Asthma in Competitive Cross-Country Skiers: A Systematic Review and Meta-analysis

Number of Symptoms During the Acute Phase of SARS-CoV-2 Infection in Athletes Is Associated With Multiorgan Involvement: AWARE III

OBJECTIVE

Acute respiratory infections (ARinf), including SARS-CoV-2 infection, can affect multiple organ systems that may influence return to sport (RTS) in athletes. Factors associated with multiorgan involvement in athletes with ARinf are lacking. The aim of this study was to explore whether factors such as demographics, sport participation, history of comorbidities/allergies, and number of acute symptoms are associated with multiorgan involvement in athletes with recent SARS-CoV-2 infection.

DESIGN

Prospective cohort study with cross-sectional analysis.

SETTING

Institutional clinical research facilities.

PARTICIPANTS

Ninety-five athletes (18-60 years) underwent a comprehensive medical assessment 10 to 28 days after SARS-CoV-2 infection.

INDEPENDENT FACTORS

Demographics, sport participation, history of comorbidities/allergies, and the number of acute symptoms (in 3 subgroups:1 = ≤5, 2 = 6-9, or 3 ≥ 10).

MAIN OUTCOME MEASURES

Number of organs involved in athletes with recent SARS-CoV-2 infection.

RESULTS

The number of organ systems involved was not associated with demographics (age, sex), sport participation (level and type), or history of comorbidities and allergies. However, the number of organ systems involved was significantly higher in athletes with 6 to 9 symptoms (subgroup 2) compared with those with ≤5 symptoms (subgroup 1) and this was more pronounced when comparing athletes with ≥10 symptoms (subgroup 3) with those with ≤5 symptoms (subgroup 1) (P < 0.0001).

CONCLUSIONS

Total number of acute symptoms of SARS-CoV-2 infection is related to number of organ systems involved, which is a measure of disease severity, and could therefore influence RTS decision making. Future studies should explore whether this observation holds for athletes with ARinf caused by other pathogens.

Snow sports-specific extension of the IOC consensus statement: methods for recording and reporting epidemiological data on injury and illness in sports

The International Olympic Committee's (IOC) consensus statement on 'methods for recording and reporting of epidemiological data on injury and illness in sport' recommended standardising methods to advance data collection and reporting consistency. However, additional aspects need to be considered when these methods are applied to specific sports settings. Therefore, we have developed a snow sports-specific extension of the IOC statement to promote the harmonisation of injury and illness registration methods among athletes of all levels and categories in the different disciplines governed by the International Ski and Snowboard Federation (FIS), which is also applicable to other related snow sports such as biathlon, ski mountaineering, and to some extent, para snow sports. The panel was selected with the aim of representing as many different areas of expertise/backgrounds, perspectives and diversity as possible, and all members were assigned to thematic subgroups based on their profiles. After panel formation, all members were provided with an initial draft of this extension, which was used as a basis for discussion of aspects specific to the discipline, application context, level and sex within their snow sports subgroup topic. The outcomes were then aligned with the IOC's existing consensus recommendations and incorporated into a preliminary manuscript draft. The final version of this snow sports-specific extension was developed and approved in two iterative rounds of manuscript revisions by all consensus panel members and a final meeting to clarify open discussion points. This snow sports-specific extension of the IOC statement is intended to guide researchers, international and national sports governing bodies, and other entities recording and reporting epidemiological data in snow sports to help standardise data from different sources for comparison and future research.

Global research trends in skiing from 1974 to 2023: A bibliometric analysis

This study analyzes 1643 documents related to skiing from 1974 to 2023 using the Web of Science Core Collection database, employing CiteSpace and VOSviewer for quantitative analysis. Findings reveal a growing literature output, with the past five years contributing to 36.2 % of publications. Norway leads in total publications and collaboration intensity, with the University of Salzburg and the Norwegian University of Science and Technology as prominent institutions. The research spans a wide range of disciplines such as Sport Sciences, Physiology, etc., and interdisciplinary intersections with engineering, computer science, etc. have become a future research trend. The research focuses on the analysis of skiers' sports performance, the analysis of skiing-induced sports injuries, the biomechanical analysis of skiers' postures, and the analysis of skiing-induced respiratory diseases. The study highlights the evolution of research focus from skiing injuries to injury prevention and sports performance enhancement. This comprehensive overview aids scholars in understanding skiing research hotspots and future trends efficiently.

