO₂) and particulate matter (PM) can cause respiratory and cardiovascular distress, which can be heightened during physical activity and particularly so for those with respiratory conditions such as asthma. Previously, research has only examined marathon run outcomes or running under laboratory settings. This study focuses on elite 5-km athletes performing in international events at nine locations. Local meteorological and air quality data are used in conjunction with race performance metrics from the Diamond League Athletics series to determine the extent to which elite competitors are influenced during maximal sustained efforts in real-world conditions. The findings from this study suggest that local meteorological variables (temperature, wind speed and relative humidity) and air quality (ozone and particulate matter) have an impact on athletic performance. Variation between finishing times at different race locations can also be explained by the local meteorology and air quality conditions seen during races.

Circadian rhythm of airways caliber and its autonomic modulation

The autonomic nervous system (ANS) is one of the effector pathways for circadian variation of many physiological parameters. Autonomic tone and airways caliber have been reported to exhibit circadian variation in separate studies. A simultaneous investigation of heart rate variability (HRV) and airway caliber might ascertain how airway caliber is modulated by autonomic tone. This study was planned to identify the variations in airway caliber and autonomic function tone during a 24-hour span. A total of 56 healthy male subjects with almost similar daily routines were studied. Time domain, frequency domain and nonlinear analysis of R-R interval from 5 min electrocardiogram (ECG) was done seven times during the daytime wake span at 3-hour intervals starting at 05:00 h in the morning until 23:00 h in the night. Simultaneously peak expiratory flow rate (PEFR) was determined using a mini Wright's peak flow meter. Rhythmometric analysis was done for PEFR and HRV parameters. Significant circadian variation in low frequency (LF) and high frequency (HF) variance was identified in this group of healthy subjects. The circadian rhythm of LF variance was characterized by a gradual increase and corresponding reciprocal change in HF variance from morning until night. The LF/HF ratio and SD2/SD1 ratio reflecting sympatho-vagal balance showed low to high values from morning to evening. The acrophase of the PEFR temporal pattern is similar to that of LF power and almost opposite in phase to that of HF power. PEFR is positively correlated with LF power. The circadian rhythm of airway caliber co-varies with cardiac autonomic tone. It appears that the temporal pattern of cardiac autonomic tone precedes in time that of airways caliber, thereby suggesting the latter operates under the modulatory effect of the 24-hour pattern in sympatho-vagal balance.

Association between the Ratio of FEV₁ to FVC and the Exposure Level to Air Pollution in Neversmoking Adult Refractory Asthmatics Using Data Clustered by Patient in the Soonchunhyang Asthma Cohort Database

Using real-world cases, asthma-related clinical data were clustered by patient; 5% of all asthmatics were found to have refractory asthma (RA) with a relatively low lung function (forced expiratory volume in 1 s/forced vital capacity (FEV₁/FVC) less than 80%). Using a multilevel study design for clustered spirometry data observed between 2005 and 2014, we evaluated the association between changes in the ratio of FEV₁ to FVC and variations in acute exposure to air pollution. We analyzed 2310 episodes of RA from 214 neversmoking patients. In spring, a 1 µg/m³ increase in concentration of particles ≤10 μm (PM10) on Lag 1 significantly reduced the ratio by 0.4% (95% confidence interval (CI): 0.1⁻0.7%) after adjusting for sex, age, body mass index (BMI), and total Immunoglobulin E (IgE) level. Unit (ppb) increase in SO₂ concentration on Lag 3 and 4 in fall and on Lag 6 in winter significantly reduced the ratio by 2 to 3% (p < 0.05). We found that acute exposure to PM10 in spring or SO₂ in fall or winter were positively associated with lung function drop indicating necessity of control strategies of target air pollutant source by season to protect susceptible population.

Physical activity among Canadian adults with obstructive respiratory diseases

The objective of this study was to investigate the amount and modes of physical activity in which adults with obstructive respiratory disease engage. Data from respondents with self-reported asthma (n = 4293), chronic obstructive pulmonary disease (COPD) (n = 3118), both diseases (n = 1569), and neither obstructive respiratory disease (n = 64 175); these data are from the Canadian Community Health Survey (2011-2012). Logistic regressions were used to assess associations between modes of physical activity and type of respiratory disease. Linear regressions were used to investigate the association between daily energy expenditure and respiratory disease. Adults with COPD and both diseases had the lowest participation in all modes of physical activity. Those with both diseases were less likely to report walking (odds ratio (OR) = 0.74, 95% confidence interval (CI) = 0.63-0.88), while those with COPD were less likely to report participation in endurance activities (OR = 0.79, 95% CI = 0.68-0.92), compared with those with neither obstructive respiratory disease. Those with asthma had similar daily energy expenditure levels and physical activity preferences compared with those with neither obstructive respiratory disease. In conclusion, adults with COPD and both asthma and COPD were less likely to engage in common activities such as walking, while physical activity levels among adults with asthma did not differ from the general population.

Asthma symptoms, mannitol reactivity and exercise-induced bronchoconstriction in adolescent swimmers versus tennis players

Background

Strenuous physical activity at an elite level is associated with an increased risk for asthma and, in some sports, also prevalence of allergies. The aim of this study was to investigate the prevalence of asthma and allergy among elite swimmers and tennis players and compare airway hyperreactivity to mannitol and exercise.

Materials and methods

One hundred and one adolescent swimmers and 86 tennis players answered a questionnaire about respiratory symptoms and allergy and performed mannitol challenge and sport-specific exercise challenge. Atopy was assessed and fractional exhaled nitric oxide was measured. Mannitol positivity was defined as drop in FEV₁ ≥15% (ordinary criteria) and/or β₂-reversibility (≥15%) after provocation (extended criteria). A positive exercise test was defined as a drop in FEV₁ ≥10% (ordinary criteria) and/or β₂-reversibility (≥15%) after provocation (extended criteria). Club cell protein (CC16) was measured in urine before and after the challenges.

Results

Asthma symptoms were common in both groups. More swimmers had exercise-induced symptoms (77% versus 50%) and current asthma symptoms (56% versus 38%), compared to the tennis players. More swimmers also had a positive mannitol challenge test both using ordinary (26% versus 6%) and extended criteria (43% versus 17%), while the number of positive exercise tests did not differ. After exercise (but not mannitol) challenge, CC16 level was increased in both groups, but to a higher extent in tennis players. There were no differences in atopy, rhinitis or fractional exhaled nitric oxide.

