Fractional Exhaled NO and Serum Pneumoproteins after Swimming in a Chlorinated Pool

Pulmonary function in swimmers exposed to disinfection by-products: a narrative review

Swimming produces many psychophysiological effects, including blood, hormonal, enzymatic, pulmonary, cardiovascular and energetic adaptations. However, asthma and allergies are becoming increasingly prevalent medical issues among elite endurance-trained swimmers, where exercise-induced asthma or bronchospasm is frequently reported. Heavy endurance swimming training, especially under adverse conditions, stresses the airway mucosa, leading to inflammatory changes, as observed in induced sputum in competitive swimmers. In addition, chlorine-based disinfectants (CBDs) are commonly used in indoor pools due to their effectiveness and lower relative cost. Many of these substances have carcinogenic and genotoxic properties, and exposure to DBPs have been linked to adverse respiratory effects. The association between long-term exposure to a chlorinated swimming pool and elevated serum sIgE levels suggests a link between allergens, chlorine exposure and the development of various pulmonary dysfunctions. Thus, the combination of intense and repeated physical endurance training over extended periods, along with suboptimal environmental conditions, may contribute to the development of rhinitis, asthma and bronchial hyperresponsiveness in athletes. While occasional or low-level exposure to chlorine might not be harmful, regular swimmers, especially those at competitive levels, are at a higher risk of developing respiratory disorders. Because these potential risks of exposure to CBDs must be balanced against the benefits of swimming and the risk of microbial infections in pools, we recommend better pool management and regular health checks for swimmers. Fortunately, the reduction of bronchial symptoms in swimmers who reduce training volume and intensity suggests that the negative effects on pulmonary function may be reversible. For these reasons, it is crucial to develop effective respiratory protection strategies, including medical interventions and modifications to the pool environment. Practical steps such as reducing chlorine use, ensuring proper hygiene before swimming and using swim caps can minimise risks. Research should also explore safer alternatives to CBDs, such as ozonation, and improved ventilation to reduce air pollutants.

Exercise-induced bronchoconstriction in elite athletes: a narrative review

Exercise-induced bronchoconstriction (EIB) is the most common chronic disease among elite athletes and when left untreated, can impact both respiratory health and sports performance. In recent years, there has been an increase in the awareness and detection of EIB in elite athletes. This narrative review aims to evaluate the risk, prevention, diagnosis, medication, and anti-doping policies of EIB in elite athletes, and to provide more references for athletes with EIB. The results showed that athletes of endurance, winter, and water sports generally have a higher prevalence of EIB than athletes of other sports. Adaptive warm-up before formal exercise and using heat exchange masks at low temperatures are effective ways for athletes to prevent EIB. For physicians, the exercise challenge test and eucapnic voluntary hyperpnea are the recommended diagnostic methods for EIB in athletes. The treatment of athletes with EIB is medication-based, such as inhaled corticosteroids and beta-2 agonists, but current anti-doping policies should be considered when used.

The acute effects of endurance exercise on epithelial integrity of the airways in athletes and non-athletes: A systematic review and meta-analysis

INTRODUCTION

Acute endurance exercise may induce airway epithelium injury. However, the response of epithelial integrity markers of the airways including club cell secretory protein (CC16) and surfactant protein D (SP-D) to endurance exercise have not been systematically reviewed. Therefore, the aim of this systematic review and meta-analysis was to assess the acute effects of endurance exercise on markers of epithelial integrity of the airways (CC16, SP-D and the CC16/SP-D ratio) in athletes and non-athletes.

METHODS

A systematic search was performed utilizing PubMed/Medline, EMBASE, Web of Science, and hand searching bibliographies of retrieved articles through to September 2022. Based on the inclusion criteria, articles with available data about the acute effects of endurance exercise on serum or plasma concentrations of CC16, SP-D and CC16/SP-D ratio in athletes and non-athletes were included. Quality assessment of studies and statistical analysis were conducted via Review Manager 5.4 software.

RESULTS

The search resulted in 908 publications. Finally, thirteen articles were included in the review. Acute endurance exercise resulted in an increase in CC16 (P = 0.0006, n = 13) and CC16/SP-D ratio (P = 0.005, n = 2) whereas SP-D (P = 0.47, n = 3) did not change significantly. Subgroup analysis revealed that the type (P = 0.003), but not the duration of exercise (P = 0.77) or the environmental temperature (P = 0.06) affected the CC16 response to endurance exercise.