Incidence of injury and illness at the Beijing 2022 Paralympic Winter Games held in a closed-loop environment: a prospective cohort study of 7332 athlete days

OBJECTIVE

To describe the epidemiology of injuries and illnesses sustained during the Beijing 2022 Paralympic Winter Games, organised in a closed-loop environment to adhere with COVID-19 restrictions.

METHODS

Injuries and illnesses from all teams were recorded on a daily basis by team medical staff on a web-based form and by local organising committee medical (polyclinic) facilities and venue medical support. Duplicates recorded on both systems were removed. Incidence of injuries and illnesses are reported per 1000 athlete days (95% CI).

RESULTS

564 athletes (426 male and 138 female) representing 46 countries were monitored for the 13-day period of the Beijing 2022 Paralympic Winter Games (7332 athlete days). The overall incidences were 13.0 injuries (10.6-15.8) and 6.1 illnesses (4.5-8.4) per 1000 athlete days. The incidence of injury in alpine skiing (19.9; 15.2-26.1) was significantly higher compared with Nordic skiing, ice hockey and wheelchair curling (p<0.05), while the incidence of respiratory illness was significantly higher in Nordic skiing (1.6; 0.9-2.9) compared with alpine skiing, ice hockey and snowboarding (p<0.05).

CONCLUSION

The incidence of both injury and illness at the Beijing 2022 Games were the lowest yet reported in the Paralympic Winter Games. The incidence of injury was highest in alpine skiing. These findings underscore the importance of ongoing vigilance and continued injury risk mitigation strategies to safeguard the well-being of athletes in these high-risk competitions. Respiratory illnesses were most commonly reported in Nordic skiing, which included the three cases of COVID-19 recorded at the games.

Inhaled beta2 -agonist, formoterol, enhances intense exercise performance, and sprint ability in elite cyclists

PURPOSE

Many athletes use long-acting beta2 -agonist formoterol in treatment of asthma. However, studies in non-athlete cohorts demonstrate that inhaled formoterol can enhance sprint performance calling into question whether its use in competitive sports should be restricted. We investigated whether formoterol at upper recommended inhaled doses (54 μg) would enhance sprint ability and intense exercise performance in elite cyclists.

METHODS

Twenty-one male cyclists (V̇O2max : 70.4 ± 4.3 mL × min-1  × kg-1 , mean ± SD) completed two 6-s all-out sprints followed by 4-min all-out cycling after inhaling either 54 μg formoterol or placebo. We also assessed cyclists' leg muscle mass by dual-energy X-ray absorptiometry and muscle fiber type distribution of vastus lateralis biopsies.

RESULTS

Peak and mean power output during the 6-s sprint was 32 W (95% CI, 19-44 W, p < 0.001) and 36 W (95% CI, 24-48 W, p < 0.001) higher with formoterol than placebo, corresponding to an enhancing effect of around 3%. Power output during 4-min all-out cycling was 9 W (95% CI, 2-16 W, p = 0.01) greater with formoterol than placebo, corresponding to an enhancing effect of 2.3%. Performance changes in response to formoterol were unrelated to cyclists' VO2max and leg lean mass, whereas muscle fiber Type I distribution correlated with change in sprinting peak power in response to formoterol (r2  = 0.314, p = 0.012).

CONCLUSION

Our findings demonstrate that an inhaled one-off dose of 54 μg formoterol has a performance-enhancing potential on sprint ability and short intense performance in elite male cyclists, which is irrespective of training status but partly related to muscle fiber type distribution for sprint ability.