Conclusion

We found a high prevalence of asthma among elite swimmers and tennis players and a higher frequency of current asthma and positive mannitol challenge tests among the swimmers. This indicates an unfavorable exercise environment.

Compact Eucapnic Voluntary Hyperpnoea Apparatus for Exercise-Induced Respiratory Disease Detection

Eucapnic voluntary hyperpnoea (EVH) challenge provides objective criteria for exercise-induced asthma (EIA) or exercise-induced bronchoconstriction (EIB), and it was recommended to justify the use of inhaled β₂-agonists by athletes for the Olympics. This paper presents the development of a compact and easy-to-use EVH apparatus for assessing EIB in human subjects. The compact apparatus has been validated on human subjects and the results have been compared to the conventional EVH system. Twenty-two swimmers, including eleven healthy subjects and eleven subjects who had been physician-diagnosed with asthma, were recruited from sport and recreation centers throughout Auckland, New Zealand. Each subject performed two EVH challenge tests using the proposed breathing apparatus and the conventional Phillips EVH apparatus on separate days, respectively. Forced expiratory volume in one second (FEV₁) was measured before and after the challenges. A reduction in FEV₁ of 10% or more was considered positive. Of the eleven subjects who were previously diagnosed with asthma, EIB was present in all subjects (100%) in the compact EVH group, while it was presented in ten subjects (90.91%) in the conventional EVH challenge group. Of the eleven healthy subjects, EIB was present in one subject (4.55%) in the compact EVH group, while it was not present in the conventional EVH group. Experimental results showed that the compact EVH system has potential to become an alternative tool for EIB detection.

Airway Hyperresponsiveness in Asthma: Measurement and Clinical Relevance

Airway hyperresponsiveness is a characteristic feature of asthma, and its measurement is an important tool in its diagnosis. With a few caveats, methacholine bronchial provocation by a 2-minute tidal breathing method is highly sensitive; a negative test result (PC₂₀ > 16 mg/mL, PD₂₀ > 400 μg) rules out current asthma with reasonable certainty. A PC₂₀ value of less than 1 mg/mL/PD₂₀ value of less than 25 μg is highly specific (ie, diagnostic) but quite insensitive for asthma. For accurate interpretation of the test results, it is important to control and standardize technical factors that have an impact on nebulizer performance. In addition to its utility to relate symptoms such as cough, wheeze, and shortness of breath to variable airflow obstruction (ie, to diagnose current asthma), the test is useful to make a number of other clinical assessments. These include (1) evaluation of patients with occupational asthma, (2) evaluation of patients with exercise-induced respiratory symptoms, (3) evaluation of novel asthma medications, (4) evaluation of relative potency of inhaled bronchodilators, (5) as a biomarker to adjust anti-inflammatory therapy to improve clinical outcomes, and (6) in the evaluation of patients with severe asthma to rule out masqueraders such as laryngeal dysfunction. The actual mechanism of altered smooth muscle behavior in asthma that is assessed by direct (eg, methacholine) or indirect (eg, allergen) bronchial provocation remains one of the most fundamental questions related to asthma that needs to be determined. The test is underutilized in clinical practice.

Asthma prevalence in German Olympic athletes: A comparison of winter and summer sport disciplines

BACKGROUND

Prevalence of asthma in elite athletes shows very wide ranges. It remains unclear to what extent this is influenced by the competition season (winter vs. summer) or the ventilation rate achieved during competition. The aim of this study was to evaluate prevalence of asthma in German elite winter and summer athletes from a wide range of sport disciplines and to identify high risk groups.

METHODS

In total, 265 German elite winter athletes (response 77%) and 283 German elite summer athletes (response 64%) answered validated respiratory questionnaires. Using logistic regression, the asthma risks associated with competition season and ventilation rate during competition, respectively, were investigated. A subset of winter athletes was also examined for their FENO-levels and lung function.

RESULTS

With respect to all asthma outcomes, no association was found with the competition season. Regarding the ventilation rate, athletes in high ventilation sports were at increased risk of asthma, as compared to athletes in low ventilation sports (doctors' diagnosed asthma: OR 2.32, 95% CI 1.19-4.53; use of asthma medication: OR 4.46, 95% CI 1.52-13.10; current wheeze or use of asthma medication: OR 2.78, 95% CI 1.34-5.76). Athletes with doctors' diagnosed asthma were at an approximate four-fold risk of elevated FENO-values.

CONCLUSIONS

The clinically relevant finding of this study is that athletes' asthma seems to be more common in sports with high ventilation during competition, whereas the summer or winter season had no impact on the frequency of the disease. Among winter athletes, elevated FENO suggested suboptimal control of asthma.

Comparative Study of Bronchial Hyperresponsiveness Between Football and Judo Groups in Prepubertal Boys

BACKGROUND

Exercise induced bronchospasm (EIB) commonly occurs during exercise. The comparative effects of different sports on airway responsiveness among prepubertal boys remain to be determined.

OBJECTIVES

To assess differences in post exercise spirometry between footballers, judokas and a control group in prepubertal boys.

PATIENTS AND METHODS

A total of ninety six prepubertal boys were studied. Bronchial hyper responsiveness (BHR) to exercise challenge test was defined by a diagnosis of baseline spirometry, followed by an incremental exercise test. To date, the best test to confirm EIB may simply be standard pulmonary function testing before and after high-intensity exercise. A 10% or greater post-challenge fall in forced expiratory volume in FEV1 is used as a diagnostic criterion.

RESULTS

There was no significant difference in baseline spirometry between all groups (P > 0.05). The post exercise spirometry test revealed the presence of EIB in 16 of 32 (50%) footballers against 9 out of 32 (28.12%) in both judokas and control subjects at 5 min after the exercise. Also, there was a significantly higher decrease (P < 0.05) in mean FEV1 at 5 minuts in footballers (-9.60 ± 6.18) compared to judokas (-5.41 ± 5.85).

CONCLUSIONS

The footballers have more BHR than judokas, especially at 5min after the exercise. This may be due to prolonged hyperventilation, atopy and increased exposure to inhaled allergens and pollutants during training and competition.

