Environmental challenges facing athletes, stakeholders and spectators at Paris 2024 Olympic and Paralympic Games: an evidence-based review of mitigation strategies and recommendations.

The upcoming Paris 2024 Olympic and Paralympic Games could face environmental challenges related to heat, air quality and water quality. These challenges will pose potential threats to athletes and impact thousands of stakeholders and millions of spectators. Recognising the multifaceted nature of these challenges, a range of strategies will be essential for mitigating adverse effects on participants, stakeholders and spectators alike. From personalised interventions for athletes and attendees to comprehensive measures implemented by organisers, a holistic approach is crucial to address these challenges and the possible interplay of heat, air and water quality factors during the event. This evidence-based review highlights various environmental challenges anticipated at Paris 2024, offering strategies applicable to athletes, stakeholders and spectators. Additionally, it provides recommendations for Local Organising Committees and the International Olympic Committee that may be applicable to future Games. In summary, the review offers solutions for consideration by the stakeholders responsible for and affected by the anticipated environmental challenges at Paris 2024.

Ozone exposure limits cardiorespiratory function during maximal cycling exercise in endurance athletes.

Ground-level ozone (O3) is a potent air pollutant well recognized to acutely induce adverse respiratory symptoms and impairments in pulmonary function. However, it is unclear how the hyperpnea of exercise may modulate these effects, and the subsequent consequences on exercise performance. We tested the hypothesis that pulmonary function and exercise capability would be diminished, and symptom development would be increased during peak real-world levels of O3 exposure compared with room air. Twenty aerobically trained participants [13 M, 7 F; maximal O2 uptake (V̇o2max), 64.1 ± 7.0 mL·kg-1·min-1] completed a three-visit double-blinded, randomized crossover trial. Following a screening visit, participants were exposed to 170 ppb O3 or room air (<10 ppb O3) on separate visits during exercise trials, consisting of a 25-min moderate-intensity warmup, 30-min heavy-intensity bout, and a subsequent time-to-exhaustion (TTE) performance test. No differences in O2 uptake or ventilation were observed during submaximal exercise between conditions. During the TTE test, we observed significantly lower end-exercise O2 uptake (-3.2 ± 4.3%, P = 0.004), minute ventilation (-3.2 ± 6.5%, P = 0.043), tidal volume (-3.6 ± 5.1%, P = 0.008), and a trend toward lower exercise duration in O3 compared with room air (-10.8 ± 26.5%, P = 0.092). As decreases in O2 uptake and alterations in respiratory pattern were also present at matched time segments between conditions, a limitation of oxygen transport seems likely during maximal exercise. A more comprehensive understanding of the direct mechanisms that limit oxygen transport during exercise in high-pollutant concentrations is key for mitigating performance changes.NEW & NOTEWORTHY We demonstrate that in highly trained endurance athletes, exposure to peak real-world levels of O3 air pollution (170 ppb) significantly diminishes O2 uptake along with corresponding changes in ventilation during maximal exercise. As no differences were observed during extended submaximal exercise, a combined effect of effective dose of pollution and exercise intensity on severity of responses seems likely.

Physical activity and combined hormonal contraception: association with female students' perception of menstrual symptoms.

Aim: The aim of this study was to examine the association between physical activity (PA) and combined hormonal contraceptive (CHC) on female students' self perceptio of their menstrual cycle symptoms. Methods: Healthy French female students (n = 834) completed an online questionnaire to assess their PA level (Group 1: non-active; Group 2: moderate physical activity; Group 3: high physical activity; Group 4: very high physical activity), menstrual status or contraception use, self-reported diet and medication, impact on engagement in some social activities, and self-assessment of perceived mental and physical symptoms during the week prior to menses (PM) for students with a normal menstrual cycle (NMC), and the week of menses (ME) for normal menstrual cycle students and those using combined hormonal contraception. Results: Whatever the conditions (PM and ME, NMC and CHC), fewer self-perceived symptoms and self-reported alteration in fat intake were reported by the students in Group 4, and more analgesic and anti-inflammatory medication use was reported by Group 1. Fewer self-perceived symptoms were also found in CHC vs NMC female students for all physical activity levels, but in a more marked way when associated with very high physical activity. In addition, less university and sports practice absenteeism was observed with high and very high physical activity. Conclusion: In conclusion, the perception of menstrual cycle symptoms was lower with very high physical activity, as with combined hormonal contraception. Moreover, female students training more than 5 h/week also reported less university absenteeism and impairment in physical activities. Further studies are necessary to establish the causal link of physical activity and combined hormonal contraception on menstrual symptoms.

