Self-reported obstructive airway symptoms are common in young cross-country skiers

The reported high use of anti-asthmatic drugs in cross-country skiers prompted a study to assess the prevalence of self-reported asthma, asthma-associated symptoms and the use of anti-asthmatic medication among cross-country skiers. A self-administered questionnaire based on the Medical Research Council questionnaire was answered by cross-country skiers in the Swedish national ski team, in upper secondary school ski-classes and in the Swedish army ( n =305). Controls ( n =141) were pupils from regular classes in the same upper secondary schools. Skiers more often gave posi- tive answers to all questions on asthma and asthma-associated symptoms. The cumulative prevalence of asthma was 15% in skiers and 6% in controls. We conclude that the common use of anti-asthmatic drugs among cross-country skiers reflects a high prevalence of self-reported asthma and asthma-associated symptoms. The causes of these differences are un-known.     

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

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

Prevalence,age at onset,and risk factors of self‐reported asthma among Swedish adolescent elite cross‐country skiers

The objective of the study was to compare the prevalence of self‐reported physician‐diagnosed asthma and age at asthma onset between Swedish adolescent elite skiers and a reference group and to assess risk factors associated with asthma. Postal questionnaires were sent to 253 pupils at the Swedish National Elite Sport Schools for cross‐country skiing, biathlon, and ski‐orienteering (“skiers”) and a random sample of 500 adolescents aged 16‐20, matched for sport school municipalities (“reference”). The response rate was 96% among the skiers and 48% in the reference group. The proportion of participants with self‐reported physician‐diagnosed asthma was higher among skiers than in the reference group (27 vs 19%, P =.046). Female skiers reported a higher prevalence of physician‐diagnosed asthma compared to male skiers (34 vs 20%, P =.021). The median age at asthma onset was higher among skiers (12.0 vs 8.0 years; P <.001). Female sex, family history of asthma, nasal allergy, and being a skier were risk factors associated with self‐reported physician‐diagnosed asthma. Swedish adolescent elite cross‐country skiers have a higher asthma prevalence and later age at asthma onset compared to a reference population. Being an adolescent, elite skier is an independent risk factor associated with asthma.     

Self-reported health, physical activity and prevalence of complaints in elite cross-country skiers and matched controls

AIM: The purpose of this study was to compare physical health, physical activity and location for possible symptoms in high school students with cross-country skiers of the same age from ski high schools. Another aim was to study back pain with regards to influence on skiing. METHODS: The subjects studied were: 92% (n=120) of all Swedish cross-country skiers at ski high schools and 68% (n=993) of regular high school students from the North part of Sweden answered a reliable questionnaire (r=1) with regards to health, physical activity and location of possible symptoms/injuries during the last 3 months. Furthermore, the skiers answered questions on possible ski related back pain. RESULTS: All skiers were active also in other sports compared with 26% of the controls and at considerably higher levels of physical effort than the controls; 92% of the skiers and 76% of the controls described themselves as healthy, meaning 'very good' or 'good' (P=0.0001); 55% of the skiers and 64% of the controls reported recent symptoms (P=0.06); 47% of the skiers reported previous or present complaints of back pain, mainly low back pain, which could be relieved by changing body position from a flexed to a more extended one while skiing, and 77% reported their back pain to disappear during rest. CONCLUSIONS: These results show the need for encouraging regular high school students to participate in sport. It also shows the importance of introducing preventative strategies regarding back pain to long-distance cross-country skiers, who are exposed to a prolonged flexed position of their back.     

Asthma is more prevalent in elite swimming adolescents despite better mental and physical health

An increased risk of developing asthma has been reported among swimmers exposed to chloramine in pool arenas. The aim of the present study was to compare the prevalence of asthma and respiratory symptoms among elite aspiring swimmers compared with age‐matched controls with different degrees of physical activity. We also aimed to relate these findings to mental and psychosocial factors. One hundred and one elite swimmers and 1628 age‐matched controls answered a questionnaire containing questions about respiratory symptoms, lifestyle factors, mental and physical well‐being. The controls were divided into three different groups according to the degree of physical activity, no physical activity, recreational training and elite training. Swimmers reported significantly more asthma symptoms, with 36.6% having physician‐diagnosed asthma, compared with 16.2% among the controls. Use of regular medication was more common (14.9% vs 8.0%) and more swimmers reported an exacerbation of their asthma during the previous 12 months (16.8%) vs (5.8%) for the controls. Despite an increased prevalence of asthma symptoms, the swimmers reported best physical performance and best mental and physical well‐being. They also had a healthier lifestyle without smoking and low alcohol consumption.     

