Swimming and asthma: factors underlying respiratory symptoms in competitive swimmers

Prevalence of lower airway dysfunction in athletes: a systematic review and meta-analysis by a subgroup of the IOC consensus group on 'acute respiratory illness in the athlete'

OBJECTIVE

To report the prevalence of lower airway dysfunction in athletes and highlight risk factors and susceptible groups.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, EBSCOhost and Web of Science (1 January 1990 to 31 July 2020).

ELIGIBILITY CRITERIA

Original full-text studies, including male or female athletes/physically active individuals/military personnel (aged 15-65 years) who had a prior asthma diagnosis and/or underwent screening for lower airway dysfunction via self-report (ie, patient recall or questionnaires) or objective testing (ie, direct or indirect bronchial provocation challenge).

RESULTS

In total, 1284 studies were identified. Of these, 64 studies (n=37 643 athletes) from over 21 countries (81.3% European and North America) were included. The prevalence of lower airway dysfunction was 21.8% (95% CI 18.8% to 25.0%) and has remained stable over the past 30 years. The highest prevalence was observed in elite endurance athletes at 25.1% (95% CI 20.0% to 30.5%) (Q=293, I²=91%), those participating in aquatic (39.9%) (95% CI 23.4% to 57.1%) and winter-based sports (29.5%) (95% CI 22.5% to 36.8%). In studies that employed objective testing, the highest prevalence was observed in studies using direct bronchial provocation (32.8%) (95% CI 19.3% to 47.2%). A high degree of heterogeneity was observed between studies (I²=98%).

CONCLUSION

Lower airway dysfunction affects approximately one in five athletes, with the highest prevalence observed in those participating in elite endurance, aquatic and winter-based sporting disciplines. Further longitudinal, multicentre studies addressing causality (ie, training status/dose-response relationship) and evaluating preventative strategies to mitigate against the development of lower airway dysfunction remain an important priority for future research.

Association of blood trihalomethane concentrations with asthma in U.S. adolescents: nationally representative cross-sectional study

Background

Population studies show that the use of swimming pools is associated with the risk of asthma and allergic diseases among children. Our objective was to explore the associations between blood trihalomethane (THM) concentrations and asthma among US adolescents, and assess to what extent the association is modified by active tobacco smoke exposure.

Methods

We included 2359 adolescents aged 12–19 years with measured blood concentrations of chloroform (trichloromethane (TCM)), bromodichloromethane (BDCM), dibromochloromethane (DBCM) and bromoform (tribromomethane (TBM)) from the National Health and Nutrition Examination Survey 2005–2012. Logistic regression models were fitted to assess the odds ratios for the association of blood THM concentrations (three or four categories) with the risk of self-reported current and ever (lifetime) asthma.

Results

Blood DBCM concentrations were associated with a higher risk of ever asthma among all adolescents (OR 1.54 (95% CI 1.07–2.21), comparing the extreme exposure categories). The relationship was stronger among adolescents exposed to tobacco smoke (OR 3.96 (95% CI 1.89–8.30), comparing the extreme exposure categories). We also found positive relationships between blood brominated THM concentrations (sum of BDCM, DBCM and TBM) and risk of ever asthma and between blood DBCM and brominated THM concentrations and risk of current asthma among adolescents with tobacco smoke exposure. The relative excess risk of ever asthma due to the interaction between high blood DBCM and brominated THM concentrations and tobacco smoke exposure was 1.87 (95% CI 0.30–3.43) and 0.78 (95% CI 0.07–1.49), respectively.

Conclusions

Exposure to THMs is associated with a higher risk of asthma in adolescents, particularly among those exposed to tobacco smoke.