Personal strategies to mitigate the effects of air pollution exposure during sport and exercise: a narrative review and position statement by the Canadian Academy of Sport and Exercise Medicine and the Canadian Society for Exercise Physiology.

Air pollution is among the leading environmental threats to health around the world today, particularly in the context of sports and exercise. With the effects of air pollution, pollution episodes (eg, wildfire conflagrations) and climate change becoming increasingly apparent to the general population, so have their impacts on sport and exercise. As such, there has been growing interest in the sporting community (ie, athletes, coaches, and sports science and medicine team members) in practical personal-level actions to reduce the exposure to and risk of air pollution. Limited evidence suggests the following strategies may be employed: minimising all exposures by time and distance, monitoring air pollution conditions for locations of interest, limiting outdoor exercise, using acclimation protocols, wearing N95 face masks and using antioxidant supplementation. The overarching purpose of this position statement by the Canadian Academy of Sport and Exercise Medicine and the Canadian Society for Exercise Physiology is to detail the current state of evidence and provide recommendations on implementing these personal strategies in preventing and mitigating the adverse health and performance effects of air pollution exposure during exercise while recognising the limited evidence base.

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

OBJECTIVES: To compare the performance of various diagnostic bronchoprovocation tests (BPT) in the assessment of lower airway dysfunction (LAD) in athletes and inform best clinical practice. DESIGN: Systematic review with sensitivity and specificity meta-analyses. DATA SOURCES: PubMed, EBSCOhost and Web of Science (1 January 1990-31 December 2021). ELIGIBILITY CRITERIA: Original full-text studies, including athletes/physically active individuals (15-65 years) who underwent assessment for LAD by symptom-based questionnaires/history and/or direct and/or indirect BPTs. RESULTS: In 26 studies containing data for quantitative meta-analyses on BPT diagnostic performance (n=2624 participants; 33% female); 22% had physician diagnosed asthma and 51% reported LAD symptoms. In athletes with symptoms of LAD, eucapnic voluntary hyperpnoea (EVH) and exercise challenge tests (ECTs) confirmed the diagnosis with a 46% sensitivity and 74% specificity, and 51% sensitivity and 84% specificity, respectively, while methacholine BPTs were 55% sensitive and 56% specific. If EVH was the reference standard, the presence of LAD symptoms was 78% sensitive and 45% specific for a positive EVH, while ECTs were 42% sensitive and 82% specific. If ECTs were the reference standard, the presence of LAD symptoms was 80% sensitive and 56% specific for a positive ECT, while EVH demonstrated 65% sensitivity and 65% specificity for a positive ECT. CONCLUSION: In the assessment of LAD in athletes, EVH and field-based ECTs offer similar and moderate diagnostic test performance. In contrast, methacholine BPTs have lower overall test performance. PROSPERO REGISTRATION NUMBER: CRD42020170915.

Diagnosis and management of allergy and respiratory disorders in sport: An EAACI task force position paper.