Developing and emerging clinical asthma phenotypes

For more than a century, clinicians have attempted to subdivide asthma into different phenotypes based on triggers that cause asthma attacks, the course of the disease, or the prognosis. The first phenotypes that were described included allergic asthma, intrinsic or nonallergic asthma, infectious asthma, and aspirin-exacerbated asthma. These phenotypes are being reviewed elsewhere in this issue of the journal. The present article focuses on developing and emerging clinical asthma phenotypes. First, asthma phenotypes that are associated with environmental exposures (occupational agents, cigarette smoke, air pollution, cold dry air); second, asthma phenotypes that are associated with specific symptoms or clinical characteristics (cough, obesity, adult onset of disease); and third, asthma phenotypes that are based on biomarkers. This latter approach is the most promising because it attempts to identify asthma phenotypes with different underlying mechanisms so that therapies can be better targeted toward disease-specific features and disease outcomes can be improved.

Are former athletes more prone to asthma?

OBJECTIVE

We have designed the present study to compare prevalent lifetime cases of diagnosed asthma or exercise-induced asthma, as well as current related respiratory symptoms, across two different levels of former athletes and non-athletes.

METHODS

Demographic, behavioral, and asthma history information, as well as current related respiratory symptoms, were obtained through a questionnaire from 627 subjects (290 former elite and 201 non-elite athletes that competed between 1969 and 2005, and 136 control subjects that had never been athletes).

RESULTS

Non-athletes presented a higher percentage of subjects reporting the existence of symptoms associated with exercise or vigorous activities. Former athletes who reported having practiced mostly in indoor facilities presented significant lower risk for asthma than outdoor athletes (Odds Ratio = 0.48, 95% CI = 0.25-0.94). Multiple regression analysis (where "B" refers to unstandardized coefficients) showed that former elite (B = -0.85, p < .001) and non-elite athletes (B = -0.70, p < .001) were less prone to be affected by asthma-related symptoms than non-athletes. Athletes with careers that lasted more than 20 years were more likely to possess asthma-related symptoms than the ones with shorter careers (3-7 years, B = -0.47, p < .001; 8-14 years, B = -0.42, p < .01; 15-20, B = -0.32, p < .05).

CONCLUSIONS

Non-athletes seem to have a higher prevalence of respiratory symptoms. Among former athletes, career characteristics seem to play a crucial role, with special emphasis to its duration, where the most lengthy seem to be more associated with respiratory symptoms.

Special considerations for adolescent athletic and asthmatic patients

Asthma is defined as a chronic inflammatory disorder of the airways with bronchial hyperresponsiveness and variable bronchoconstriction, and is one of the most common diseases in childhood and adolescence. Exercise-induced asthma-like symptoms and asthma are also frequently seen in highly trained athletes. Exercise-induced asthma (EIA) and exercise-induced bronchoconstriction (EIB) are found in 8%–10% of healthy school-aged children and in 35% of children with asthma. Highly increased ventilation, inhalation of cold, dry air and air pollutants (eg, chlorine) are thought to be important triggers for EIA and EIB. EIA is often experienced concurrently with vocal cord dysfunction, which needs to be considered during the differential diagnosis. The pharmacological treatment of EIA is similar to the treatment of asthma in nonexercising adolescents. The therapy is based on anti-inflammatory drugs (eg, inhaled glucocorticosteroids) and bronchodilators (eg, β₂-agonists). The treatment of EIB is comparable to the treatment of EIA and leukotriene modifiers offer a new and promising treatment option, particularly in EIB. Generally, athletes may not use β₂-agonists according to the prohibited list of the World Anti-Doping Agency (WADA). However, the WADA list contains specific β₂-agonistic substances that are permitted to be used by inhalation.

Exercise-induced bronchoconstriction in elite long-distance runners in Brazil

OBJECTIVE

To determine the prevalence of exercise-induced bronchoconstriction among elite long-distance runners in Brazil and whether there is a difference in the training loads among athletes with and without exercise-induced bronchoconstriction.

METHODS

This was a cross-sectional study involving elite long-distance runners with neither current asthma symptoms nor a diagnosis of exercise-induced bronchoconstriction. All of the participants underwent eucapnic voluntary hyperpnea challenge and maximal cardiopulmonary exercise tests, as well as completing questionnaires regarding asthma symptoms and physical activity, in order to monitor their weekly training load.

RESULTS

Among the 86 male athletes recruited, participation in the study was agreed to by 20, of whom 5 (25%) were subsequently diagnosed with exercise-induced bronchoconstriction. There were no differences between the athletes with and without exercise-induced bronchoconstriction regarding anthropometric characteristics, peak oxygen consumption, baseline pulmonary function values, or reported asthma symptoms. The weekly training load was significantly lower among those with exercise-induced bronchoconstriction than among those without.

CONCLUSIONS

In this sample of long-distance runners in Brazil, the prevalence of exercise-induced bronchoconstriction was high.

Pharmacotherapy for exercise-induced asthma: allowing normal levels of activity and sport

Exercise-induced bronchoconstriction (EIB) is experienced by the majority of an estimated 300 million individuals who have asthma, a condition that affects all ages and is increasing globally. Respiratory water loss with dehydration of the airways causing mediator release and airway narrowing is considered the cause of EIB, the severity of which will be increased if the inhaled air is cold or polluted. Adequate control of asthma is essential to minimize or prevent EIB and permit normal levels of physical activity and sport. This is important because exercise is a necessary component of daily living, assists in obtaining and maintaining a healthy body and has been demonstrated to benefit asthmatics. Inhaled glucocorticosteroids and inhaled β(2)-adrenoceptor agonists (IβA) are the pharmacological agents of choice to manage asthma and minimize EIB, assisted when necessary, by other drugs including leukotriene receptor antagonists and chromones. Tolerance from daily use of IβA is of concern and more flexible drug therapy needs to be considered. Optimal use of inhalers to deliver drugs effectively requires closer attention. Pharmacogenetics may hold the key to future drug therapy.

Occurrence of asthma symptoms and of airflow obstruction in amateur swimmers between 8 and 17 years of age

OBJECTIVE

To determine the prevalence of asthma symptoms and of airflow obstruction in amateur swimmers between 8 and 17 years of age, as well as to assess the awareness of asthma and asthma management among these swimmers, their parents, and their coaches.

METHODS

Our sample comprised 1,116 amateur swimmers who completed a modified version of the International Study of Asthma and Allergies in Childhood written questionnaire, to which questions regarding the reasons to initiate swimming and regarding asthma management had been added. In addition, the participants underwent spirometry prior to a swimming competition.

RESULTS

The prevalence of asthma symptoms in the last 12 months was 11.5%, and 327 (29.4%) of the participants reported "wheezing or whistling" in the past. Of the 223 swimmers who reported "asthma ever" or "bronchitis ever", only 102 (45.7%) reported having ever been treated: the most common "treatment" was swimming (in 37.3%), and only 12.7% used inhaled corticosteroids. Of the 254 participants (22.7%) with airflow obstruction, only 52 (20.5%) reported having asthma symptoms.