A 10-year follow-up study of pulmonary function in symptomatic elite cross-country skiers--athletes and bronchial dysfunctions

A high prevalence of asthma-like symptoms and abnormal bronchial reactivity to various stimuli has been reported among endurance athletes. This report presents the cases of three cross-country skiers who have shown a progressive development of airway obstruction during their sport careers. The observed decline in FEV1, FEV1/FVC and/or FVC (FEV, forced expiratory volume; FVC, forced expiratory vital capacity) was greater than expected from longitudinal regression equations describing the ageing effect on pulmonary function. The three subjects encountered abnormal respiratory discomfort during their sport activity which was not systematically associated with abnormal bronchial reactivity (either to methacholine or exercise hyperventilation). At the end of the follow-up periods (9-12 years), all three skiers presented objective signs of airflow limitations during intense exercise. This report suggests that repeated chronic hyperventilation of cold dry air in cross-country skiers for several years can induce permanent bronchial disorders which may include remodeling processes and induce ventilatory limitations during intense exercise.     

Prevalence of asthma-like symptoms, asthma and its treatment in elite athletes

The objective was to determine the prevalence of asthma-like symptoms and asthma and the use of asthma medication in Danish elite athletes. A cross-sectional questionnaire survey of Danish elite athletes was conducted in 2006. All elite athletes ( N =418) financially supported by the national organization of elite athletes comprised the study group; 329 (79%) completed the questionnaire concerning their sport, asthma-like symptoms, asthma and use of asthma medication. Asthma-like symptoms at rest were reported by 41% of respondents; 55% reported asthma-like symptoms at rest or at exercise. Physician-diagnosed asthma was present in 16% and 14% had current asthma. Asthma medication was taken by 7% of the athletes, of whom 79% used inhaled corticosteroids and 21% used inhaled β₂-agonists only. Athletes participating in endurance sports had higher prevalences of current asthma (24%) and use of asthma medication (15%) than all other athletes ( P <0.01). Athletes participating in endurance sports have a higher prevalence of asthma and use of asthma medication. The frequency of asthma medication is lower than the prevalence of current asthma indicating that there is no overuse of asthma medication among Danish elite athletes.     

Sports in extreme conditions: The impact of exercise in cold temperatures on asthma and bronchial hyper-responsiveness in athletes

Exercise-induced asthma (EIA) and bronchial hyper-responsiveness (BHR) are frequently reported among elite athletes of outdoor endurance winter sports, particularly in cross-country and biathlon skiers. The pathogenesis of EIA is related to water loss and heat-loss through the increased respiration during exercise, leading to mediator release, airways inflammation and increased parasympathetic nervous activity in the airways, causing bronchial constriction and BHR. In the competing elite athlete this is presently considered to be due to the frequently repeated increased ventilation during training and competitions in combination with the repeated environmental exposure to cold air in outdoor winter sports. It is important that athletes at risk of asthma and BHR are monitored through regular medical control with assessment of lung function and BHR, and when BHR or asthma is diagnosed, optimal controlling treatment through anti-inflammatory treatment by inhaled steroids should be started and relieving treatment (inhaled ipratropium bromide and inhaled β2-agonists) should be used to relieve bronchial constriction if present.     

Bronchial hyperresponsiveness in skiers: field test versus methacholine provocation?

INTRODUCTION: Asthma is frequently reported in endurance athletes, particularly in cross-country skiers. It has been reported that an exercise field test performed with the competitive type of exercise is the better for diagnosing asthma and bronchial hyperresponsiveness in athletes than bronchial provocation with methacholine. OBJECTIVE: The main objective was to compare an exercise field test consisting of a skiing competition with methacholine bronchial provocation in the diagnosis of asthma and bronchial hyperresponsiveness among skiers. METHODS: Twenty-four elite cross-country skiers from the Norwegian national teams (males/females = 16/8) were included in the study. The cumulative dose of inhaled methacholine causing a 20% fall in forced expiratory volume in 1 s (FEV1) (PD20) was compared with reduction in lung function (FEV1) >or= 10% from before to after an exercise field test consisting of a cross-country skiing competition, 10 km (males) and 7 km (females), respectively. RESULTS: Nine out of 24 (37.5%) athletes experienced a positive methacholine test (PD20 < 8 micromol) (2 females and 7 males), whereas only 2 of the 24 subjects (8.3%) had reductions in FEV1 >or= 10% after the exercise field test. A significant negative correlation was found between age and bronchial responsiveness, r = -0.47, P = 0.02. CONCLUSION: The methacholine bronchial provocation test is more sensitive than a sport specific exercise field test for identifying athletes with asthma and/or bronchial hyperresponsiveness.     