Allergy and respiratory disorders are common in young athletic individuals. In the context of elite sport, it is essential to secure an accurate diagnosis in order to optimize health and performance. It is also important, however, to consider the potential impact or consequences of these disorders, in recreationally active individuals engaging in structured exercise and/or physical activity to maintain health and well-being across the lifespan. This EAACI Task Force was therefore established, to develop an up-to-date, research-informed position paper, detailing the optimal approach to the diagnosis and management of common exercise-related allergic and respiratory conditions. The recommendations are informed by a multidisciplinary panel of experts including allergists, pulmonologists, physiologists and sports physicians. The report is structured as a concise, practically focussed document, incorporating diagnostic and treatment algorithms, to provide a source of reference to aid clinical decision-making. Throughout, we signpost relevant learning resources to consolidate knowledge and understanding and conclude by highlighting future research priorities and unmet needs.

International Olympic Committee (IOC) consensus statement on acute respiratory illness in athletes part 1: acute respiratory infections.

Acute illnesses affecting the respiratory tract are common and form a significant component of the work of Sport and Exercise Medicine (SEM) clinicians. Acute respiratory illness (ARill) can broadly be classified as non-infective ARill and acute respiratory infections (ARinf). The aim of this consensus is to provide the SEM clinician with an overview and practical clinical approach to ARinf in athletes. The International Olympic Committee (IOC) Medical and Scientific Commission appointed an international consensus group to review ARill (non-infective ARill and ARinf) in athletes. Six subgroups of the IOC Consensus group were initially established to review the following key areas of ARill in athletes: (1) epidemiology/risk factors for ARill, (2) ARinf, (3) non-infective ARill including ARill due to environmental exposure, (4) acute asthma and related conditions, (5) effects of ARill on exercise/sports performance, medical complications/return-to-sport and (6) acute nasal/vocal cord dysfunction presenting as ARill. Several systematic and narrative reviews were conducted by IOC consensus subgroups, and these then formed the basis of sections in the consensus documents. Drafting and internal review of sections were allocated to 'core' members of the consensus group, and an advanced draft of the consensus document was discussed during a meeting of the main consensus core group in Lausanne, Switzerland on 11 to 12 October 2021. Final edits were completed after the meeting. This consensus document (part 1) focusses on ARinf, which accounts for the majority of ARill in athletes. The first section of this consensus proposes a set of definitions and classifications of ARinf in athletes to standardise future data collection and reporting. The remainder of the consensus paper examines a wide range of clinical considerations related to ARinf in athletes: epidemiology, risk factors, pathology/pathophysiology, clinical presentation and diagnosis, management, prevention, medical considerations, risks of infection during exercise, effects of infection on exercise/sports performance and return-to-sport guidelines.

International Olympic Committee (IOC) consensus statement on acute respiratory illness in athletes part 2: non-infective acute respiratory illness.

Acute respiratory illness (ARill) is common and threatens the health of athletes. ARill in athletes forms a significant component of the work of Sport and Exercise Medicine (SEM) clinicians. The aim of this consensus is to provide the SEM clinician with an overview and practical clinical approach to non-infective ARill in athletes. The International Olympic Committee (IOC) Medical and Scientific Committee appointed an international consensus group to review ARill in athletes. Key areas of ARill in athletes were originally identified and six subgroups of the IOC Consensus group established to review the following aspects: (1) epidemiology/risk factors for ARill, (2) infective ARill, (3) non-infective ARill, (4) acute asthma/exercise-induced bronchoconstriction and related conditions, (5) effects of ARill on exercise/sports performance, medical complications/return-to-sport (RTS) and (6) acute nasal/laryngeal obstruction presenting as ARill. Following several reviews conducted by subgroups, the sections of the consensus documents were allocated to 'core' members for drafting and internal review. An advanced draft of the consensus document was discussed during a meeting of the main consensus core group, and final edits were completed prior to submission of the manuscript. This document (part 2) of this consensus focuses on respiratory conditions causing non-infective ARill in athletes. These include non-inflammatory obstructive nasal, laryngeal, tracheal or bronchial conditions or non-infective inflammatory conditions of the respiratory epithelium that affect the upper and/or lower airways, frequently as a continuum. The following aspects of more common as well as lesser-known non-infective ARill in athletes are reviewed: epidemiology, risk factors, pathology/pathophysiology, clinical presentation and diagnosis, management, prevention, medical considerations and risks of illness during exercise, effects of illness on exercise/sports performance and RTS guidelines.

