Trine Stensrud

Respiratory symptoms and bronchial responsiveness in competitive swimmers.

PURPOSE A high prevalence of bronchial hyperresponsiveness (BHR) and respiratory symptoms has been reported among competitive swimmers. From the 2002 Winter Olympics, BHR measurements or bronchodilator reversibility have been required for approved use of β2-agonists in sports. The first aim of this study was to evaluate the relationship among respiratory symptoms in young elite swimmers, eucapnic voluntary hyperpnea (EVH), and the inhaled dose of methacholine, causing a 20% decrease in forced expiratory volume in 1 s (FEV1; PD(20 methacholine)). The second aim of this study was to assess the repeatability of the EVH test. METHODS For this study, 15 male and 9 female adolescent elite swimmers, aged 15 to 25 yr, performed one PD(20 methacholine) test and two EVH tests in a randomized order. Dry air containing 5% CO2 was inhaled for 6 min with a target ventilation of ≥85% of maximum voluntary ventilation (minimum = 65%). PD(20 methacholine) ≤2 μmol and EVH with FEV1 reduction ≥10% were considered positive. Respiratory symptoms and medication were reported in the modified AQUA2008 questionnaire. RESULTS Twenty swimmers (83%) reported respiratory symptoms, 13 (65%) of them had a positive provocation test. Fourteen (58%) had at least one positive test to either EVH or PD(20 methacholine); three had only one positive EVH test. One athlete had BHR without symptoms. The sensitivity of PD(20 methacholine) ≤2 μmol for respiratory symptoms was 50% versus 60% and 47.37% for the two EVH tests, respectively, and 75% for PD(20 methacholine) ≤4 μmol. The Bland-Altman plot of the two EVH tests showed a consistent distribution, with only one subject outside the limits of agreement. CONCLUSIONS BHR was frequently found among adolescent competitive swimmers. PD(20 methacholine) ≤2 μmol and EVH ≥ 10% compared well, but PD(20 methacholine) ≤4 μmol had the highest sensitivity for respiratory symptoms. The EVH test has high repeatability but is very expensive and uncomfortable to perform.

Two distinct phenotypes of asthma in elite athletes identified by latent class analysis

Abstract Introduction: Clusters of asthma in athletes have been insufficiently studied. Therefore, the present study aimed to characterize asthma phenotypes in elite athletes using latent class analysis (LCA) and to evaluate its association with the type of sport practiced. Methods: In the present cross-sectional study, an analysis of athletes’ records was carried out in databases of the Portuguese National Anti-Doping Committee and the Norwegian School of Sport Sciences. Athletes with asthma, diagnosed according to criteria given by the International Olympic Committee, were included for LCA. Sports practiced were categorized into water, winter and other sports. Results: Of 324 files screened, 150 files belonged to asthmatic athletes (91 Portuguese; 59 Norwegian). LCA retrieved two clusters: “atopic asthma” defined by allergic sensitization, rhinitis and allergic co-morbidities and increased exhaled nitric oxide levels; and “sports asthma”, defined by exercise-induced respiratory symptoms and airway hyperesponsiveness without allergic features. The risk of developing the phenotype “sports asthma” was significantly increased in athletes practicing water (OR = 2.87; 95%CI [1.82–4.51]) and winter (OR = 8.65; 95%CI [2.67–28.03]) sports, when compared with other athletes. Conclusion: Two asthma phenotypes were identified in elite athletes: “atopic asthma” and “sports asthma”. The type of sport practiced was associated with different phenotypes: water and winter sport athletes had three- and ninefold increased risk of “sports asthma”. Recognizing different phenotypes is clinically relevant as it would lead to distinct targeted treatments.

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.

Bronchial nitric oxide flux and alveolar nitric oxide concentration after exposure to hyperoxia.

BACKGROUND The fraction of nitric oxide in exhaled gas (FE(NO)) is reduced by 30-70% after exposure to partial pressures of oxygen (Po2) of 200-240 kPa for 90 min. The purpose of this study was to partition FE(NO) into its flow-independent alveolar and bronchial components. A reduced bronchial NO flux (JawNO) is associated with induced bronchoconstriction, while increased alveolar NO concentration (C(A)NO) is associated with increased alveolar dead space. METHODS There were 12 patients undergoing hyperbaric oxygen (HBO) therapy for 90 min at a Po2 of 240 kPa and 20 healthy subjects exposed to normobaric hyperoxia (NBO) breathing 100% oxygen for 90 min who were compared to a control group of 6 subjects breathing ambient air. FE(NO) was measured at flow rates from 30 to 250 ml x s(-1) before and after the exposures and the Högman Märilainen algorithm was used to calculate JawNO and C(A)NO. RESULTS FE(NO) at an expiratory flow rate of 50 ml x s(-1) was reduced from 17.6 +/- 8.3 to 12.3 +/- 6.3 ppb after HBO exposure and from 17.8 +/- 6.2 to 13.3 +/- 5.2 ppb after NBO exposure. There was a significant reduction in JawNO, but unchanged C(A)NO. There were no changes in the control experiment. DISCUSSION The reduction in FE(NO) after exposure to normobaric and hyperbaric hyperoxia appears to be predominantly an airway effect. An unchanged and low C(A)NO indicate preserved integrity of the gas exchange units without increased alveolar dead space at rest.