Beyond bronchodilation: Illuminating the performance benefits of inhaled beta2 -agonists in sports

Given the prevalent use of inhaled beta2 -agonists in sports, there is an ongoing debate as to whether they enhance athletic performance. Over the last decades, inhaled beta2 -agonists have been claimed not to enhance performance with little consideration of dose or exercise modality. In contrast, orally administered beta2 -agonists are perceived as being performance enhancing, predominantly on muscle strength and sprint ability, but can also induce muscle hypertrophy and slow-to-fast fiber phenotypic switching. But because inhaled beta2 -agonists are more efficient to achieve high systemic concentrations than oral delivery relative to dose, it follows that the inhaled route has the potential to enhance performance too. The question is at which inhaled doses such effects occur. While supratherapeutic doses of inhaled beta2 -agonists enhance muscle strength and short intense exercise performance, effects at low therapeutic doses are less apparent. However, even high therapeutic inhaled doses of commonly used beta2 -agonists have been shown to induce muscle hypertrophy and to enhance sprint performance. This is concerning from an anti-doping perspective. In this paper, we raise awareness of the circumstances under which inhaled beta2 -agonists can constitute a performance-enhancing benefit.

Acute respiratory infections hamper training and competition in cross-country skiers, especially in those with asthma

Acute respiratory infections (ARinf) are one of the leading causes that prevent athletes from training and competing. The aim of this study was to investigate the burden of ARinfs during one season among cross-country skiers. All Finnish cross-country skiers enrolled in the largest national competitions in winter 2019 (n = 1282) were sent a postal questionnaire. A higher proportion of skiers with than without asthma had to refrain from competitions because of ARinf (76.9% vs. 62.2%, p = 0.011) but there was no significant difference in refraining from training (91.2% vs. 83.8%, p = 0.084). In skiers with asthma, the median duration of a single ARinf episode was longer (5.0 days, IQR 3.8-6.8 vs. 4.0 days, IQR 3.0-6.7, p  = 0.017), and they had more days of absence because of ARinf throughout the season (median 15 days (IQR 8-28) vs. 10 days (IQR 6-18), p  = 0.006) in comparison to non-asthmatics. However, many of the skiers either trained (54.4%) or competed (22.5%) during an ARinf.

Elite skiers' experiences of heat- and moisture-exchanging devices and training and competition in the cold: A qualitative survey

Background and Aims

Winter endurance athletes have a high prevalence of exercise-induced bronchoconstriction (EIB) and asthma, probably due to repeated and prolonged inhalation of cold and dry air. Heat- and moisture-exchanging devices (HME) warm and humidify inhaled air and prevent EIB. The aim of this study was to share cross-country skiers and biathletes' experiences of training and competition in low temperatures, views on temperature limits, usage of HME, and consequences of cold exposure on their health.

Methods

Eleven Swedish World Championship or Olympic medalists in cross-country skiing and biathlon were interviewed and transcripts were analyzed using qualitative content analysis.

Results

Participants described how cold temperatures predominantly affected the airways, face, and extremities. During training, extreme cold was managed by choosing warmer clothing, modification of planned sessions, use of HME, delaying training, or changing location. In competition, participants described limited possibility for such choices and would prefer adjustment of existing rules (i.e., more conservative temperature limits), especially since they understood elite skiing in low temperatures to present an occupational hazard to their health. Participants had at times used HMEs during training in cold environments but described mixed motives for their use-that HMEs warm and humidify cold inhaled air but introduce additional resistance to breathing and can cause problems due to mucus and ice build-up. Skiers also perceived that they had become more sensitive to cold during the latter part of their careers.

Conclusions

The present study gives a unique insight into the "cold" reality of being an elite athlete in skiing and biathlon. Cold exposure results in negative health consequences that are preventable, which means that rules must be followed, and organizers should acknowledge responsibility in protecting athletes from occupational hazards. Development of evidence-based guidelines for protection of athletes' respiratory health should be a focus for future translational research.

The oxygen transport cascade and exercise: Lessons from comparative physiology

Studies of animal physiology not only provide valuable knowledge for the species in question, but also offer insights into human physiology. This thought is best highlighted by the 'Krogh Principle', which states "for many problems there is an animal on which it can be most conveniently studied". This graphical review focuses on three distinct stages of the oxygen transport cascade in which human exercise physiology knowledge has been enhanced by studies carried out in animal models. We begin by exploring ventilation, and the detrimental effects of cold, dry air on the airways in two sets of elite athletes, the cross-country skier and the racing sled dog. We then discuss the transport of oxygen via hemoglobin in humans and deer mice with relatively shifted oxygen dissociation curves. Finally, we consider the technical difficulties of measuring respiratory muscle blood flow in exercising humans and how an equine model can provide an understanding of the distribution of blood flow during exercise. These cases illustrate the complementary nature of physiological studies across species.