The prevalence and impact of respiratory symptoms in asthmatics and nonasthmatics during deployment

OBJECTIVE: The purpose of this study was to compare the prevalence, severity, and impact of respiratory symptoms in asthmatics and nonasthmatics during Operation Enduring Freedom and Operation Iraqi Freedom. METHODS: A survey was given to 1,250 active duty soldiers and Department of Defense contractors returning from Operation Enduring Freedom/Operation Iraqi Freedom. Subjects were asked about demographics, smoking habits, respiratory symptoms, and impact on job performance before and during deployment. Patients with a history of asthma were asked method of diagnosis, current symptoms, and asthma therapy. RESULTS: A total of 1,193 subjects returned the completed questionnaire (95% response rate). Mean age of respondents was 38 +/- 11 years, 83% (n = 977) were male, and 31% (n = 375) were past or present smokers. Sixty-one subjects (5%) reported a previous diagnosis of asthma. Both asthmatics and nonasthmatics had increased respiratory symptoms of wheezing, cough, sputum production, chest pain/tightness, and allergy symptoms during deployment compared to predeployment (p < 0.05 for all). When compared to nonasthmatics, asthmatic subjects reported more wheezing, sputum production, and chest pain/tightness during deployment (p < 0.0001, 0.05, 0.05 respectively), had more difficulty with military duties (p < 0.05), and were more likely to seek medical attention and receive duty restrictions (p < 0.0001). Twenty-six percent (n = 16) of asthmatics reported poor baseline symptom control, and this group had significantly increased symptoms, functional limitations, and health care utilization when compared to asthmatics who were symptom-controlled at baseline. CONCLUSIONS: Respiratory symptoms were common among both asthmatics and nonasthmatics during deployment. Differences in symptoms and health care utilization in this group of asthmatics were primarily due to subjects with poor baseline control.     

Asthma in adolescent athletes

Athletes active in endurance sports are at an increased risk of acquiring asthma through their sports activities, especially so for cross-country skiers, biathlon skiers, swimmers and athletes of other endurance sports. Asthma may be present from early childhood or develop while in active sports. This article focuses on the physical activity and sports activities in children and adolescents. Exercise-induced asthma (EIA) is found in 8-10% of a normal child population of school age and in about 35% of children with current asthma. EIA is caused by the markedly increased ventilation during exercise, with increased heat and water loss through respiration, leading to bronchial constriction. The risk of developing asthma in the young athlete is related to the repeated daily training activity with increased epithelial damage of the airways, delayed repair due to the daily repetition of the training and increased airway mucosal inflammation. The increased environmental exposure through the sports activity to environmental agents, such as cold, dry air in skiers and chlorine compounds in swimmers, increases symptoms and signs of asthma and bronchial hyper-responsiveness, either worsening an existing asthma or leading to a novel disease in a previously healthy athlete. Several specific aspects of daily training life, environmental exposure, diagnostic procedures and aspects of treatment related to the regulations of medication use in sports need particular attention when addressing the adolescent athlete with respiratory symptoms.     

Respiratory tract infection and bronchial responsiveness in elite athletes and sedentary control subjects

To assess the effect of physical exercise during an acute respiratory tract infection (RTI) on bronchial responsiveness, methacholine bronchial challenge tests were performed prospectively in 19 nonasthmatic male crosscountry skiers and 22 healthy control subjects with minimal physical activity. Twelve skiers and 10 controls contracted RTI and were studied before and 1, 3 and 6 weeks after the onset of symptoms. The skiers were given no restrictions in their training routines during the period of illness. The geometric mean provocation concentration of methacholine causing a 10% fall in the forced expiratory volume in the first second (PC₁₀), was lower 1 week after onset of infection than at the initial test in the skiers. From the level at 1 week, PC₁₀ increased to levels at 3 and 6 weeks after infection. The PC₁₀ values at 3 and 6 weeks were not significantly different from the initial test. No significant changes in PC₁₀ occurred after infection in the control group. No significant changes in pulmonary function tests were found during the study period in either of the two groups. In conclusion, RTI was associated with a transient increase in bronchial responsiveness in athletes performing physical training during the symptomatic period of respiratory illness but not in nonactive control subjects.     