Parasympathetic activity and bronchial hyperresponsiveness in athletes

PURPOSE A high prevalence of asthma and bronchial hyperresponsiveness (BHR) is reported in swimmers and cross-country skiers. It has been suggested that increased parasympathetic nervous activity is involved in asthma development in endurance athletes. We aimed to assess the associations of BHR to parasympathetic activity in healthy and asthmatic swimmers and cross-country skiers and healthy nonathletes. METHODS Parasympathetic activity was measured by pupillometry and heart rate variability at the onset of exercise with the cardiac vagal index calculated in 28 cross-country skiers (♂18/♀10), 29 swimmers (♂17/♀12), and 30 healthy nonathlete controls (♂14/♀16) on two different days. All subjects performed a methacholine bronchial challenge with the provocation dose causing 20% decrease in the forced expiratory volume in 1 s calculated (PD20met). Data were analyzed by robust regression analysis and presented as β coefficients with 95% confidence intervals (CI). RESULTS PD20met was negatively associated with cardiac vagal index (-13.9, 95% CI = -26.8 to -1.0) in all subjects. When adjusted to the type of sport, this association was stronger in swimmers (-8.3, 95% CI = -13.0 to -3.6) as compared with controls and nonsignificant in cross-country skiers. Percent pupil constriction was significantly associated with PD20met in swimmers (-9.4, 95% CI = -15.4 to -3.4) only after adjusting for the type of sport. Fourteen swimmers (48%) and 16 cross-country skiers (57%) had doctor-diagnosed asthma in combination with current BHR and/or current use of asthma drugs. Seventy-two percent swimmers, 44% cross-country skiers, and 39% controls had a PD20met ≤8 μmol (P = 0.015). Fourteen swimmers had a PD20met ≤2 μmol as compared with one cross-country skier (P < 0.001). CONCLUSION Parasympathetic activity measured in the heart is more closely related to BHR as compared with parasympathetic activity measured in the pupils. The type of sport influences BHR severity and its relationship to parasympathetic activity.

Increased bronchial parasympathetic tone in elite cross-country and biathlon skiers: a randomised crossover study

This article has been retracted.

Asthma in medium altitude - exercise-induced bronchoconstriction in hypobaric environment in subjects with asthma

Background:  Hypoxic gas inhalation has been reported to enhance airway responsiveness and results in bronchoconstriction in animal models and in humans with asthma. However, the data have so far been conflicting. The aim of the present study was to examine the effect of reduced barometric pressure on exercise‐induced bronchoconstriction (EIB) in subjects with asthma.

Young female handball players and sport specialisation: how do they cope with the transition from primary school into a secondary sport school?

Objective The aim of the present study was to examine how six young female handball players (aged 13–14 years) perceived the transition from primary school to a sport-specialised secondary school. Methods Physical and physiological data as well as data from questionnaires were collected at baseline and after the first year at the sport school, and qualitative interviews were performed retrospectively after the first year at school. Results Evidence of competition-related stressors, organisational stressors (sport and school balance) and personal stressors (social life and sport balance, lack of sleep and severe injuries) was found. Three girls developed long-lasting musculoskeletal injuries (>3 months out of ordinary training) and one experienced repeated short periods (≤2 weeks out of ordinary training) of injuries during the first year. Onset of menarche and a length growth between 6 and 8 cm during the first year were characteristic traits of the four injured girls. Conclusions From our small study, it appears that young athletes attending a specialised secondary sport school experienced many stressors due to a significant increase in training volume, reduction in sleeping time and development of severe and long-lasting injuries. Hence, trainers at sport schools, club trainers and parents need to communicate and support them in order to prevent this.

Assessment of Parasympathetic Activity in Athletes: Comparing Two Different Methods.

INTRODUCTION A variety of methods are used to assess parasympathetic activity in athletes targeting different organs; however, the reliability of or interchangeability between measurement procedures is not clear. OBJECTIVE The purpose of this study is to identify the repeatability of two parasympathetic activity measurement procedures, the HR variability during a 4-s exercise test (4sET), and the contractile properties of the pupil (pupillometry), and to assess their agreement. The secondary objective of this study is to assess their relationship with the bronchodilating effect of inhaled ipratropium bromide (iIB), blocking parasympathetic signals to the lungs. METHODS Forty athletic subjects were enrolled in a cross-sectional study. After 15-min resting in semidarkness, subjects underwent pupillometry (PLR-200™, NeurOptics Inc., CA), followed by 4sET on a cycle ergometer. HR variability was assessed by Polar Electro® HR monitor (RS-800CX/G3; Oy, Kempele, Finland). Both protocols were repeated after 5 min. Statistical analysis was performed according to Bland and Altman and by using Pearsons correlation coefficient and intraclass correlation. Lung function measurements by flow volume curves were performed before and 45 min after iIB. RESULTS The means of differences were 1.21% (limits of agreement, -3.59 to 6.02) for pupil constriction and 0.05 mm (-0.28 to 0.39) for pupil amplitude. The mean of differences for 4sET was 0.005 (-0.31 to 0.32). A very weak intraclass correlation (r = -0.01, P = 0.58) showed no agreement between the methods. No correlation was observed between pupillometry variables or 4sET with the change in lung function after iIB. CONCLUSION Pupillometry showed better repeatability compared with the 4sET. There is poor agreement between parasympathetic activity levels measured in three different target organs of athletic subjects; the heart, the pupil, and the lung. Thus, methods assessing parasympathetic activity in different target organs cannot be used interchangeably.

Exhaled nitric oxide concentration in the period of 60 min after submaximal exercise in the cold.

Fractional expired nitric oxide (FENO) is decreased after exercise. The effect of exercise in the cold upon FENO is unknown.