CONCLUSIONS

Asthma symptoms are present in amateur swimmers, and a considerable number of such swimmers have airflow obstruction without symptoms. It is therefore likely that the prevalence of asthma is underestimated in this population. It is worrisome that, in our study sample, the swimmers previously diagnosed with asthma were not using the recommended treatments for asthma. The clinical implications of these findings underscore the importance of implementing educational measures for amateur swimmers, as well as for their parents and coaches, to help them recognize asthma symptoms and the consequent risks in the sports environment, in order to allow prompt diagnosis and early clinical intervention.

The effect of exposure to chlorine on pulmonary function tests and respiratory and allergic symptoms in Iranian lifeguards

Lifeguards are frequently exposed to various irritant chemicals including chlorine during work, which can induce respiratory and allergic disorders. In this study, pulmonary function tests (PFTs) and self-reported respiratory and allergic symptoms in lifeguards were compared with matched control subjects. The frequency of respiratory and allergic symptoms was evaluated in a sample of 38 Iranian male lifeguards and 38 control subjects with similar age, having other jobs from the general population, using a questionnaire including questions on work-related respiratory and allergic symptoms in the past year, smoking habits, and duration of working as a lifeguard. PFTs were also measured in lifeguard subjects before and 15 min after 200 µg inhaled salbutamol and baseline PFT in controls. A total of 22 (55%) participants reported work-related respiratory symptoms. Sputum (39.4%) and cough (18.4%) were the most common symptoms and only 7.9% and 15.8% of lifeguards reported wheezing and shortness of breath, respectively. Both sputum and breathlessness were significantly higher in lifeguards than control group (p < 0.05 and p < 0.005, respectively). Most allergic symptoms (sneezing and runny nose) in lifeguards were also significantly greater than control group (p < 0.05 for both cases). In addition, all respiratory (except sputum and wheezing) and allergic symptoms were significantly higher in lifeguards during work compared with rest period (p < 0.05 to p < 0.005). Most PFT values were also significantly lower in lifeguards than control subjects (p < 0.05 to p < 0.001). In addition, most (all) PFT values were significantly improved after 200 µg inhaled salbutamol (p < 0.05 to p < 0.001). These results showed that lifeguards have higher frequencies of work related respiratory symptoms and allergic symptoms particularly during the work period. PFT values were also significantly reduced among lifeguards.

Extended diagnostic criteria used for indirect challenge testing in elite asthmatic swimmers

The aim of the study was to investigate the prevalence of asthma with or without exercise induced symptoms among elite and elite aspiring swimmers and to compare sport specific exercise provocation with mannitol provocation.

METHODS

101 adolescent swimmers were investigated with mannitol provocation and sport specific exercise challenge test. Mannitol positivity was defined as either direct FEV(1) PD15 (ordinary criteria) or as β(2)-reversibility ≥15% after challenge (extended criteria). A direct positive exercise test was defined as a drop in FEV(1) of 10% (ordinary criteria) or a difference in FEV of ≥15% either spontaneous, variability, or with β2-agonist, reversibility (extended criteria).

RESULTS

We found a high prevalence of mannitol and/or exercise positivity. Twenty-six swimmers were mannitol direct positive and 14 were direct exercise positive using ordinary criteria. Using extended criteria 43 were mannitol positive and 24 were exercise positive. When including reversibility and variability to define a positive test the sensitivity for current asthma with or without exercise induced symptoms increased while the specificity remained roughly unchanged. Direct positivity for mannitol and exercise poorly overlapped using ordinary criteria but improved using extended criteria.

CONCLUSION

We found a high prevalence of asthma among elite swimmers. The use of variability and reversibility (liability) as additional criteria to define a positive test provided to our mind relevant information and should be considered.

Exercise-induced bronchoconstriction in Tunisian elite athletes is underdiagnosed

Many studies have shown an increased risk of developing exercise-induced bronchoconstriction among the athletic population, particularly at the elite level. Subjective methods for assessing exercise-induced bronchoconstriction such as surveys and questionnaires have been used but have resulted in an underestimation of the prevalence of airway dysfunction when compared with objective measurements. The aim of the present study was to compare the prevalence of exercise-induced bronchoconstriction among Tunisian elite athletes obtained using an objective method with that using a subjective method, and to discuss the possible causes and implications of the observed discrepancy. As the objective method we used spirometry before and after exercise and for the subjective approach we used a medical history questionnaire. All of the recruited 107 elite athletes responded to the questionnaire about respiratory symptoms and medical history and underwent a resting spirometry testing before and after exercise. Post-exercise spirometry revealed the presence of exercise-induced bronchoconstriction in 14 (13%) of the elite athletes, while only 1.8% reported having previously been diagnosed with asthma. In conclusion, our findings indicate that medical history-based diagnoses of exercise-induced bronchoconstriction lead to underestimations of true sufferers.

β₂-Agonists and physical performance: a systematic review and meta-analysis of randomized controlled trials