Cross-country skiers often experience respiratory symptoms during and after exercise but have a low prevalence of prolonged cough

Background

Cross-country skiers train and compete during the winter for long periods of time in subfreezing conditions, which strains the airways and provokes respiratory symptoms. This study aimed to compare the prevalence of exercise-related symptoms and prolonged cough in competitive cross-country skiers versus the general population and to investigate the association between these symptoms and asthma.

Methods

A questionnaire was sent to Finnish cross-country skiers (n=1282) and a random sample of the general population (n=1754), with response rates of 26.9% and 19.0%, respectively.

Results

Both groups were mostly asymptomatic at rest, but symptoms were increased in both groups during and after exercise. Cough was more prevalent after exercise in skiers and phlegm production was more common during and after exercise in skiers. Asthma did not provoke specific symptoms, but symptom prevalence was higher in asthmatic individuals. Skiers had a higher prevalence of cough after exercise (60.6% vs 22.8%, p<0.001) compared with controls, but controls had a higher prevalence of prolonged cough (4.1% vs 9.6%, p=0.004). In participants without asthma, cold air triggered symptoms more often in skiers than controls, while strong odours triggered symptoms more often in asthmatic controls than skiers. Chronic cough lasting more than 8 weeks was rare, reported by 4.8% of controls and 2.0% of skiers.

Conclusion

Cross-country skiers, especially those with asthma, experience a higher burden of exercise-related respiratory symptoms compared with controls. However, repeated exposure to cold air does not appear to result in long-term hypersensitivity of the cough reflex arc.

Asthma in elite athletes - do they have Type 2 or non-Type 2 disease? A new insight on the endotypes among elite athletes

Asthma and exercise-induced bronchoconstriction are highly prevalent in elite athletes compared with the general population. Some athletes have classic asthma with allergic sensitization; however, it seems that a proportion of athletes develop asthma as a result of several years of intensive training. It leads us to believe that asthma in athletes consists of at least two distinct endotypes - classic early-onset, Type 2 mediated asthma, and asthma with later onset caused by exercise which might be classified as non-Type 2 asthma. The purpose of this review is to evaluate the current literature on asthma in athletes focusing on inflammation and examine if asthma in athletes could be characterized as either Type 2- or non-Type 2 asthma.

Differences in lung function, bronchial hyperresponsiveness and respiratory health between elite athletes competing in different sports

Objectives: Examine lung function, bronchial hyperresponsiveness (BHR) and exercise-induced respiratory symptoms in elite athletes performing different sports.Methods: Norwegian national-team athletes (30 swimmers, 32 cross-country skiers, 16 speed-skaters, 11 rowers/paddlers, 17 handball players and 23 soccer players) completed a validated questionnaire, measured exhaled nitric oxide (FE_NO), spirometry, methacholine provocation (PD_20met) and skin prick test. Three cut-off levels defined BHR; i.e., PD_20met ≤2µmol, ≤4 µmol and ≤8µmol.Results: Mean forced vital capacity (FVC) was highest in swimmers (Mean z-score[95%CI] =1.16 [0.80, 1.51]), and close to or higher than reference values according to the Global Lung Initiative equation, across all sports. Mean forced expiratory volume in 1 second (FEV₁) was higher than reference values in swimmers (0.48 [0.13, 0.84]), and ball game athletes (0.69 [0.41, 0.97]). Mean forced expiratory flow between 25 and 75% of FVC (FEF_25-75), and/or FEV₁/FVC were lower than reference values in all endurance groups. BHR defined by ≤2 and ≤8 µmol methacholine was observed in respectively 50%-87% of swimmers, 25%-47% of cross-country skiers, 20%-53% of speed-skaters, 18%-36% and of rowers/paddlers, and 0%-17% of the ball game athletes. Exercise-induced symptoms were common in all groups, most frequent in cross-country skiers (88%), swimmers (83%) and speed-skaters (81%).Conclusion: Elite swimmers and ball game athletes had higher mean FVC and FEV₁, compared to reference values. However, FEF_25-75 and/or FEV₁/FVC was lower than the reference values in all endurance groups. The prevalence of BHR was high across all sports, except the ball game athletes, and most of the athletes reported exercise-induced respiratory symptoms.