Among a representative sample of 2359 US adolescents, we found that exposure to THMs was associated with a greater risk of asthma, particularly among those who were co-exposed to tobacco smokehttps://bit.ly/3mpHxgq

Asthma, allergies and respiratory symptoms in different activity groups of swimmers exercising in swimming halls

BACKGROUND

Respiratory symptoms are common in competitive swimmers. However, among these and in swimmers at other activity levels the swimming distance, the total spent time in swimming halls and their medical background varies. Our objectives were, first, to assess their medical histories and the associations with respiratory symptoms among swimmers in different activity groups and then second, to study the pulmonary function findings and related medications in competitive swimmers who exercise in swimming hall environments the most.

METHODS

First, 1118 participants consisting of 133 competitive-, 734 fitness- and 251 occasional swimmers answered questionnaires concerning their medical background, their respiratory symptoms in connection to swimming distance and their amount of time spent in swimming halls. Secondly, in 130 competitive swimmers, pulmonary function was tested by spirometry and a specific questionnaire was used to assess respiratory symptoms, medical histories and prescribed medication.

RESULTS

Respiratory symptoms were reported by 18% of the studied swimmers. Competitive swimmers had significantly more symptoms than fitness- and occasional swimmers. Naturally competitive swimmers swum more than 2000 m and stayed by the pool more than 90 min, longer than the other activity groups of swimmers. Spirometry testing showed airway obstruction in 15 swimmers, which was 12% of the 130 competitive swimmers. 21 of them, had physician-diagnosed asthma and 16 of these individuals had prescribed medication for it.

CONCLUSIONS

Competitive swimmers had the highest swimming hall exposure and reported significantly more respiratory symptoms. A high prevalence of airway obstruction findings in competitive swimmers with asthma and allergies suggests a need for future recommendations for regular testing and special medical care for competitive swimmers.

Swimming-induced changes in pulmonary function: special observations for clinical testing

Background

A special improvement in pulmonary function is found in swimmers. In clinical testing the airway reactivity is observed at certain exercise intensity and target ventilation. However, in highly trained swimmers exercising in water the reactions may not function the same way. The aim was to study the combined effects of the water environment and swimming on pulmonary function and the associations with perceived symptoms.

Methods

First, 412 competitive swimmers completed questionnaires concerning respiratory symptoms at different swimming intensities. Then, pulmonary function testing was performed in 14 healthy elite swimmers. Spirometry and maximal voluntary ventilation (MVV) were measured on land and in water before and after swimming. While swimming, minute ventilation (VE) tidal volume (VT) and breathing frequency (fb) were measured during competition speed swimming.

Results

Swimmers reported the most symptoms at competition speed intensity swimming. In the transition from the land into the water swimming body position, the ratio of forced expiratory volume in one second (FEV₁) and forced expiratory capacity (FVC) (FEV₁/FVC) decreased by a mean (SD) 5.3% (3) in females and by 2.2% (5) in males. During competition speed intensity swimming, the minute ventilation (VE) had a mean of 72 and 75% of calculated maximal voluntary ventilation (cMVV) in females and in males, respectively.

Conclusions

Spirometry showed sex differences in water compared to land measurements. These differences should be considered when the effects of swimming are observed. During the intensity that triggered the symptoms the most, the VE was approximately 20% higher than the target ventilations for clinical testing. These findings encourages specific modifications of clinical testing protocols for elite swimmers.

Inorganic chloramines: a critical review of the toxicological and epidemiological evidence as a basis for occupational exposure limit setting