CONCLUSIONS

Acute endurance exercise increases CC16 and the CC16/SP-D ratio, as markers of epithelial integrity, but not SP-D in athletes and non-athletes.

Health effects of exposure to chlorination by-products in swimming pools

Concerns have been raised regarding the potential negative effects on human health of water disinfectants used in swimming pools. Among the disinfection options, the approaches using chlorine-based products have been typically preferred. Chlorine readily reacts with natural organic matter that are introduced in the water mainly through the bathers, leading to the formation of potentially harmful chlorination by-products (CBPs). The formation of CBPs is of particular concern since some have been epidemiologically associated with the development of various clinical manifestations. The higher the concentration of volatile CBPs in the water, the higher their concentration in the air above the pool, and different routes of exposure to chemicals in swimming pools (water ingestion, skin absorption, and inhalation) contribute to the individual exposome. Some CBPs may affect the respiratory and skin health of those who stay indoor for long periods, such as swimming instructors, pool staff, and competitive swimmers. Whether those who use chlorinated pools as customers, particularly children, may also be affected has been a matter of debate. In this article, we discuss the current evidence regarding the health effects of both acute and chronic exposures in different populations (work-related exposures, intensive sports, and recreational attendance) and identify the main recommendations and unmet needs for research in this area.

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.

Gender-dependent association between exhaled nitric oxide and the CC16 38AA genotype in young school children

Background

Studies that investigated the association between the CC16 A38G polymorphism and the risk of asthma yielded conflicting results. The aim of this study among schoolchildren was to assess the relationships of CC16 A38G polymorphism with aeroallergen sensitization and fractional exhaled nitric oxide (FeNO), two outcomes predicting asthma later in life.

Methods

The study included 139 children (72 boys), median age of 7.7. Information on each child's health, lifestyle, and environment was collected through a questionnaire completed by their parents. CC16 genotypes were determined using urinary DNA. We measured FeNO, the CC16 protein in urine and nasal lavage fluid and aeroallergen‐specific immunoglobulin E in nasal mucosa fluid.

Results

Children with the homozygous mutant CC16 38AA genotype had higher odds of increased FeNO (>30 ppb) compared with their peers with the wild‐type genotype 38GG (OR, 9.85; 95% CI, 2.09‐46.4; P = .004). This association was female gender specific (P = .002) not being observed in boys (P = .40). It was also independent of allergic sensitization, which yet emerged as the strongest predictor of FeNO along with the use of bleach for house cleaning. Children with the CC16 38AA genotype had lower covariates‐adjusted urinary CC16 levels than those with 38GG (median, μg/L, 1.17 vs 2.08, P = .02).

Conclusion

Our study suggests that the CC16 38AA allele promotes airway inflammation as measured by FeNO through a gender‐dependent association. Deficient levels of CC16 in the deep lung, measured noninvasively in urine, as a possible proxy for serum CC16, might underlie this promoting effect.

Exercise-induced laryngeal obstruction: Quality initiative to improve assessment and management

INTRODUCTION

Exercise-induced laryngeal obstruction (EILO) affects 2-3% of the general population and 5.1% of elite athletes. Symptoms arise during high-intensity exercise and resolve at rest. EILO is often misdiagnosed as exercise-induced asthma as both conditions can present with dyspnea, chest tightness and cough. The purpose of this quality initiative was to identify patient characteristics that predict a higher likelihood of EILO, streamline referrals for exercise-endoscopy testing and avoid unnecessary medications.

METHODS

A retrospective chart review included patients referred to a pediatric tertiary center between 2013 and 2018 for suspected EILO requesting exercise endoscopy. Data was collected from the patient chart and referral letters included age, sex, physical activity, medications, symptoms, and results of pulmonary and cardiac function tests.

RESULTS

Between 2013 and 2018, 35 patients (9 males and 26 females, aged 5-18 years) were referred. Only 18 patients developed symptoms during an exercise endoscopy test. The majority were female (15/18), older than 10 years (18/18) and were involved in competitive sports (16/18). Stridor was the most common complaint among all patients referred (24/35) and many reported anxiety and high stress (15/35). The majority (63%) were previously treated with asthma medication. Pulmonary and cardiac function testing was not predictive of EILO.