Inhaled β₂-agonists are commonly used as bronchodilators in the treatment of asthma. Their use in athletes, however, is restricted by anti-doping regulations. Controversies remain as to whether healthy elite athletes who use bronchodilators may gain a competitive advantage. The aim of this systematic review and meta-analysis is to assess the effects of inhaled and systemic β₂-agonists on physical performance in healthy, non-asthmatic subjects. To this end, MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched up to August 2009. Reference lists were searched for additional relevant studies. The search criteria were for randomized controlled trials examining the effect of inhaled or systemic β₂-agonists on physical performance in healthy, non-asthmatic subjects. Two authors independently performed the selection of studies, data extraction and risk of bias assessment. Parallel-group and crossover trials were analysed separately. Mean difference (MD) and 95% confidence intervals were calculated for continuous data and, where possible, data were pooled using a fixed effects model. Twenty-six studies involving 403 participants (age range 7-30 years) compared inhaled β₂-agonists with placebo. No significant effect could be detected for inhaled β₂-agonists on maximal oxygen consumption (VO₂(max)) [MD -0.14 mL · kg⁻¹ · min⁻¹; 95% CI -1.07, 0.78; 16 studies], endurance time to exhaustion at 105-110% VO₂(max) (MD -1.5 s; 95% CI -15.6, 12.6; four studies), 20-km time trial duration (MD -4.4 s; 95% CI -23.5, 14.7; two studies), peak power (MD -0.14 W · kg⁻¹; 95% CI -0.54, 0.27; four studies) and total work during a 30-second Wingate test (MD 0.80 J · kg⁻¹; 95% CI -2.44, 4.05; five studies). Thirteen studies involving 172 participants (age range 7-22 years) compared systemic β₂-agonists with placebo, with 12 studies involving oral and one study involving intravenous salbutamol. A significant effect was detected for systemic β₂-agonists on endurance time to exhaustion at 80-85% VO₂(max) (MD 402 s; 95% CI 34, 770; two studies), but not for VO₂(max) (placebo 42.5 ± 1.7 mL · kg⁻¹ · min⁻¹, salbutamol 42.1 ± 2.9 mL · kg⁻¹ · min⁻¹, one study), endurance time to exhaustion at 70% VO₂(max) (MD 400 s; 95% CI -408, 1208; one study) or power output at 90% VO₂(max) (placebo 234.9 ± 16 W, salbutamol 235.5 ± 18.1 W, one study). A significant effect was shown for systemic β₂-agonists on peak power (MD 0.91 W · kg⁻¹; 95% CI 0.25, 1.57; four studies), but not on total work (MD 7.8 J · kg⁻¹; 95% CI -3.3, 18.9; four studies) during a 30-second Wingate test. There were no randomized controlled trials assessing the effects of systemic formoterol, salmeterol or terbutaline on physical performance. In conclusion, no significant effects were detected for inhaled β₂-agonists on endurance, strength or sprint performance in healthy athletes. There is some evidence indicating that systemic β₂-agonists may have a positive effect on physical performance in healthy subjects, but the evidence base is weak.

Self-reported asthma and allergies in top athletes compared to the general population - results of the German part of the GA2LEN-Olympic study 2008

Background

Prevalence of asthma and allergies in top athletes is high. However, most previous studies did not include a general population comparison group. We aimed to compare the prevalence of asthma, allergies and medical treatment in different groups of German top athletes to the general population.

Methods

Prior to the 2008 Summer Olympic Games, 291 German candidates for participation (65%) completed a questionnaire on respiratory and allergic symptoms. Results were compared to those of a general population study in Germany (n = 2425, response 68%). Furthermore, associations between types of sports and the self-reported outcomes were calculated. All models were adjusted for age, sex, level of education and smoking.

Results

Athletes reported significantly more doctors' diagnosed asthma (17% vs. 7%), more current use of asthma medication (10% vs. 4%) and allergic rhinitis (25% vs. 17%) compared to the general population. After adjustment, top athletes only had an increased Odds Ratio for doctor's diagnosed asthma (OR: 1.6; 95% CI 1.1-2.5). Compared to the general population, athletes in endurance sports had an increased OR for doctor's diagnosed asthma (2.4; 1.5-3.8) and current use of asthma medication (1.8; 1.0-3.4). In this group, current wheeze was increased when use of asthma medication was taken into account (1.8; 1.1-2.8). For other groups of athletes, no significantly increased ORs were observed.

Conclusions

Compared to the general population, an increased risk of asthma diagnosis and treatment was shown for athletes involved in endurance sports. This might be due to a better medical surveillance and treatment of these athletes.

Physical Activity in Childhood Asthma: Friend or Foe?

Physical activity has been considered as a double-edged sword for children with asthma. Children with asthma are recommended to participate in physical activities like their healthy nonasthmatic peers because regular physical activity positively affects psychological functioning, quality of life, morbidity, and aerobic fitness in children with asthma. However, uncontrolled asthma with ongoing exercise-induced bronchoconstriction may limit participation in sports, free play, and daily living. Observations also suggest that high-intensity exercise performed in cold air, seasonal allergens, pollutants, or respiratory virus infections may increase the risk for asthma in the highly active child. In contrast, a sedentary lifestyle has been highlighted as the explanation for the increased prevalence of asthma in the past decades. However, there is no consensus on whether a low level of physical activity increases the severity or risk of asthma. Use of asthma medications and good asthma control can make the conditions favorable for a physically active lifestyle and influence physical activity level and the level of aerobic fitness.

Effects of acute salbutamol inhalation on quadriceps force and fatigability

INTRODUCTION

Oral beta2-agonist administration improves muscle function in persons without asthma. We performed a double-blind, randomized, controlled crossover study to assess whether acute inhaled salbutamol administration improves muscle strength and fatigability in healthy moderately trained subjects.

METHODS

Quadriceps muscle strength was measured during maximal voluntary contraction (MVC) and femoral nerve magnetic stimulation (potentiated single twitch, TwQpeak) before and after (i) a maximal incremental cycling test (n = 10) and (ii) 50 maximal isometric one-leg extensions (n = 9). Each exercise test was performed on three occasions, after salbutamol (200 and 800 microg) or placebo inhalation.

RESULTS

Before exercise, treatments had no significant effect on MVC [(placebo) 597 +/- 146 N vs (200 microg) 629 +/- 151 N vs (800 microg) 610 +/- 148 N] and TwQpeak [(placebo) 215 +/- 83 N vs (200 microg) 227 +/- 69 N vs (800 microg) 250 +/- 84 N]. Maximal power during cycling and maximal force during leg extensions did not differ between treatments. Treatments had no effect on MVC and TwQpeak reductions at 30 min [MVC: (placebo) -8 +/- 9% vs (200 microg) -9 +/- 7% vs (800 microg) -8 +/- 5%; TwQpeak: (placebo) -29 +/- 13% vs (200 microg) -23 +/- 15% vs (800 microg) -20 +/- 8%] and 60 min [MVC: (placebo) -12 +/- 17% vs (200 microg) -6 +/- 9% vs (800 microg) -8 +/- 8%; TwQpeak: (placebo) -20 +/- 21% vs (200 microg) -19 +/- 23% vs (800 microg) -8 +/- 7%] after cycling. Similarly, reductions in MVC and TwQpeak were not significantly different between treatments at 30 [MVC: (placebo) -11 +/- 9% vs (200 microg) -12 +/- 7% vs (800 microg) -8+/- 16%; TwQpeak: (placebo) -37 +/- 12% vs (200 microg) -33 +/- 20% vs (800 microg) -32 +/- 16%] and 60 min [MVC: (placebo) -10 +/- 11% vs (200microg) -11 +/- 6% vs (800 microg) -8 +/- 20%; TwQpeak: (placebo) -30 +/- 11% vs (200 microg) -28 +/- 24% vs (800 microg) -27 +/- 15%] after leg extensions. Treatments did not modify maximal voluntary activation at any time of the protocol.