Inorganic chloramines are not commercially available, but monochloramine is produced in situ for disinfection or for use in chemical synthesis. Inorganic chloramines are also formed when free chlorine reacts with nitrogen containing substances, e.g. ammonia and urea, present in chlorinated water sources. Occupational exposure may, therefore, occur in e.g. swimming pool facilities and the food processing industry. Monochloramine is soluble and stable in water and the dominating inorganic chloramine in chlorinated water sources. No clinical effects were seen in healthy volunteers given monochloramine in drinking water during 4 or 12 weeks in doses of 0.043 or 0.034 mg/kg bw/day, respectively. Limited data indicate that monochloramine is weakly mutagenic in vitro but not genotoxic in vivo. One drinking water study indicated equivocal evidence of carcinogenicity in female rats but not in male rats and mice. No reproductive or developmental effects were shown in rodents in the few studies located. Dichloramine is soluble but unstable in water. In the only study located, mild histological effects in kidneys, thyroid and gastric cardia were observed in rats administered dichloramine in drinking water for 13 weeks. Trichloramine is immiscible with water and evaporates easily from water into air. Therefore, the primary exposure route of concern in the occupational setting is inhalation. Occupational exposure to trichloramine has been demonstrated in indoor swimming pool facilities and in the food processing industry where chlorinated water is used for disinfection. Exposure-response relationships between airborne levels and self-reported ocular and upper airway irritation have been shown in several studies. Exposure to trichloramine may aggravate asthma symptoms in individuals with existing asthma. The risk of developing asthma following long-term exposure to trichloramine cannot be evaluated at present. No data on genotoxic, carcinogenic, reproductive or developmental effects were located. The toxicological data for mono- and dichloramine are insufficient to recommend health-based occupational exposure limits (OELs).As regard trichloramine, the critical effect is judged to be irritation observed in several studies on pool workers, starting at approximately 0.4 mg/m³ (stationary sampling). Based on these data, a health-based OEL of 0.1 mg/m³ (8-h time-weighted average) is recommended. This corresponds to 0.2 mg/m³ for stationary measurements in swimming pool facilities. No short-term exposure limit (STEL) is recommended.

Covariation amongst pool management, trichloramine exposure and asthma for swimmers in Norway

The association between asthma and exposure to the air in swimming facilities has been acknowledged. However, the variation in, long-term exposure to and management of the respiratory irritant trichloramine (NCl₃) is not well understood. In this study, 313 swimmers above 18 years of age licensed by the Norwegian Swimming Association answered a questionnaire about health and swimming. The prevalence of asthma amongst the most-exposed swimmers was 36%. Two facilities, those with the highest and lowest reported prevalence of asthma, were chosen for further investigation. For each facility, a one-week-long monitoring campaign was performed, during which pool management, air and water quality were investigated. The results of this study showed that time of day, occupancy and pool management affect the concentration of NCl₃, which ranged from 58 μg/m³ to 461 μg/m³. Furthermore, in one of the facilities, the concentration of CO₂ was measured to evaluate whether this contaminant could be used to predict the number of pool occupants as well as the concentration of NCl₃ in the air. The concentration of CO₂ was significantly correlated with occupancy level (ρ = 0.82, p = 0.01) and NCl₃ concentration (r = 0.80, p = 0.01). Furthermore, according to the random intercept model the concentration of CO₂ explained 52% of the variation observed in the air concentration of NCl₃. CO₂ sensors to control the air supply can help reduce the air concentrations of NCl₃ and balance the air supply based on occupancy level.

Exhaled nitric oxide as a marker of chlorine exposure in young asthmatic swimmers

BACKGROUND

Swimming is recommended for people with asthma. However, the inevitable exposure to chlorine and its disinfectant byproducts in indoor swimming pools could be responsible for bronchial inflammation and asthma development. Fractional exhaled nitric oxide (FeNO) is a noninvasive marker of airway inflammation that predicts asthma exacerbations.

OBJECTIVES

To evaluate pretraining and posttraining FeNO levels in young swimmers with asthma attending an indoor chlorinated pool compared with a set of healthy swimmers and to examine the potential risk of exposure to chlorine as a factor associated with bronchial inflammation.

METHODS

A total of 146 children (8-18 years old) constantly attending an indoor chlorinated swimming pool were enrolled. Spirometry and FeNO measurements were performed 30 minutes after their arrival at the pool and immediately after exercise. Pre-exercise and postexercise spirometric and FeNO levels were assessed in a random subgroup of 14 swimmers (10 with asthma and 4 without) who performed cardiopulmonary exercise testing.