Prevalence of asthma and atopy in Italian Olympic athletes

This study aimed to assess the prevalence of asthma and atopy in the Italian athletes who were trying for a position on the Italian Olympic team for the 2000 Sydney Olympic Games. Overall, 1060 athletes (mean age 24 years, range 15 - 69 years, 729 males) were recruited and divided into three groups of sport activities: 1) anaerobic, 2) aerobic-anaerobic, 3) aerobic. Asthmatic and atopic athletes were identified by a self-administered, standardized questionnaire modified from the ISAAC questionnaire. Spirometry was performed in the athletes who reported wheezing or asthma and in an equal number of randomly selected controls. Athletes reporting wheezing or asthma were 15 %. However, only a minority of asthmatics had moderate or severe disease: indeed, 2.5 % reported more than 4 attacks in the last year. The prevalence of atopy was 18 %. Asthma was more common in athletes engaged in aerobic sport activities than in the other groups. Asthmatic athletes had a significantly lower value of some spirometric parameters in comparison with the control group. In conclusion, the prevalence of wheezing or asthma in a large sample of Italian competitive athletes was found higher than in general population; respiratory symptoms were more prevalent in athletes engaged in aerobic sport activities; a significant impairment of lung function was found in athletes suffering from mild and rarely symptomatic asthma.     

Winter sports athletes: long-term effects of cold air exposure

Athletes such as skaters and skiers inhale large volumes of cold air during exercise and shift from nasal to mouth breathing. Endurance athletes, like cross-country skiers, perform at 80% or more of their maximal oxygen consumption and have minute ventilations in excess of 100 l/min. Cold air is always dry, and endurance exercise results in loss of water and heat from the lower respiratory tract. In addition, athletes can be exposed to indoor and outdoor pollutants during the competitive season and during all-year training. Hyperpnoea with cold dry air represents a significant environmental stress to the airways. Winter athletes have a high prevalence of respiratory symptoms and airway hyper-responsiveness to methacholine and hyperpnoea. The acute effects of exercise in cold air are neutrophil influx as demonstrated in lavage fluid and airway epithelial damage as demonstrated by bronchoscopy. Upregulation of pro-inflammatory cytokines has been observed in horses. Chronic endurance training damages the epithelium of the small airways in mice. Airway inflammation has been observed on bronchoscopy of cross-country skiers and in dogs after a 1100-mile endurance race in Alaska. Neutrophilic and lymphocytic inflammation with remodelling is present in bronchial biopsies from skiers. Repeated peripheral airway hyperpnoea with dry air causes inflammation and remodelling in dogs. As it is currently unknown if these airway changes are reversible upon cessation of exposure, preventive measures to diminish exposure of the lower airways to cold air should be instituted by all winter sports athletes.     

Radiographic abnormalities in the thoracolumbar spine of young elite skiers

An increased frequency of radiologic abnormalities in the thoracolumbar spine has been reported among young athletes in various sports, but there are no data concerning ski sports. To evaluate the incidence of these abnormalities in young elite skiers, we compared 120 skiers younger than 17 years old (alpine skiers, ski jumpers, and Nordic cross-country skiers) with a random sample of 39 control subjects of the same age who had no history of high-performance sports participation. Standardized anteroposterior and lateral radiographs of the entire lumbar spine, the lower thoracic spine, and the upper part of the sacrum were obtained from each athlete and each control subject. Radiographs were evaluated by two independent observers for the presence and size of anterior and posterior endplate lesions and Schmorl's nodes. The elite alpine skiers and ski jumpers demonstrated a significantly higher rate of anterior endplate lesions than did the control subjects. This finding might be attributable to excessive loading and repetitive trauma of the immature spine under high velocity, especially in the forward bent posture.     

Effect of reinfusion of autologous blood on exercise performance in cross-country skiers

The effect of reinfusion of autologous blood (1350 ml) on exercise time over a specified distance (approx. 15 km) 4 weeks after phlebotomy ("blood doping") were investigated in six well-trained cross-country skiers. An additional control group of six well-trained skiers was included in the study. Test races were performed before phlebotomy, 3 h after, and 14 days after reinfusion of blood. In each test race, the mean time of the control group was set to 100% and the time of the blood-doped subjects expressed in percentage of the control group mean time. In the first control race, the mean time of the subjects who were later "blood doped" was 99.4% of the control group. However, both 3 h and 14 days after the reinfusion of autologous blood, the mean time of the blood-doped subjects was significantly lower (94.1%; P less than 0.05; 96.3%, P less than 0.05, respectively) than the control group. In conclusion, reinfusion of autologous blood stored in a refrigerator for 4 weeks after phlebotomy significantly increased performance expressed as race time in cross-country skiers. The significantly increased performance was observed both 3 h and 14 days after reinfusion.     