Environmental factors associated with non-infective acute respiratory illness in athletes: A systematic review by a subgroup of the IOC consensus group on "acute respiratory illness in the athlete".

OBJECTIVES: The aim of this study is to review the evidence available suggesting that environmental conditions represent a risk factor associated with non-infective acute respiratory illness in athletes. DESIGN: Systematic review. METHODS: PubMed, EBSCOhost and Web of Science (1st January 1990-31 July 2020) were searched systematically using keywords related to male and female athletes (i.e. from physically active individuals to elite athletes), aged 15-65 years and a combination of the terms (non-infective acute respiratory illness AND [pollution OR allergies OR climate] AND athletes AND prevalence/incidence/risk factors). RESULTS: A total of seven papers (n = 1567 athletes) addressed our question. Among these, one focused on indoor air pollution, four on chlorinated swimming pool exposure and two on cold air conditions. None was selected for allergies, outdoor air pollution or other climatic conditions. Except rhinitis induced by swimming in chlorinated pools (n = 1), no respiratory disease due to the environment was identified specifically in athletes. The levels of chloramines in swimming pools (n = 2) and air pollutant in arenas (n = 1) were identified as risk factors for rhinitis and respiratory symptoms when exercising. DISCUSSIONS: There is a paucity of data on the prevalence, incidence and risk factors of being acutely exposed to chlorine by-products, air pollution, cold air or altitude on the development of respiratory disease specifically in athletes. Noting the lack of a clear definition of environmentally induced lung disease in athletes, distinct from that of the general population, we addressed the few published management plans to protect athletes' airways for each specific environment.

Is airway damage during physical exercise related to airway dehydration? Inputs from a computational model.

In healthy subjects, at low minute ventilation (V̇e) during physical exercise, the water content and temperature of the airways are well regulated. However, with the increase in V̇e, the bronchial mucosa becomes dehydrated and epithelial damage occurs. Our goal was to demonstrate the correspondence between the ventilatory threshold inducing epithelial damage, measured experimentally, and the dehydration threshold, estimated numerically. In 16 healthy adults, we assessed epithelial damage before and following a 30-min continuous cycling exercise at 70% of maximal work rate, by measuring the variation pre- to postexercise of serum club cell protein (cc16/cr). Blood samples were collected at rest, just at the end of the standardized 10-min warm-up, and immediately, 30 min and 60 min postexercise. Mean V̇e during exercise was kept for analysis. Airway water and heat losses were estimated using a computational model adapted to the experimental conditions and were compared with a literature-based threshold of bronchial dehydration. Eleven participants exceeded the threshold for bronchial dehydration during exercise (group A) and five did not (group B). Compared with post warm-up, the increase in cc16/cr postexercise was significant (mean increase ± SE: 0.48 ± 0.08 ng·L-1 only in group A but not in group B (mean difference ± SE: 0.10 ± 0.04 ng·L-1). This corresponds to an increase of 101 ± 32% [range: 16%-367%] in group A (mean ± SE). Our findings suggest that the use of a computational model may be helpful to estimate an individual dehydration threshold of the airways that is associated with epithelial damage during physical exercise.NEW & NOTEWORTHY Using a computational model for heat and water transfers in the bronchi, we identified a threshold in ventilation during exercise above which airway dehydration is thought to occur. When this threshold was exceeded, epithelial damage was found. This threshold might therefore represent the ventilation upper limit during exercise in susceptible individuals. Our results might help to prevent maladaptation to chronic exercise such as exercise-induced bronchoconstriction or asthma.

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.

Serum and sputum MMP-9/TIMP-1 in winter sports athletes and swimmers: relationships with airway function.