CONCLUSION

Acute therapeutic or supratherapeutic doses of inhaled salbutamol have no effect on quadriceps strength, fatigue, and recovery in men without asthma.

Ergogenic effects of inhaled beta2-agonists in non-asthmatic athletes

The potential ergogenic effects of asthma medication in athletes have been controversially discussed for decades. The prevalence of asthma is higher in elite athletes than in the general population. The highest risk for developing asthmatic symptoms is found in endurance athletes and swimmers. In addition, asthma seems to be more common in winter-sport athletes. Asthmatic athletes commonly use inhaled beta2-agonists to prevent and treat asthmatic symptoms. However, beta2-agonists are prohibited according to the "Prohibited List of the World Anti-Doping Agency" (WADA). Until the end of 2009 an exception was only allowed for the substances formoterol, salbutamol, salmeterol, and terbutaline by inhalation, as long as a so-called therapeutic use exemption has been applied for and was granted by the relevant anti-doping authorities. From 2010 salbutamol and salmeterol are allowed by inhalation requiring a so called declaration of use.

Chronic exercise reduces illness severity, decreases viral load, and results in greater anti-inflammatory effects than acute exercise during influenza infection

BACKGROUND

It is assumed that moderate exercise may improve resistance to infection and reduce inflammation, but there are limited data to support this assumption in an infection model.

METHODS

BALB/cJ mice were assigned to the following groups: no exercise (NON-EX), 1 session of acute exercise (A-EX), or chronic exercise for approximately 3.5 months (C-EX). Mice were infected with influenza (C-EX mice infected at rest; A-EX mice infected 15 min after exercise).

RESULTS

C-EX mice demonstrated the lowest severity of infection, assessed by body weight loss and food intake. There was less virus in the lungs at day 5 after infection in C-EX and A-EX mice compared with NON-EX mice (P = .02) and less virus at day 2 after infection only in C-EX mice (P = .07). Soon after infection (day 2), interleukin 6 (IL-6), monocyte chemoattractant protein 1 (MCP-1), macrophage inflammatory protein 1beta, and tumor necrosis factor alpha in the bronchoalveolar lavage (BAL) fluid were lower in C-EX and A-EX than in NON-EX mice. At day 5 after infection, the BAL fluid from C-EX (but not A-EX) mice had less IL-6, interleukin 12p40, granulocyte colony-stimulating factor, keratinococyte-derived chemokine, and MCP-1 than that from NON-EX mice. A trend toward reduced immunopathologic response was found in C-EX mice.

CONCLUSIONS

Chronic exercise resulted in reduced symptoms, virus load, and levels of inflammatory cytokine and chemokines. Acute exercise also showed some benefit, which was limited to the early phase of infection.

National Athletic Trainers' Association position statement: environmental cold injuries

OBJECTIVE

To present recommendations for the prevention, recognition, and treatment of environmental cold injuries.

BACKGROUND

Individuals engaged in sport-related or work-related physical activity in cold, wet, or windy conditions are at risk for environmental cold injuries. An understanding of the physiology and pathophysiology, risk management, recognition, and immediate care of environmental cold injuries is an essential skill for certified athletic trainers and other health care providers working with individuals at risk.

RECOMMENDATIONS

These recommendations are intended to provide certified athletic trainers and others participating in athletic health care with the specific knowledge and problem-solving skills needed to address environmental cold injuries. Each recommendation has been graded (A, B, or C) according to the Strength of Recommendation Taxonomy criterion scale.

Exercise-induced bronchoconstriction and atopy in Tunisian athletes

Background

This study is a cross sectional analysis, aiming to evaluate if atopy is as a risk factor for exercise induced bronchoconstriction (EIB) among Tunisian athletes.

Methods

Atopy was defined by a skin prick test result and EIB was defined as a decrease of at least 15% in forced expiratory volume in one second (FEV1) after 8-min running at 80–85% HRmaxTheo. The study population was composed of 326 athletes (age: 20.8 ± 2.7 yrs – mean ± SD; 138 women and 188 men) of whom 107 were elite athletes.

Results

Atopy was found in 26.9% (88/326) of the athletes. Post exercise spirometry revealed the presence of EIB in 9.8% of the athletes including 13% of the elite athletes. Frequency of atopy in athletes with EIB was significantly higher than in athletes without EIB [62.5% vs 23.1%, respectively].

Conclusion

This study showed that atopic Tunisian athletes presented a higher risk of developing exercise induced bronchoconstriction than non-atopic athletes.

Asthma and the elite athlete: summary of the International Olympic Committee's consensus conference, Lausanne, Switzerland, January 22-24, 2008

Respiratory symptoms cannot be relied on to make a diagnosis of asthma and/or airways hyperresponsiveness (AHR) in elite athletes. For this reason, the diagnosis should be confirmed with bronchial provocation tests. Asthma management in elite athletes should follow established treatment guidelines (eg, Global Initiative for Asthma) and should include education, an individually tailored treatment plan, minimization of aggravating environmental factors, and appropriate drug therapy that must meet the requirements of the World Anti-Doping Agency. Asthma control can usually be achieved with inhaled corticosteroids and inhaled beta(2)-agonists to minimize exercise-induced bronchoconstriction and to treat intermittent symptoms. The rapid development of tachyphylaxis to beta(2)-agonists after regular daily use poses a dilemma for athletes. Long-term intense endurance training, particularly in unfavorable environmental conditions, appears to be associated with an increased risk of developing asthma and AHR in elite athletes. Globally, the prevalence of asthma, exercise-induced bronchoconstriction, and AHR in Olympic athletes reflects the known prevalence of asthma symptoms in each country. The policy of requiring Olympic athletes to demonstrate the presence of asthma, exercise-induced bronchoconstriction, or AHR to be approved to inhale beta(2)-agonists will continue.

Pharmaceutical treatment of asthma symptoms in elite athletes - doping or therapy?