CONCLUSION

EILO is typically present in adolescent females involved in competitive sports. Anxiety and high stress was commonly noted. The majority were treated with asthma medication even though pulmonary function testing was normal. Recognition of this patient profile should improve timely access to appropriate diagnostic assessments, avoid unnecessary medical treatment, and promote a return to optimal athletic performance.

Exposure to disinfection by-products in swimming pools and biomarkers of genotoxicity and respiratory damage - The PISCINA2 Study

BACKGROUND

Swimming in pools is a healthy activity that entails exposure to disinfection by-products (DBPs), some of which are irritant and genotoxic.

OBJECTIVES

We evaluated exposure to DBPs during swimming in a chlorinated pool and the association with short-term changes in genotoxicity and lung epithelium permeability biomarkers.

METHODS

Non-smoker adults (N = 116) swimming 40 min in an indoor pool were included. We measured a range of biomarkers before and at different times after swimming: trihalomethanes (THMs) in exhaled breath (5 min), trichloroacetic acid (TCAA) in urine (30 min), micronuclei in lymphocytes (1 h), serum club cell protein (CC16) (1 h), urine mutagenicity (2 h) and micronuclei in reticulocytes (4 days in a subset, N = 19). Several DBPs in water and trichloramine in air were measured, and physical activity was extensively assessed. We estimated interactions with polymorphisms in genes related to DBP metabolism.

RESULTS

Median level of chloroform, brominated and total THMs in water was 37.3, 9.5 and 48.5, μg/L, respectively, and trichloramine in air was 472.6 μg/m³. Median exhaled chloroform, brominated and total THMs increased after swimming by 10.9, 2.6 and 13.4, μg/m³, respectively. Creatinine-adjusted urinary TCAA increased by 3.1 μmol/mol. Micronuclei in lymphocytes and reticulocytes, urine mutagenicity and serum CC16 levels remained unchanged after swimming. Spearman correlation coefficients showed no association between DBP exposure and micronuclei in lymphocytes, urine mutagenicity and CC16. Moderate associations were observed for micronuclei in reticulocytes and DBP exposure.

CONCLUSIONS

The unchanged levels of the short-term effect biomarkers after swimming and null associations with personal estimates of exposure to DBPs suggest no measurable effect on genotoxicity in lymphocytes, urine mutagenicity and lung epithelium permeability at the observed exposure levels. The moderate associations with micronuclei in reticulocytes require cautious interpretation given the reduced sample size.

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.

Impairment on Cardiopulmonary Function after Marathon: Role of Exhaled Nitric Oxide

BACKGROUND

The endurance exercise is capable of inducing skeletal muscle, heart, and respiratory fatigue, evidenced by morphofunctional cardiac changes, release of myocardial injury biomarkers, and reduction of maximal voluntary ventilation and oxygen consumption (VO2) at peak exercise.

PURPOSE

The aim of this study was to investigate whether marathoners present cardiac fatigue after marathon and whether it correlates with pulmonary levels of exhaled nitric oxide (eNO) and pulmonary inflammation.

METHODS

31 male marathoners, age 39 ± 9 years, were evaluated by cardiopulmonary exercise test three weeks before and between three and 15 days after a marathon; eNO analysis and spirometry were evaluated before, immediately after, and 24 and 72 hours after the marathon, and sputum cellularity and cytokine level were assessed before and after the marathon.

RESULTS

Marathon induced an increase in the percentage of macrophages, neutrophils (from 0.65% to 4.28% and 6.79% to 14.11%, respectively), and epithelial cells and a decrease in cytokines in induced sputum, followed by an increase in eNO concentration (20 ± 11 to 35 ± 19 ppb), which presented a significant reduction 24 and 72 hours after marathon (9 ± 12 e 12 ± 9 ppb, p < 0.05). We observed a decrease in the spirometry parameters in all time points assessed after the marathon (p < 0.05) as well as in cardiopulmonary capacity, evidenced by a reduction in VO2 and ventilation peaks (57 ± 6 to 55 ± 6 mL·min-1·Kg-1 and 134 ± 19 to 132 ± 18 Lpm, respectively, p < 0.05). Finally, we observed a negative correlation between the decrease in forced expiratory volume and decrease in eNO 24 and 72 hours after marathon (r = -0.4, p = 0.05).