Prevalence of Asthma among Norwegian Elite Athletes

Objective

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

Methods

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

Results

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

Conclusion

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

High training volume is associated with increased prevalence of non-allergic asthma in competitive cross-country skiers

Background

Cross-country skiers have a high prevalence of asthma, but its phenotypes and association with success in competitions are not known.

Objective

To investigate, by means of a postal survey, the relative proportions of allergic and non-allergic asthma in competitive cross-country skiers compared with the general population, to study how performance level and training volume are related to asthma and its type and to assess the possible risk factors for allergic and non-allergic asthma in competitive skiers.

Methods

All Finnish cross-country skiers enrolled in the largest national competitions in winter 2019 (n=1282), and a random sample (n=1754) of the general population of the same age were sent a postal questionnaire. The response rate was 27.4% (n=351) for skiers and 19.5% (n=338) for the controls. International Ski Federation (FIS) ranking points measured the level of success in skiers. Asthma was defined as self-reported, physician-diagnosed asthma. Asthma was considered allergic if associated with doctor-diagnosed allergy, and exposure to allergens provoked asthma symptoms.

Results

The prevalence of asthma was higher in skiers than in the controls (25.9% vs 9.2%, p<0.001), and it was the highest (56.1%) in the most successful quartile of skiers. Asthma was more often non-allergic in skiers than in the controls (60.1% vs 38.7%, p=0.036). Being a skier came with a higher risk for non-allergic (OR 5.05, 95% CI 2.65 to 9.61) than allergic asthma (OR 1.92, 1.08–3.42). Using multivariable regression analysis, training volume was associated with non-allergic asthma, while age, family history of asthma and allergic rhinitis were associated with allergic asthma.

Conclusion

The prevalence of asthma is the highest in the most successful cross-country skiers. The asthma in skiers is mostly non-allergic compared with the general population of the same age. The most important risk factor for non-allergic asthma in skiers is high training volume.

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.

A breathing mask attenuates acute airway responses to exercise in sub-zero environment in healthy subjects

PURPOSE

Cold air exposure is associated with increased respiratory morbidity and mortality. Repeated inhalation of cold and dry air is considered the cause of the high prevalence of asthma among winter endurance athletes. This study assessed whether a heat- and moisture-exchanging breathing device (HME) attenuates airway responses to high-intensity exercise in sub-zero temperatures among healthy subjects.

METHODS

Using a randomized cross-over design, 23 healthy trained participants performed a 30-min warm-up followed by a 4-min maximal, self-paced running time trial in - 15 °C, with and without HME. Lung function was assessed pre- and immediately post-trials. Club cell protein (CC-16), 8-isoprostane, and cytokine concentrations were measured in plasma and urine pre- and 60 min post trials. Symptoms were assessed prior to, during, and immediately after each trial in the chamber.

RESULTS

HME use attenuated the decrease in forced expiratory volume in 1 s (FEV₁) post trials (∆FEV₁: mean (SD) HME - 0.5 (1.9) % vs. no-HME - 2.7 (2.7) %, p = 0.002). HME also substantially attenuated the median relative increase in plasma-CC16 concentrations (with HME + 27% (interquartile range 9-38) vs no-HME + 121% (55-162), p < 0.001) and reduced airway and general symptom intensity, compared to the trial without HME. No significant changes between trials were detected in urine CC16, 8-isoprostane, or cytokine concentrations.

CONCLUSION

The HME attenuated acute airway responses induced by moderate-to-maximal-intensity exercise in - 15 °C in healthy subjects. Further studies are needed to examine whether this HMEs could constitute primary prevention against asthma in winter endurance athletes.