INTRODUCTION: Skiers and swimmers present characteristics of airway inflammation and remodelling of the extracellular matrix similar to what is observed in mild asthma. We aimed to compare serum and sputum MMP-9/TIMP-1 levels, to assess the balance between airway fibrogenesis and inflammation process in both categories of athletes, and to observe its seasonal variations in winter sports athletes. METHODS: We conducted a retrospective study. Winter sports athletes (n = 41), swimmers (n = 25) and healthy nonathletes (n = 10) had blood sampling, lung function measurement, skin prick tests, eucapnic voluntary hyperpnoea challenge, methacholine inhalation test, and induced sputum analysis. Twelve winter sport athletes performed the tests during both summer and winter. Serum and sputum biomarkers were measured by ELISA. RESULTS: No significant difference in serum or sputum MMP-9/TIMP-1 ratio was observed between groups, nor relationship with airway function or responsiveness. Serum MMP-9/TIMP-1 ratio was higher during the summer in winter sport athletes compared with winter season (median [Interquartile range]: 3.65 [2.47-4.03] ng.ml-1 and 1.27 [0.97-1.62] ng.ml-1, respectively, p = 0.005). Sputum MMP-9 correlated with methacholine PC20 (r = 0.45, p = 0.019) and serum cc16/SP-D ratio (r = -0.47, p = 0.013). CONCLUSION: MMP-9/TIMP-1 ratio in sputum or serum may fluctuate with training or environment but does not correlate with airway function or responsiveness in athletes.

The Specificities of Elite Female Athletes: A Multidisciplinary Approach.

Female athletes have garnered considerable attention in the last few years as more and more women participate in sports events. However, despite the well-known repercussions of female sex hormones, few studies have investigated the specificities of elite female athletes. In this review, we present the current but still limited data on how normal menstrual phases, altered menstrual phases, and hormonal contraception affect both physical and cognitive performances in these elite athletes. To examine the implicated mechanisms, as well as the potential performances and health risks in this population, we then take a broader multidisciplinary approach and report on the causal/reciprocal relationships between hormonal status and mental and physical health in young (18-40 years) healthy females, both trained and untrained. We thus cover the research on both physiological and psychological variables, as well as on the Athlete Biological Passport used for anti-doping purposes. We consider the fairly frequent discrepancies and summarize the current knowledge in this new field of interest. Last, we conclude with some practical guidelines for eliciting improvements in physical and cognitive performance while minimizing the health risks for female athletes.

Continuous exercise induces airway epithelium damage while a matched-intensity and volume intermittent exercise does not.

BACKGROUND: While continuous exercise (CE) induces greater ventilation ([Formula: see text]E) when compared to intermittent exercise (IE), little is known of the consequences on airway damage. Our aim was to investigate markers of epithelial cell damage - i.e. serum levels of CC16 and of the CC16/SP-D ratio - during and following a bout of CE and IE of matched work. METHODS: Sixteen healthy young adults performed a 30-min continuous (CE) and a 60-min intermittent exercise (IE; 1-min work: 1-min rest) on separate occasions in a random order. Intensity was set at 70% of their maximum work rate (WRmax). Heart rate (HR) and [Formula: see text]E were measured throughout both tests. Blood samples were taken at rest, after the 10th min of the warm-up, at the end of both exercises, half way through IE (matched time but 50% work done for IE) as well as 30- and 60-min post-exercise. Lactate and CC16 and SP-D were determined. RESULTS: Mean [Formula: see text]E was higher for CE compared to IE (85 ± 17 l.min- 1 vs 50 ± 8 l.min- 1, respectively; P < 0.001). Serum-based markers of epithelial cell damage remained unchanged during IE. Interaction of test × time was observed for SP-D (P = 0.02), CC16 (µg.l- 1) (P = 0.006) and CC16/SP-D ratio (P = 0.03). Maximum delta CC16/SP-D was significantly correlated with mean [Formula: see text]E sustained (r = 0.83, P < 0.001) during CE but not during IE. CONCLUSION: The 30-min CE performed at 70% WRmax induced mild airway damage, while a time- or work-matched IE did not. The extent of the damage during CE was associated with the higher ventilation rate.