CONCLUSION

Reduction in eNO bioavailability after marathon prevents the reduction in cardiopulmonary capacity induced by acute inflammatory pattern after marathon.

Swimming versus running: effects on exhaled breath condensate pro-oxidants and pH

PURPOSE

The respiratory redox-state of swimmers can be affected by chronic exposures to chlorinated pools, and the effects of different exercises on it are unknown. Our aim was to compare two exercises performed at high-intensity and under habitual environmental conditions (swimming indoor vs. running outdoor) on the production of pro-oxidants (hydrogen peroxide and nitrite) and pH in exhaled breath condensate (EBC) and spirometry parameters in competitive swimmers chronically exposed to chlorinated pools.

METHODS

Seventeen men and women (mean age ± SD = 21 ± 2 years) swam 3.5 km in an indoor pool treated with Cl_2, and after 2-weeks, they ran 10 km outdoors. The pH_EBC, [H₂O₂]_EBC, [NO₂^-]_EBC, [NO₂^-]_EBC/[NO₂^-]_Plasma and spirometry parameters were analyzed pre-exercise and 20 min and 24 h after exercise ended.

RESULTS

Two mixed models were applied to compare EBC parameters between swimming and running. Lower levels of [H₂O₂]_EBC and [NO₂^-]_EBC (p = 0.008 and p = 0.018, respectively) were found 24-h post-swimming, and the same trend was observed for [NO₂^-]_EBC/[NO₂^-]_Plasma (p = 0.062). Correlations were found in both exercises between pre-exercise levels of pH_EBC, [H₂O₂]_EBC, [NO₂^-]_EBC, and [NO₂^-]_EBC/[NO₂^-]_Plasma and their changes (Δ) after 24-h as well as between [H₂O₂]_EBC and [NO₂^-]_EBC for basal levels and for changes after 24 h. A relationship was also found for running exercise between pulmonary ventilation and changes after 24 h in [H₂O₂]_EBC. Spirometry data were unaffected in both types of exercise.

CONCLUSION

In competitive swimmers, at 24-h acute post-exercise follow-up, swimming decreased and running increased pro-oxidant biomarkers of pulmonary origin, without changes in lung function.

Respiratory, ocular and skin health in recreational and competitive swimmers: Beneficial effect of a new method to reduce chlorine oxidant derivatives

BACKGROUND

Chlorine by-products may irritate the eyes, nose, skin and airways of swimmers and may cause chronic airway inflammation.

OBJECTIVE

To assess the salutary effects on swimmers health of a new method of water disinfection.

METHODS

Recreational (n=320) and competitive swimmers (n=53) participated in the study. The first part of the study (Phase A) was carried out while using the current standard method. The second part (Phase B) began 8 weeks after the new method had been introduced. Total oxidants in air and chlorine species in water were assessed by standard methods. All swimmers completed a questionnaire on health complaints. Exhaled breath condensate (EBC) was used to monitor the levels of leukotriene B4 (LTB₄) and cysteinyl leukotrienes (CysLTs) in airway from competitive swimmers.

RESULTS

The new system resulted in a 75% and 39% reduction in the concentration of total oxidants and of nitrogen trichloride respectively in the air of the swimming pool. With the new system recreational swimmers experienced fewer symptoms of cough and irritation of the eyes, nose and skin. A decrease in eye irritation symptoms was also noted by competitive swimmers. The baseline concentration of CysLTs in EBC decreased significantly in Phase B with respect to Phase A.

CONCLUSIONS

The new method markedly reduced the levels of irritant oxidant substances in the pool atmosphere that resulted in a reduction of eye, nose, skin and cough complaints in recreational swimmers, and eye irritation in competitive swimmers. It was also associated with reduced CysLT levels in the airways of competitive swimmers.

Dynamic real-time monitoring of chloroform in an indoor swimming pool air using open-path Fourier transform infrared spectroscopy

This study used open-path Fourier transform infrared (OP-FTIR) spectroscopy to continuously assess the variation in chloroform concentrations in the air of an indoor swimming pool. Variables affecting the concentrations of chloroform in air were also monitored. The results showed that chloroform concentrations in air varied significantly during the time of operation of the swimming pool and that there were two peaks in chloroform concentration during the time of operation of the pool. The highest concentration was at 17:30, which is coincident with the time with the highest number of swimmers in the pool in a day. The swimmer load was one of the most important factors influencing the chloroform concentration in the air. When the number of swimmers surpassed 40, the concentrations of chloroform were on average 4.4 times higher than the concentration measured without swimmers in the pool. According to the results of this study, we suggest that those who swim regularly should avoid times with highest number of swimmers, in order to decrease the risk of exposure to high concentrations of chloroform. It is also recommended that an automatic mechanical ventilation system is installed to increase the ventilation rate during times of high swimmer load.