Asthma, exercise-induced bronchoconstriction, and airway hyper-responsiveness are often found in elite athletes, perhaps as a consequence of their sport or maybe because asthma is a common disorder in young adults. Inhaled beta2-agonists (IBA) are frequently used in elite athletes, but due to regulations introduced by the International Olympic Committee, the use of anti-asthmatic therapy might change. Drugs that make ergogenic effect persist are prohibited in all athletes, whether or not they take part in competitions and systemic steroids and beta2-agonists are among such drugs. On the other hand, opinion is more divided about the use of inhaled corticosteroids (ICS) and IBA. In humans, no effect has been found on the oxygen uptake, performance or distance run with therapeutic doses of IBA, either in asthmatics or non-asthmatics, whereas others report an ergogenic effect and better lung function of high doses of a beta2-agonist in non-asthmatics. Anti-asthmatic treatment is necessary for asthmatics, but should not be used by non-asthmatic elite athletes due to both possible systemic effects and furthermore, side effects of both ICS and IBA.

Exercise-induced bronchoconstriction in athletes-should we screen?

The fact that exercise-induced bronchoconstriction (EIB) may be both over- and underdiagnosed in athletes has led to calls for widespread screening for the condition. This article assesses such a strategy by employing the standard framework used when evaluating any screening policy. This approach highlights a number of concerns and allows recommendations to help optimize the success of such a strategy if it were to be implemented.

Do inhaled beta(2)-agonists have an ergogenic potential in non-asthmatic competitive athletes?

The prevalence of asthma is higher in elite athletes than in the general population. The risk of developing asthmatic symptoms is the highest in endurance athletes and swimmers. Asthma seems particularly widespread in winter-sport athletes such as cross-country skiers. Asthmatic athletes commonly use inhaled beta(2)-agonists to prevent and treat asthmatic symptoms. However, beta(2)-agonists are prohibited according to the Prohibited List of the World Anti-Doping Agency. An exception can be made only for the substances formoterol, salbutamol, salmeterol and terbutaline by inhalation, as long as a therapeutic use exemption has been applied for and granted. In this context, the question arises of whether beta(2)-agonists have ergogenic benefits justifying the prohibition of these substances. In 17 of 19 randomised placebo-controlled trials in non-asthmatic competitive athletes, performance-enhancing effects of the inhaled beta(2)-agonists formoterol, salbutamol, salmeterol and terbutaline could not be proved. This is particularly true for endurance performance, anaerobic power and strength performance. In three of four studies, even supratherapeutic doses of salbutamol (800-1200 microg) had no ergogenic effect. In contrast to inhaled beta(2)-agonists, oral administration of salbutamol seems to be able to improve the muscle strength and the endurance performance. There appears to be no justification to prohibit inhaled beta(2)-agonists from the point of view of the ergogenic effects.

Allergy in marathon runners and effect of Lactobacillus GG supplementation on allergic inflammatory markers

OBJECTIVE

We studied the prevalence of asthma and allergy in non-elite marathon runners and investigated the effects of probiotic supplementation on allergic inflammatory markers.

METHODS

Asthma and allergies were surveyed by questionnaire, and blood eosinophils, serum eosinophil cationic protein (ECP), total IgE, and Phadiatop were measured in 141 Finnish marathon runners who took part in the Helsinki City Marathon. They were also randomized to receive either Lactobacillus GG (LGG) or placebo during the 3 months of the pollen season prior to the marathon.

RESULTS

Lifetime prevalence of physician-diagnosed asthma was 4.3% (six out of 139 athletes), of allergic rhinitis 17.3% (24/139), of food allergy 5.0% (7/139), and of atopic eczema 4.3% (6/139). Prevalence of atopy was 31% (35/112), and 21% (24/112) of the athletes were sensitized to birch pollen. Asthma or allergy medication was used by 20% (28/139) of the athletes. During pollen season, serum ECP increased significantly in all athletes, and total IgE and Phadiatop in atopics. The marathon induced a significant eosinopenia but had no effect on serum ECP or total IgE. No differences in changes were seen between groups receiving LGG or placebo.

CONCLUSION

Non-elite marathon runners have asthma and allergies similar to Finnish general population. LGG supplementation did not prevent the increase of allergic markers during the pollen season, or the eosinopenia induced by the marathon.

Inhaled beta2 agonists and performance in competitive athletes

OBJECTIVES

To provide an overview of the current literature on the use of inhaled beta2 agonists in non-asthmatic competitive athletes, and to assess the performance enhancing effect of inhaled beta2 agonists.

METHODS

Review of the literature.

RESULTS

Twenty randomised, placebo controlled studies (19 double blind, one single blind) were located. Only three studies reported a performance enhancing effect of inhaled beta2 agonists. However, methodological shortcomings were most likely responsible for these findings (for example, non-elite athletes, inconsistent results in different tests, subgroups with above-average responsiveness).

CONCLUSIONS

This review reveals that there is no ergogenic potential of inhaled beta2 agonists in non-asthmatic athletes. In view of the epidemiology of asthma in athletes and the considerable workload involved in provision of therapeutic use exemptions the inclusion of inhaled beta2 agonists on the list of prohibited substances should be reconsidered.

Exhaled nitric oxide in single and repetitive prolonged exercise

This study was performed to determine the influence of single and repetitive exercise on nitric oxide (NO) concentration in the lung. Exhaled NO concentration (FE(NO)) was measured during a constant-flow exhalation manoeuvre (170 ml x s(-1), against a 10 cmH2O resistance) in healthy individuals (a) during and after a 100-min square-wave exercise of between 25 and 60% of maximal power output (n = 18) and (b) before and after five successive prolonged exercises (90-120 min, 75-85% of maximal heart rate) separated by 48 or 24 h (n = 8). The FE(NO0.170) was decreased during and after the 100-min exercise test (mean +/- s(x): 58.5 +/- 3.7% and 76.7 +/- 5.2% of resting value at 90 min of exercise and 15 min post-exercise, respectively; P < 0.05). The five successive exercise sessions induced a similar post-exercise FE(NO0.170) decrement (73.1 +/- 2.9% of resting value 15 min post-exercise), while basal FE(NO0.170) values were not different between the five sessions (P > 0.05). These results suggest that prolonged exercise induces a reduction in NO concentration within the lung that lasts for several minutes after the end of exercise. However, repetitive exercises (at least every 24 h) allow complete NO recovery from one session to another. The implication of such a decrease in NO availability within the lung remains to be clarified.