Cardiorespiratory adaptation during 6-Minute Walk Test in fibrotic idiopathic interstitial pneumonia patients who did or did not respond to pulmonary rehabilitation.

BACKGROUND: Pulmonary rehabilitation (PR) improves performance in the 6-min walk test (6MWT) in a subset of patients with fibrotic idiopathic interstitial pneumonia (f-IIP); however, a large proportion of patients does not respond to PR. AIM: To investigate the effects of a PR program on cardiorespiratory responses during a 6MWT and to identify the characteristics of patients who do not show improved performance after PR. DESIGN: An observational study. SETTING: Patients were recruited from the Competence Centre for Rare Pulmonary Diseases at Lille University Hospital, France and completed an 8-week home-based PR program. POPULATION: A total of 19 patients with f-IIP; 12 with idiopathic pulmonary fibrosis (IPF) and 7 with fibrotic non-specific interstitial pneumonia. METHODS: Patients underwent spirometry and completed a 6MWT before and after an 8-week PR program. Gas exchange, heart rate, and pulse O2 saturation were measured continuously during the 6MWT. Quality of life, dyspnea, and anxiety/depression were assessed using the Short-Form 36 (SF-36), the baseline/transition dyspnea index (BDI/TDI), and the Hospital Anxiety and Depression Scale (HADS) questionnaires. RESULTS: Patients who did and did not improve the distance walked in the 6MWT by at least 30 m after PR were classified as responders (N.=9) and non-responders (N.=10), respectively. O2 uptake, ventilation rate, and distance covered during the 6MWT were significantly improved only in the responder group (P<0.05). Changes in SF-36, BDI/TDI, and HADS scores did not differ significantly between responders and non-responders. The non-responder group contained significantly more patients with IPF (P<0.05) and experienced greater arterial oxygen desaturation during the 6MWT compared with the responder group. CONCLUSIONS: Failure to improve performance in the 6MWT after PR was associated with a diagnosis of IPF, non-improvement in gas exchange, and greater arterial oxygen desaturation. CLINICAL REHABILITATION IMPACT: Most f-IIP patients who did not respond to PR were diagnosed with IPF and displayed greater hypoxemia during exercise. Clinical practitioners should seek to determine why patients fail to improve exercise performance after PR and propose an alternative exercise regimen to these patients.

Physiological comparison of intensity-controlled, isocaloric intermittent and continuous exercise.

VO2 fluctuations are argued to be an important mechanism underpinning chronic adaptations following interval training. We compared the effect of exercise modality, continuous vs. intermittent realized at a same intensity, on electrical muscular activity, muscular oxygenation and on whole body oxygen uptake. Twelve participants (24 ± 5 years; VO2peak: 43 ± 6 mL·â€…min-1·kg-1) performed (i) an incremental test to exhaustion to determine peak work rate (WRpeak); two randomized isocaloric exercises at 70%WRpeak; (ii) 1 bout of 30 min; (iii) 30 bouts of 1 min work intercepted with 1 min passive recovery. For electromyography, only the CON exercise showed change for the vastus lateralis root-mean-square (+6.4 ± 5.1%, P < .01, 95%CI 3.2, 8.3) and mean power frequency (-5.2 ± 4.8, P < .01, 95%CI -8.2, -3.5). Metabolic fluctuations (i.e. Oxygen Fluctuation Index and HHb Fluctuation Index) were higher in the intermittent modality, while post-exercise blood lactate concentrations (4.80 ± 1.50 vs. 2.32 ± 1.21 mM, respectively, for the CON and INT, P < .01, 95%CI 1.72, 3.12) and the time spent over 90% of VO2 target (1644 ± 152 vs. 356 ± 301 sec, respectively, for the CON and INT, P < .01, 95%CI 1130, 1446) were higher in the continuous modality. In conclusion, despite a similar energy expenditure and intensity, intermittent and continuous exercises showed two very different physiological responses. The intermittent modality would lead to a larger recruitment of fast twitch fibres that are less mitochondria-equipped and therefore may be more likely respondent to mitochondrial adaptations. In addition, this modality induces greater metabolic variations, a stimulus who could lead to mitochondrial development.