Airway dysfunction in elite swimmers: prevalence, impact, and challenges

The prevalence of airway dysfunction in elite swimmers is among the highest in elite athletes. The traditional view that swimmers naturally gravitate toward swimming because of preexisting respiratory disorders has been challenged. There is now sufficient evidence that the higher prevalence of bronchial tone disorders in elite swimmers is not the result of a natural selection bias. Rather, the combined effects of repeated chlorine by-product exposure and chronic endurance training can lead to airway dysfunction and atopy. This review will detail the underpinning causes of airway dysfunction observed in elite swimmers. It will also show that airway dysfunction does not prevent success in elite level swimming. Neither does it inhibit lung growth and might be partially reversible when elite swimmers retire from competition.

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.

Update on the Mechanisms of Pulmonary Inflammation and Oxidative Imbalance Induced by Exercise

The mechanisms involved in the generation of oxidative damage and lung inflammation induced by physical exercise are described. Changes in lung function induced by exercise involve cooling of the airways, fluid evaporation of the epithelial surface, increased contact with polluting substances, and activation of the local and systemic inflammatory response. The present work includes evidence obtained from the different types of exercise in terms of duration and intensity, the effect of both acute performance and chronic performance, and the influence of special conditions such as cold weather, high altitude, and polluted environments. Levels of prooxidants, antioxidants, oxidative damage to biomolecules, and cellularity, as well as levels of soluble mediators of the inflammatory response and its effects on tissues, are described in samples of lung origin. These samples include tissue homogenates, induced sputum, bronchoalveolar lavage fluid, biopsies, and exhaled breath condensate obtained in experimental protocols conducted on animal and human models. Finally, the need to simultaneously explore the oxidative/inflammatory parameters to establish the interrelation between them is highlighted.

Association of serum Clara cell protein CC16 with respiratory infections and immune response to respiratory pathogens in elite athletes

BACKGROUND

Respiratory epithelium integrity impairment caused by intensive exercise may lead to exercise-induced bronchoconstriction. Clara cell protein (CC16) has anti-inflammatory properties and its serum level reflects changes in epithelium integrity and airway inflammation. This study aimed to investigate serum CC16 in elite athletes and to seek associations of CC16 with asthma or allergy, respiratory tract infections (RTIs) and immune response to respiratory pathogens.

METHODS

The study was performed in 203 Olympic athletes. Control groups comprised 53 healthy subjects and 49 mild allergic asthmatics. Serum levels of CC16 and IgG against respiratory viruses and Mycoplasma pneumoniae were assessed. Allergy questionnaire for athletes was used to determine symptoms and exercise pattern. Current versions of ARIA and GINA guidelines were used when diagnosing allergic rhinitis and asthma, respectively.

RESULTS

Asthma was diagnosed in 13.3% athletes, of whom 55.6% had concomitant allergic rhinitis. Allergic rhinitis without asthma was diagnosed in 14.8% of athletes. Mean CC16 concentration was significantly lower in athletes versus healthy controls and mild asthmatics. Athletes reporting frequent RTIs had significantly lower serum CC16 and the risk of frequent RTIs was more than 2-fold higher in athletes with low serum CC16 (defined as equal to or less than 4.99 ng/ml). Athletes had significantly higher anti-adenovirus IgG than healthy controls while only non-atopic athletes had anti-parainfluenza virus IgG significantly lower than controls. In all athletes weak correlation of serum CC16 and anti-parainfluenza virus IgG was present (R = 0.20, p < 0.01). In atopic athletes a weak positive correlations of CC16 with IgG specific for respiratory syncytial virus (R = 0.29, p = 0.009), parainfluenza virus (R = 0.31, p = 0.01) and adenovirus (R = 0.27, p = 0.02) were seen as well.

CONCLUSIONS

Regular high-load exercise is associated with decrease in serum CC16 levels. Athletes with decreased CC16 are more susceptible to respiratory infections. Atopy may be an additional factor modifying susceptibility to infections in subjects performing regular high-load exercise.