Asthma in Tunisian elite athletes

Several studies in the past few decades have shown that very intense and repeated exercise, particularly when performed over many years, could cause respiratory health problems. The prevalence of exercise-induced asthma has increased in the athletic population, particularly in elite athletes and has not been published in North African athletes. The aim of this study was to determine the prevalence of exercise-induced asthma and/or exercise-induced bronchoconstriction in Tunisian elite athletes. Each participant responded to a questionnaire about respiratory symptoms and medical history and underwent a resting spirometry testing before exercise. Exercise-induced bronchoconstriction was defined as a decrease of at least 15% in pre-exercise forced expiratory volume in one second at any time point after exercise. Post-exercise spirometry revealed the presence of exercise induced bronchoconstriction in 14 out of 107 (13%) elite athletes, while only 1.8% of the subjects reported having previously diagnosed asthma. The prevalence of exercise-induced bronchoconstriction was 19% (8/42) among those athletes training outdoors and 10% (6/65) among those training indoors. In conclusion, our findings indicate that a significant number of Tunisian athletes had exercise-induced bronchoconstriction while not diagnosed before.     

Prévalence de l'asthme chez l'athlète,influence de la discipline sportive et des conditions environnementales

Purpose – To assess the prevalence of asthma (PA) in competitive athletesMethods – PA was studied in 530 athletes of a regional to an international caliber (cross country-skiers, cyclists, alpine skiers and judokas) on the basis of a specific questionnaire and a reversible airway obstruction.Results – Classified from the lowest to the highest, the PA according to sport was the following : judo, cross-country skiing, alpine skiing, and cycling.Conclusion – These results confirmed the PA is low in athletes who hyperventilate moderatly and are usually sheltered from cold temperatures. Although the PA of skiers (16%) was similar to that reported by other studies the high proportion of allergic asthma (60–80%) suggests a profile different from that reported in this subpopulation by others i.e. non atopic “asthma skiers”. The greater duration of cold exposure in the alpine skier group despite lower ventilatory requirements may account for its greater PA compared to that of the cross-country skiers. Finally, the higher PA of the cyclist group may be explained by the conjunction between the hyperventilation, exposure to aerocontaminants and possibly to cold.     

Back injuries and pain in adolescents attending a ski high school

This study compared overuse injuries, small abnormalities, and pain alone in different types of skiing and activity levels. Subjects were 45 ski high school athletes aged 15–19 years. We found the back and knees significantly more prone to activity-related injuries and pain than other body regions. Thirty subjects (67%) had low back pain on the first examination, and 17 had pain caused by overuse of the back. This was more frequent among active, young competitive boys in the cross-country skiing group, with mature height less than 99%, than among noncompetitive boys in the same group or among the alpine skiers. Neck pain was reported only by girls. Eight subjects had low back pain related to small abnormalities. The subjects were given counseling about training and physiotherapy. The 1-year follow-up found a significant reduction in back pain due to overuse injuries (from 17 to 3 subjects) and indistinct neck pain (from 10 to 2) but no reduction in pain in those with small abnormalities in the low back. Low back pain was common in young athletes, particularly in cross-country skiers. Excessively rapid progression of training and faulty technique increased back pain complaints from 36% when entering the school to 67% at the first examination. A proper evaluation and treatment of overuse injuries and accurate counseling of training types, volume, and progression reduced the low back pain problems to 29% of subjects 1 year later in spite of a maintained high activity level. A minimum entrance requirement to conditioning seems mandatory for students attending a ski high school.     

Iron status in elite skiers

The iron status of 54 male and 30 female elite skiers (biathlon, alpine and cross-country skiers) was studied during snow training and compared with that of relevant control groups. There was no significant difference between skiers and controls in mean Hb, serum ferritin, total iron-binding capacity, frequency of iron deficiency or anemia. Iron deficiency was found in 4 women (1 of whom was anemic) and 1 man, all in the cross-country group. The urinary iron concentration, investigated 1 day after hard cross-country training in 29 skiers, did not differ from that of a control group. In a separate study, 13 cross-country skiers were followed with repeated tests during a whole year. No change was seen in their iron status. Our results show that the iron status of both endurance and alpine skiers is comparable to that of a normal population and that there is no need for routine iron supplementation.