RESULTS

Asthma was detected in 23 swimmers. In swimmers with asthma, preswimming FeNO values were significantly elevated compared with swimmers without asthma and their FeNO values measured before cardiopulmonary exercise testing. Postexercise FeNO values were significantly decreased by approximately one-third in healthy children and children with asthma in all sporting backgrounds. However, postswimming FeNO values remained significantly higher in swimmers with asthma compared with those without asthma. Forced expiratory volume in 1 second (FEV₁), forced vital capacity (FVC), and FEV₁/FVC ratio values showed no significant difference before and after 2 types of activity.

CONCLUSION

Elevated FeNO levels before and after swimming were recorded in swimmers with asthma not observed in a different exercise field. The presence of chlorine in the indoor swimming pool seems to explain this finding.

Exercise-Induced Bronchoconstriction and the Air We Breathe

An association between airway dysfunction and airborne pollutant inhalation exists. Volatilized airborne fluorocarbons in ski wax rooms, particulate matter, and trichloromines in indoor environments are suspect to high prevalence of exercise-induced bronchoconstriction and new-onset asthma in athletes competing in cross-country skiing, ice rink sports, and swimming. Ozone is implicated in acute decreases in lung function and the development of new-onset asthma from exposure during exercise. Mechanisms and genetic links are proposed for pollution-related new-onset asthma. Oxidative stress from airborne pollutant inhalation is a common thread to progression of airway damage. Key pollutants and mechanisms for each are discussed.

Air quality and temperature effects on exercise-induced bronchoconstriction

Exercise-induced bronchoconstriction (EIB) is exaggerated constriction of the airways usually soon after cessation of exercise. This is most often a response to airway dehydration in the presence of airway inflammation in a person with a responsive bronchial smooth muscle. Severity is related to water content of inspired air and level of ventilation achieved and sustained. Repetitive hyperpnea of dry air during training is associated with airway inflammatory changes and remodeling. A response during exercise that is related to pollution or allergen is considered EIB. Ozone and particulate matter are the most widespread pollutants of concern for the exercising population; chronic exposure can lead to new-onset asthma and EIB. Freshly generated emissions particulate matter less than 100 nm is most harmful. Evidence for acute and long-term effects from exercise while inhaling high levels of ozone and/or particulate matter exists. Much evidence supports a relationship between development of airway disorders and exercise in the chlorinated pool. Swimmers typically do not respond in the pool; however, a large percentage responds to a dry air exercise challenge. Studies support oxidative stress mediated pathology for pollutants and a more severe acute response occurs in the asthmatic. Winter sport athletes and swimmers have a higher prevalence of EIB, asthma and airway remodeling than other athletes and the general population. Because of fossil fuel powered ice resurfacers in ice rinks, ice rink athletes have shown high rates of EIB and asthma. For the athlete training in the urban environment, training during low traffic hours and in low traffic areas is suggested.

Health promotion activities of sports clubs and coaches, and health and health behaviours in youth participating in sports clubs: the Health Promoting Sports Club study

Introduction

Sports clubs form a potential setting for health promotion, but the research is limited. The aim of the Health Promoting Sports Club (HPSC) study was to elucidate the current health promotion activities of youth sports clubs and coaches, and to investigate the health behaviours and health status of youth participating in sports clubs compared to non-participants.

Methods and analysis

The study design employs cross-sectional multilevel and multimethod research with aspirations to a prospective cohort study in the next phase. The setting-based variables at sports clubs and coaching levels, and health behaviour variables at the individual level, are investigated using surveys; and total levels of physical activity are assessed using objective accelerometer measurements. Health status variables will be measured by preparticipation screening. The health promotion activity of sports clubs (n=154) is evaluated by club officials (n=313) and coaches (n=281). Coaches and young athletes aged 14–16 (n=759) years evaluate the coaches’ health promotion activity. The survey of the adolescents’ health behaviours consist of two data sets—the first is on their health behaviours and the second is on musculoskeletal complaints and injuries. Data are collected via sports clubs (759 participants) and schools 1650 (665 participants and 983 non-participants). 591 (418 athletes and 173 non-athletes) youth, have already participated in preparticipation screening. Screening consists of detailed personal medical history, electrocardiography, flow-volume spirometry, basic laboratory analyses and health status screening, including posture, muscle balance, and static and dynamic postural control tests, conducted by sports and exercise medicine specialists.