Respiratory disorders in endurance athletes - how much do they really have to endure?

Respiratory disorders are often a cause of morbidity in top level endurance athletes, more often compromising their performance and rarely being a cause of death. Pathophysiological events occurring during exercise, such as bronchospasm, are sometimes followed by clear pathological symptoms represented by asthma related to physical exertion or rarely by pulmonary edema induced by a strenuous effort. Both bronchospasm and the onset of interstitial edema induced by exercise cannot be considered pathological per se, but are more likely findings that occur in several healthy subjects once physical exhaustion during exertion has been reached. Consequently, we get a vision of the respiratory system perfectly tailored to meet the body's metabolic demands under normal conditions but which is limited when challenged by strenuous exercise, in particular when it happens in an unfavorable environment. As extreme physical effort may elicit a pathological response in healthy subjects, due to the exceeding demand in a perfectly functional system, an overview of the main tools both enabling the diagnosis of respiratory impairment in endurance athletes in a clinical and preclinical phase has also been described.

Airway dysfunction in elite athletes--an occupational lung disease?

Airway dysfunction is prevalent in elite endurance athletes and when left untreated may impact upon both health and performance. There is now concern that the intensity of hyperpnoea necessitated by exercise at an elite level may be detrimental for an athlete's respiratory health. This article addresses the evidence of causality in this context with the aim of specifically addressing whether airway dysfunction in elite athletes should be classified as an occupational lung disease. The approach used highlights a number of concerns and facilitates recommendations to ensure airway health is maintained and optimized in this population. We conclude that elite athletes should receive the same considerations for their airway health as others with potential and relevant occupational exposures.

Respiratory function and changes in lung epithelium biomarkers after a short-training intervention in chlorinated vs. ozone indoor pools

Background

Swimming in indoor pools treated with combined chemical treatments (e.g. ozone) may reduce direct exposure to disinfection byproducts and thus have less negative effects on respiratory function compared to chlorinated pools. The aim of this study is to analyze the effects of a short-term training intervention on respiratory function and lung epithelial damage in adults exercising in indoor swimming pool waters treated with different disinfection methods (chlorine vs. ozone with bromine).

Methods

Lung permeability biomakers [surfactant protein D (SP-D) and Clara cell secretory protein (CC16) in plasma] and forced expiratory volumes and flow (FEV1, FVC and FEF_25–75) were measured in 39 healthy adults. Thirteen participants swam during 20 sessions in a chlorinated pool (CP), 13 performed and equivolumic intervention in an ozone pool (OP) and 13 were included in a control group (CG) without exposition.

Results

Median plasma CC16 levels increased in CP swimmers (4.27±3.29 and 6.62±5.51 µg/L, p = 0.01, pre and post intervention respectively) while no significant changes in OP and CG participants were found. No significant changes in median plasma SP-D levels were found in any of the groups after the training period. FVC increased in OP (4.26±0.86 and 4.43±0.92 L, p<0.01) and CP swimmers (4.25±0.86 and 4.35±0.85 L, p<0.01). FEV1 only increased in OP swimmers (3.50±0.65 and 3.59±0.67, p = 0.02) and FEF_25–75 decreased in CP swimmers (3.70±0.87 and 3.37±0.67, p = 0.02).

Conclusion

Despite lung function being similar in both groups, a higher lung permeability in CP compared to OP swimmers was found after a short-term swimming program. Combined chemical treatments for swimming pools such as ozone seem to have less impact on lung epithelial of swimmers compared to chlorinated treated pools.

Risks of new-onset allergic sensitization and airway inflammation after early age swimming in chlorinated pools

RATIONALE

Irritant chlorination products in swimming pools can cause respiratory problems in swimmers but their possible implication in allergies development is still unclear.

OBJECTIVES

To assess prospectively whether early-life attendance at chlorinated pools increases the risks of IgE sensitization and of airways inflammation later during childhood.

METHODS

We conducted a two-year prospective study among 196 kindergarten children (mean age of 5.7 years, 54% of boys). We measured exhaled nitric oxide (eNO) and aeroallergen-specific IgE in nasal mucosa. Parents completed a questionnaire about the child's health, chlorinated pool attendance and potential confounders.