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.

Allergies and Exercise-Induced Bronchoconstriction in a Youth Academy and Reserve Professional Soccer Team.

OBJECTIVES: A high prevalence of respiratory allergies and exercise-induced bronchoconstriction (EIB) has been reported among endurance athletes. This study was designed to analyze the frequency of sensitization to respiratory allergens and EIB in young soccer players. DESIGN: Prospective cohort design. SETTING: Youth academy and reserve professional soccer team during the seasons 2012 to 2013 and 2013 to 2014. PARTICIPANTS: Eighty-five soccer players (mean age: 20 ± 4 years) participated. INTERVENTION: Players underwent skin prick tests (SPTs) during the seasons 2012 to 2013 and 2013 to 2014. Spirometry and a eucapnic voluntary hyperpnea test were performed on soccer players during the first season 2012 to 2013 (n = 51) to detect EIB. Two self-administered questionnaires on respiratory history and allergic symptoms (European Community Respiratory Health Survey and Allergy Questionnaire for Athletes) were also distributed during both seasons (n = 59). MAIN OUTCOME MEASURES: The number of positive SPTs, exercise-induced respiratory symptoms, presence of asthma, airway obstruction, and EIB. RESULTS: Forty-nine percent of players were sensitized to at least one respiratory allergen, 33% reported an allergic disease, 1 player presented airway obstruction at rest, and 16% presented EIB. Factors predictive of EIB were self-reported exercise-induced symptoms and sensitization to at least 5 allergens. CONCLUSIONS: Questioning players about exercise-induced respiratory symptoms and allergies as well as spirometry at the time of the inclusion medical checkup would improve management of respiratory health of soccer players and would constitute inexpensive preliminary screening to select players requiring indirect bronchial provocation test or SPTs. CLINICAL RELEVANCE: This study showed that despite low frequencies, EIB and allergies are underdiagnosed and undertreated in young soccer players.

Effect of work:rest cycle duration on [Formula: see text] fluctuations during intermittent exercise.

The succession of on-transient phases that induce a repetition of metabolic changes is a possible mechanism responsible for the greater response to intermittent training (IT). The objective of this study was to quantify [Formula: see text] fluctuations during intermittent exercise characterised by the same work:rest ratio, but different durations and identify which duration leads to the greatest fluctuations. Ten participants (24 ± 5 years; [Formula: see text]: 42 ± 7 mL·min-1·kg-1) performed (1) an incremental test to exhaustion to determine peak work rate (WRpeak) and oxygen uptake ([Formula: see text]), (2), and three 1 h intermittent exercises alternating work period at 70% WRpeak with passive recovery period of different 1:1 work:recovery duty cycles (30 s:30 s, 60 s:60 s, 120 s:120 s). [Formula: see text] response analysis revealed differences in the fluctuations across the intermittent conditions despite an identical total energy expenditure. The sum of the cycle's nadir-to-peak [Formula: see text] differences (ΣΔ[Formula: see text]) and the oxygen fluctuation index (OFI) were both greater in the 60 s:60 s condition (ΣΔ[Formula: see text]: +38% ± 13% and +19% ± 18% vs. 120 s:120 s and 30 s:30 s, P < 0.05; OFI: +41% ± 29% and +67% ± 62% vs. 120 s:120 s and 30:30 s, P < 0.05). [Formula: see text] fluctuation analysis was successful in identifying the intermittent condition associated with the greatest disturbances: the 60 s:60 s duty cycle induces more [Formula: see text] fluctuations. The present findings also demonstrate that the selection of the duty cycle duration for submaximal intermittent exercise (70% of WRpeak) prescription is of interest to produce high [Formula: see text] fluctuations.