The effect of a competitive season and environmental factors on pulmonary function and aerobic power in varsity hockey players

This study examined the effect of a competitive season and environmental factors on pulmonary function and aerobic power in varsity hockey players. Fourteen male subjects completed testing before and after a 7-month varsity hockey season within ice arena conditions. All subjects completed an aerobic power [Formula: see text]O2 max test on a cycle ergometer. Pulmonary function tests were performed at rest and 1, 10, 15, and 25 min after the [Formula: see text]O2 max test. The arena environment was monitored during testing and throughout the season for temperature, relative humidity, gaseous chemicals, moulds, and fungi. There was no change in [Formula: see text]O2 max during the season. The percent change in forced expiratory flow in 1 s (FEV1) post-exercise compared to resting FEV1 and forced vital capacity (FVC) after the [Formula: see text]O2 max test were significantly lower after the season. The arena temperature and relative humidity ranged between 13 and 16 °C and between 30% and 45% over the course of the season. Sulfur dioxide (0.7-4.5 ppm) was found in the arena and no airborne moulds unique to the dressing room environment were found to exceed Health Canada's guideline of 50 CFU/m3 for indoor air quality. It was concluded that some hockey players experience limitations to pulmonary function over the course of a competitive season. Key words: exercise-induced bronchospasm, exercise-induced hypoxaemia, air quality, mould, asthma.

Exercise-induced bronchospasm among healthy elite cross country skiers and non-athletic students

Regular exercise in cold, dry air is believed to be a predisposing factor for exercise-induced bronchospasm (EIB). The aim of this study was to compare the occurrence of EIB among previously healthy elite cross country skiers and their non-athletic control subjects. Twenty healthy elite cross country skiers and 18 non-asthmatic controls were challenged by a standardized free exercise test. Thereafter, subjects' respiratory function was followed by flow-volume spirometry up to 30 min. EIB was defined in the post-exercise spirometry as at least one of the following: a >or=10% decrease in forced expiratory volume in 1 s (FEV1), a >or=20% decrease in mean maximal expiratory flow (MMEF) or a >or=25% decrease in peak expiratory flow rate (PEF). EIB was found in two skiers and one control according to FEV1, for seven skiers and two controls according to MMEF. Two skiers and one control had exercise-induced asthma (EIA) according to both parameters. The largest decrease in PEF was 13%, that did not result in additional diagnoses. All nine of the subjects with a positive test result reported asthma-like symptoms (dyspnea, cough or increased mucus excretion) after the exercise challenge. Accordingly, seven previously healthy skiers (35%) and two controls (11%) were diagnosed as having EIB. In addition, three skiers of the original cohort were excluded because of an earlier asthma diagnosis, making the total asthma prevalence 10/23 (42%) among the elite skiers. It was concluded that EIB is more common in elite cross country skiers than in non-athletic controls. The bronchoconstriction induced by exercise is usually mild or moderate, and flow-volume spirometry with sensitive flow parameters is needed for it to be diagnosed. Even a mild asthma decreases minute ventilation and maximal performance of winter sport athletes. Therefore, skiers with long-term respiratory symptoms or decreased performance should be studied for EIA and treated adequately.

Exercise immunology: the current state of man and mouse

The mechanisms governing the body's response to physical exercise have been investigated from various perspectives including metabolism, nutrition, age and sex. Increased attention to the immune system during recent decades is reflected by a rapidly growing number of publications in the field. This article highlights the most recent findings and only briefly summarises more basic concepts already reviewed by others. Topics include Th1/Th2 cytokine balance, inoculation time, age and immune compensation. Some less investigated areas are discussed including studies in children, the environment and dendritic cells. Because physical exercise enhances some aspects and suppresses other aspects of immunity, the biological significance of alterations in the immune system are unknown. So far, no link between immunological alterations and infection rate has been established and infection after strenuous physical exercise is equally likely to be the result of exercising with an already established rather than a new infection. If there is an increased risk for infections with increased exercise duration and intensity, why do overtrained athletes not display the greatest risk for upper respiratory tract infections? Increased knowledge on immune system modulations with physical exercise is relevant both from a public health and elite athlete's point of view.

Activity-induced asthma

Exercise is the most common trigger of persistent childhood asthma. The history for EIA can be complicated by the lack of perception of significant airway obstruction during exercise. One must carefully identify those children with EIA from the group of children who report low level of activity because of lack of interest or because they are out of shape. Baseline spirometry of children with persistent asthma is frequently normal. Spirometry is important to identify those children with EIA who underrecognize their disease, but normal results should not be used as evidence of absence of disease. Formal exercise testing should be considered when the diagnosis is unclear or if there seems to be a lack of bronchoprotection with inhaled albuterol. The goal of treatment of EIA should be the attainment of a normal activity level for children and adolescents. Identification of the limits imposed by EIA and establishment of goals of therapy with the child and family should be the initial action. Inactivity or reduced exertion, in the presence of this diagnosis. should not be accepted. Therapy for EIA starts with control of the underlying persistent asthma. Inhaled corticosteroids are the most effective initial treatment of both EIA and persistent asthma in children and adolescents. Exercise-induced asthma is a common aspect of a prevalent disease that warrants proper diagnosis and treatment. With appropriate therapy, children with EIA should be able to participate in sports and maintain normal activity. They should strive to compete in the same playing field as their peers and have the same goals as those children and athletes who do not have exercise-induced asthma.

Mannitol as a challenge test to identify exercise-induced bronchoconstriction in elite athletes

Bronchial provocation tests provide objective criteria for asthma and exercise-induced bronchoconstriction (EIB) and were recommended to justify the use of inhaled beta2-agonists by athletes at the Winter Olympics 2002. Eucapnic voluntary hyperpnea (EVH) was one test recommended to identify EIB. Provocation with EVH requires a special dry gas mixture limiting its availability. Provocation tests with osmotic aerosols require less expensive equipment that is easily portable. We assessed the sensitivity of a challenge with mannitol to identify responsiveness to EVH in 50 elite summer sport athletes who were unselected if they had respiratory symptoms. Asthma was previously diagnosed by a doctor in 27 subjects, and 21 subjects were currently under treatment for EIB or asthma. The mean predicted FEV1 was 103.6 +/- 10.8%, FVC was 99 +/- 13.3%, and mean forced expiratory flow during the middle half of the FVC was 104 +/- 22.7%. A total of 25 subjects were positive to EVH challenge (mean percentage of fall in FEV1 was 25.4 +/- 15% SD), and 26 subjects had a positive mannitol challenge (geometric mean [95% confidence interval] provoking dose causing a 10% fall in forced expiratory volume in one second [PD10] was 202 mg [134, 300], with 24 of the subjects positive to both challenges). Mannitol had a sensitivity of 96% and specificity of 92% to identify a positive response to EVH and, as such, could be used as an alternative to EVH to identify EIB.