MAIN RESULTS

Ever swimming at indoor or outdoor chlorinated pools before the age of three years was associated with higher odds for new-onset IgE sensitization to house dust mite (adjusted odds ratio [aOR] 2.93, 95% confidence interval [CI] 1.14-7.55) and for new-onset increased eNO (>15 ppb; aOR, 4.54, 95% CI 1.48-13.9). For both outcomes, aORs increased dose-dependently with time spent in chlorinated pools with values reaching, respectively, 3.60 (95% CI 1.21-10.7) and 5.92 (95% CI 1.72-20.5) when the cumulative pool attendance exceeded 60 h These risks appeared independently of each other, of parental history of allergies and of pre-existing diseases, including eczema, which at baseline was more prevalent in early swimmers (aOR, 2.91; 95% CI 1.23-6.89). Such associations were not seen with IgE sensitization to pollen or cat allergens.

CONCLUSION

Attendance at chlorinated swimming pools in early life is associated with higher risks of new-onset airways inflammation and IgE sensitization to house dust mite, independently of other risk factors.

Respiratory health of elite athletes - preventing airway injury: a critical review

Elite athletes, particularly those engaged in endurance sports and those exposed chronically to airborne pollutants/irritants or allergens, are at increased risk for upper and lower airway dysfunction. Airway epithelial injury may be caused by dehydration and physical stress applied to the airways during severe exercise hyperpnoea and/or by inhalation of noxious agents. This is thought to initiate an inflammatory cascade/repair process that, ultimately, could lead to airway hyperresponsiveness (AHR) and asthma in susceptible athletes. The authors review the evidence relating to prevention or reduction of the risk of AHR/asthma development. Appropriate measures should be implemented when athletes exercise strenuously in an attempt to attenuate the dehydration stress and reduce the exposure to noxious airborne agents. Environmental interventions are the most important. Non-pharmacological strategies can assist, but currently, pharmacological measures have not been demonstrated to be effective. Whether early prevention of airway injury in elite athletes can prevent or reduce progression to AHR/asthma remains to be established.

Lung function in volunteers before and after exposure to trichloramine in indoor pool environments and asthma in a cohort of pool workers

OBJECTIVES

Exposure to trichloramine (NCl(3)) in indoor swimming-pool environments is known to cause mucous membrane irritation, but if it gives rise to changes in lung function or asthma in adults is not known. (1) We determined lung function in volunteers before and after exposure to indoor pool environments. (2) We studied the occurrence of respiratory symptoms and asthma in a cohort of pool workers. DESIGN/METHODS/PARTICIPANTS: (1) We studied two groups of volunteers, 37 previously non-exposed healthy persons and 14 pool workers, who performed exercise for 2 h in an indoor pool environment. NCl(3) in air was measured during pool exposures and in 10 other pool environments. Filtered air exposures were used as controls. Lung function and biomarkers of pulmonary epithelial integrity were measured before and after exposure. (2) We mailed a questionnaire to 1741 persons who indicated in the Swedish census 1990 that they worked at indoor swimming-pools.

RESULTS

(1) In previously non-exposed volunteers, statistically significant decreases in FEV(1) (forced expiratory volume) and FEV(%) (p=0.01 and 0.05, respectively) were found after exposure to pool air (0.23 mg/m(3) of NCl(3)). In pool workers, a statistically significant decrease in FEV(%) (p=0.003) was seen (but no significant change of FEV(1))(.) In the 10 other pool environments the median NCl(3) concentration was 0.18 mg/m(3). (2) Our nested case/control study in pool workers found an OR for asthma of 2.31 (95% CI 0.79 to 6.74) among those with the highest exposure. Exposure-related acute mucous membrane and respiratory symptoms were also found.

CONCLUSIONS

This is the first study in adults showing statistically significant decreases in lung function after exposure to NCl(3). An increased OR for asthma among highly exposed pool workers did not reach statistical significance, but the combined evidence supports the notion that current workroom exposures may contribute to asthma development. Further research on sensitive groups is warranted.