Ethics and dissemination

The HPSC study is carried out conforming with the declaration of Helsinki. Ethical approval was received from the Ethics Committee of Health Care District of Central Finland. The HPSC study is close-to-practice, which generates foundations for development work within youth sports clubs.

Airway dysfunction and inflammation in pool- and non-pool-based elite athletes

PURPOSE

This study sought to determine and compare the levels of airway dysfunction and inflammation in a large cohort of symptomatic international athletes from pool- and non-pool-based sporting backgrounds. In total, 118 athletes were recruited.

METHODS

All subjects had symptoms of exercise asthma and were steroid naïve. They completed baseline spirometry, a symptom score, exhaled nitric oxide, a eucapnic voluntary hyperventilation (EVH) test, and a postchallenge induced sputum and urine test.

RESULTS

Pool-based athletes had better lung function (FEV1 = 110% vs 102% predicted, mean difference = 8.200 ± 2.339, P = 0.0006 and FVC = 5.64 vs 4.75 L, mean difference = 0.8855 ± 0.1951, P < 0.0001) and more marked airways hyper-reactivity (AHR) (percent drop in FEV1 after EVH = 18.14 vs 11.47, mean difference = 6.67, 95% confidence interval = 2.89-10.53, P = 0.0009). More pool-based athletes had a positive EVH test (72% pool vs 39% nonpool), but there was no difference between groups with respect to eosinophilic inflammation (sputum eosinophil percentage: pool = 2.07, nonpool = 2.28, P = 0.77; exhaled nitric oxide: pool = 32.54, nonpool = 35.77, P = 0.60). Athletes with a positive EVH test had less neutrophilic inflammation (P = 0.01) and more epithelial cells (P = 0.03) in their sputum.

CONCLUSIONS

Pool-based endurance athletes have greater evidence of AHR than non-pool-based athletes but no evidence of greater eosinophilic airway inflammation. Athletes who test positive on EVH are more likely to be eosinophilic and have higher levels of epithelial cells in their sputum.

Swimming and Asthma: Differences between Women and Men

Background and Aim. Asthma is common in endurance athletes including swimmers. Our aim was to study gender differences in asthma, allergy, and asthmatic symptoms in swimmers and investigate the effects of varying intensities of physical exercise on competitive swimmers with asthma. Methods. Three hundred highly trained swimmers (156 females and 144 males) were studied by a questionnaire. Their mean (±SD) ages were 17 ± 3 and 19 ± 3 years, and they had training history of 7 ± 2 and 7 ± 3 years in females and males, respectively. Gender differences in asthma, allergy, and respiratory symptoms were examined. Special attention was focused on asthmatic swimmers, their allergies and respiratory symptoms during swimming at different intensities. Results. The prevalence of physician-diagnosed asthma was 19% for females and males. No gender differences in asthma or respiratory symptoms were found. Males reported allergies significantly more often than females (P = 0.007). Gender difference was found in respiratory symptoms among swimmers with physician-diagnosed asthma because females reported symptoms significantly more often (P = 0.017) than males. Asthmatic females also reported symptoms significantly more often at moderate intensity swimming (P = 0.003) than males especially for coughing. Discussion. Gender difference in prevalence of asthma was not found in swimmers. However, allergy was reported significantly more by male swimmers. Male swimmers with asthma reported significantly more cases having family history of asthma, which may be a sign of selection of asthma-friendly sport. Moderate intensity swimming seemed to induce significantly more symptoms especially coughing in asthmatic females.