Overuse of Short-Acting Beta-2 Agonists (SABAs) in Elite Athletes: Hypotheses to Explain It

The use of short-acting beta-2 agonists (SABAs) is more common in elite athletes than in the general population, especially in endurance sports. The World Anti-Doping Code places some restrictions on prescribing inhaled β2-agonists. These drugs are used in respiratory diseases (such as asthma) that might reduce athletes’ performances. Recently, studies based on the results of the Olympic Games revealed that athletes with confirmed asthma/airway hyperresponsiveness (AHR) or exercise-induced bronchoconstriction (EIB) outperformed their non-asthmatic rivals. This overuse of SABA by high-level athletes, therefore, raises some questions, and many explanatory hypotheses are proposed. Asthma and EIB have a high prevalence in elite athletes, especially within endurance sports. It appears that many years of intensive endurance training can provoke airway injury, EIB, and asthma in athletes without any past history of respiratory diseases. Some sports lead to a higher risk of asthma than others due to the hyperventilation required over long periods of time and/or the high environmental exposure while performing the sport (for example swimming and the associated chlorine exposure). Inhaled corticosteroids (ICS) have a low efficacy in the treatment of asthma and EIB in elite athletes, leading to a much greater use of SABAs. A significant proportion of these high-level athletes suffer from non-allergic asthma, involving the th1-th17 pathway.

Higher prevalence but later age at onset of asthma in cross-country skiers compared with general population

Cross-country skiing causes strain in the airways because skiers train and compete in cold air. The aim of this survey was to investigate the prevalence and age at onset of asthma, asthma control, and use of asthma medication in Finnish competitive cross-country skiers. All cross-country skiers who were enrolled in the largest national competitions in winter 2019 (n = 1282) were invited to the study via the Finnish Ski Association. A control group (n = 1733) was matched for the responding skiers by age, gender, and region. The response rate was 27.4% (n = 351) for skiers and 19.5% (n = 338) for the controls. The prevalence of asthma was 25.9% in skiers and 9.2% in the controls (p < 0.001). Median (IQR) age at first asthma-related symptoms was higher in skiers than in the controls (13.0 (8.25-16.0) vs. 8.0 (2.25-11.75) years, p < 0.001), and the difference in asthma prevalence was evident only after the start of skiing career. Median (IQR) Asthma Control Test (ACT) score in skiers and controls with asthma was 22.0 (21-24) vs. 22.0 (19-24) (p = 0.611), and 89.0% of skiers and 77.4% of controls had well-controlled asthma (ACT score ≥20). In skiers with asthma, 82.4% used regular inhaled corticosteroids (ICS), and 80.2% used bronchodilators. A fixed combination of ICS +long-acting β2-agonist was regularly used by 47.3% of the skiers and 22.6% of the controls with asthma (p = 0.016). In conclusion, asthma prevalence is about 2.5 times higher, and age at onset of asthma is later in skiers compared with the controls. Asthma in cross-country skiers is mostly well controlled and on regular maintenance treatment.

A heat and moisture-exchanging mask impairs self-paced maximal running performance in a sub-zero environment

Purpose

Heat-and-moisture-exchanging devices (HME) are commonly used by endurance athletes during training in sub-zero environments, but their effects on performance are unknown. We investigated the influence of HME usage on running performance at − 15 °C.

Methods

Twenty-three healthy adults (15 male, 8 female; age 18–53 years; \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text O}_{2peak}$$\end{document}V˙O2peak men 56 ± 7, women 50 ± 4 mL·kg⁻¹·min⁻¹) performed two treadmill exercise tests with and without a mask-style HME in a randomised, crossover design. Participants performed a 30-min submaximal warm-up (SUB), followed by a 4-min maximal, self-paced running time-trial (TT). Heart rate (HR), respiratory frequency (f_R), and thoracic area skin temperature (T_sk) were monitored using a chest-strap device; muscle oxygenation (SmO₂) and deoxyhaemoglobin concentration ([HHb]) were derived from near-infra-red-spectroscopy sensors on m. vastus lateralis; blood lactate was measured 2 min before and after the TT.

Results

HME usage reduced distance covered in the TT by 1.4%, despite similar perceived exertion, HR, f_R, and lactate accumulation. The magnitude of the negative effect of the HME on performance was positively associated with body mass (r² = 0.22). SmO₂ and [HHb] were 3.1% lower and 0.35 arb. unit higher, respectively, during the TT with HME, and T_sk was 0.66 °C higher during the HME TT in men. HR (+ 2.7 beats·min⁻¹) and T_sk (+ 0.34 °C) were higher during SUB with HME. In the male participants, SmO₂ was 3.8% lower and [HHb] 0.42 arb. unit higher during SUB with HME.

Conclusion

Our findings suggest that HME usage impairs maximal running performance and increases the physiological demands of submaximal exercise.