Health effects of disinfection by-products in chlorinated swimming pools

Increased attendance at swimming pools is correlated with higher input of organic and minerals pollutants introduced by swimmers in the swimming pool water. In most swimming pools, microbiological control is performed by disinfection with the addition of chlorine. Chlorine is now well-known to lead to the formation of many disinfection by-products (DBPs) including trihalomethanes and chloramines. The hypothesis of a link between the presence of eye and skin irritation syndromes in swimmers and contact with swimming pool water treated with chlorine was initially proposed by Mood (1953). During recent decades many epidemiological studies have described the importance of DBPs generated with natural or imported organic matter present in water. Many of these DBPs are suspected to be toxic or even carcinogenic. Trihalomethanes and haloacetic acid families are the most studied but others DBPs, like chloral hydrate, haloacetonitriles, N-nitrosodimethylamine and the bromate ion, are emerging compounds of interest. Epidemiological data about the risk of cancer are still controversial. However, numerous publications highlight a toxic risk especially the risk of allergy and respiratory symptoms for babies and elite swimmers. The few publications dedicated to risk assessment do not suggest increased risk, other than for elite swimmers. These publications are likely to underestimate the risk associated with DBPs because of the lack of data in the literature precludes the calculation of risk associated with certain compounds or certain pathways. Thus for regulations, the need to take into account the risks associated with disinfection by-products is now important without forgetting the need of the control of microbiological hazards in swimming pools.

Short-term changes in respiratory biomarkers after swimming in a chlorinated pool

BACKGROUND

Swimming in chlorinated pools involves exposure to disinfection by-products (DBPs) and has been associated with impaired respiratory health.

OBJECTIVES

We evaluated short-term changes in several respiratory biomarkers to explore mechanisms of potential lung damage related to swimming pool exposure.

METHODS

We measured lung function and biomarkers of airway inflammation [fractional exhaled nitric oxide (FeNO), eight cytokines, and vascular endothelial growth factor (VEGF) in exhaled breath condensate], oxidative stress (8-isoprostane in exhaled breath condensate), and lung permeability [surfactant protein D (SP-D) and the Clara cell secretory protein (CC16) in serum] in 48 healthy nonsmoking adults before and after they swam for 40 min in a chlorinated indoor swimming pool. We measured trihalomethanes in exhaled breath as a marker of individual exposure to DBPs. Energy expenditure during swimming, atopy, and CC16 genotype (rs3741240) were also determined.

RESULTS

Median serum CC16 levels increased from 6.01 to 6.21 microg/L (average increase, 3.3%; paired Wilcoxon test p = 0.03), regardless of atopic status and CC16 genotype. This increase was explained both by energy expenditure and different markers of DBP exposure in multivariate models. FeNO was unchanged overall but tended to decrease among atopics. We found no significant changes in lung function, SP-D, 8-isoprostane, eight cytokines, or VEGF.

CONCLUSIONS

We detected a slight increase in serum CC16, a marker of lung epithelium permeability, in healthy adults after they swam in an indoor chlorinated pool. Exercise and DBP exposure explained this association, without involving inflammatory mechanisms. Further research is needed to confirm the results, establish the clinical relevance of short-term serum CC16 changes, and evaluate the long-term health impacts.

Childhood asthma and environmental exposures at swimming pools: state of the science and research recommendations

OBJECTIVES

Recent studies have explored the potential for swimming pool disinfection by-products (DBPs), which are respiratory irritants, to cause asthma in young children. Here we describe the state of the science on methods for understanding children's exposure to DBPs and biologics at swimming pools and associations with new-onset childhood asthma and recommend a research agenda to improve our understanding of this issue.

DATA SOURCES

A workshop was held in Leuven, Belgium, 21-23 August 2007, to evaluate the literature and to develop a research agenda to better understand children's exposures in the swimming pool environment and their potential associations with new-onset asthma. Participants, including clinicians, epidemiologists, exposure scientists, pool operations experts, and chemists, reviewed the literature, prepared background summaries, and held extensive discussions on the relevant published studies, knowledge of asthma characterization and exposures at swimming pools, and epidemiologic study designs.

SYNTHESIS

Childhood swimming and new-onset childhood asthma have clear implications for public health. If attendance at indoor pools increases risk of childhood asthma, then concerns are warranted and action is necessary. If there is no such relationship, these concerns could unnecessarily deter children from indoor swimming and/or compromise water disinfection.

CONCLUSIONS

Current evidence of an association between childhood swimming and new-onset asthma is suggestive but not conclusive. Important data gaps need to be filled, particularly in exposure assessment and characterization of asthma in the very young. Participants recommended that additional evaluations using a multidisciplinary approach are needed to determine whether a clear association exists.