ASTHMA AND EXERCISE

Predictors of exercise-induced bronchoconstriction in subjects with mild asthma

Background

Physical effort is capable of triggering airway obstruction in asthmatics, the so-called exercise-induced bronchoconstriction in asthma (EIBa). This study was performed in subjects with mild persistent asthma, aiming to find predictors for developing EIBa.

Methods

In 20 subjects with mild asthma, measurements of baseline functional respiratory parameters and airways responsiveness by a methacholine challenge were obtained on the first day. A maximal, symptom-limited incremental cardiopulmonary exercise test (CPExT) was performed the day after, with subsequent, repeated maneuvers of maximal full forced expiration to monitor the FEV₁ change at 1,3,5,7,10 and 15 min after the end of the exercise.

Results

19 subjects completed the two-days protocol. No functional parameters both at rest and during effort were useful to predict EIBa after stopping exercise. In asthmatics with EIBa, mean Inspiratory Capacity (IC) did not increase with increasing ventilatory requirements during CPExT because 6 of them (50%) displayed dynamic pulmonary hyperinflation (DH), as documented by their progressive increase of end-expiratory lung volume. This subgroup, showing earlier post-exercise FEV₁ fall, had significantly lower forced mean expiratory flow between 25% and 75% of forced vital capacity (FEF_25-75%) at rest (p < 0.05) and higher airways responsiveness, expressed as PD₂₀FEV₁ (p < 0.05) as compared with other asthmatics with EIBa.

Conclusions

No functional respiratory parameters seem to predict EIBa in mild asthmatics. However, in those with EIBa, a subgroup developed DH during exercise, and this was associated with a baseline reduced forced expiratory flow rates at lower lung volumes and higher airway hyperresponsiveness, suggesting a prominent small airways impairment.

Childhood asthma and physical activity: a systematic review with meta-analysis and Graphic Appraisal Tool for Epidemiology assessment

BACKGROUND

Childhood asthma is a global problem affecting the respiratory health of children. Physical activity (PA) plays a role in the relationship between asthma and respiratory health. We hypothesized that a low level of PA would be associated with asthma in children and adolescents. The objectives of our study were to (1) summarize the evidence available on associations between PA and asthma prevalence in children and adolescents and (2) assess the role of PA in new-onset or incident asthma among children and adolescents.

METHODS

We searched Medline, the Cochrane Library, and Embase and extracted data from original articles that met the inclusion criteria. Summary odds ratios (ORs) and confidence intervals (CIs) were used to express the results of the meta-analysis (forest plot). We explored heterogeneity using funnel plots and the Graphic Appraisal Tool for Epidemiology (GATE).

RESULTS

We retrieved 1,571 titles and selected 11 articles describing three cohort and eight cross-sectional studies for inclusion. A meta-analysis of the cohort studies revealed a risk of new-onset asthma in children with low PA (OR [95 % CI] 1.32 [0.95; 1.84] [random effects] and 1.35 [1.13; 1.62] [fixed effects]). Three cross-sectional studies identified significant positive associations between childhood asthma or asthma symptoms and low PA.

CONCLUSIONS

Children and adolescents with low PA levels had an increased risk of new-onset asthma, and some had a higher risk of current asthma/or wheezing; however, there was some heterogeneity among the studies. This review reveals a critical need for future longitudinal assessments of low PA, its mechanisms, and its implications for incident asthma in children. The systematic review was prospectively registered at PROSPERO (registration number: CRD42014013761; available at: http://www.crd.york.ac.uk/PROSPERO [accessed: 24 March 2016]).

Incidence of exercise-induced asthma in adolescent athletes under different training and environmental conditions

The aim of this study was to establish if there were differences in the incidence of exercise-induced bronchospasm between athletes in different sports, which take place under different environmental conditions such as open places, closed courses, and swimming pools with similar exercise intensity (football, basketball, water polo) using the free running test. The study included 90 adolescents (3 groups of 30) aged 14-18 years recruited from academies in northern Greece. All the participants were initially subjected to (a) a clinical examination and cardiorespiratory assessment by a physician and (b) free running test of a 6-minute duration and measurement with a microspirometer of the forced expiratory volume in 1 second (FEV₁). Only the participants who had measured a decrease in FEV₁ ≥ 10% were reevaluated with the microspirometer during a training session. The examination of all the participants during the free running test showed that 22 athletes, that is, 9, 8, and 5 of football, basketball, and water polo athletes, respectively, demonstrated an FEV₁ ≥ 10 drop. Reevaluation of the 22 participants during training showed that 5 out 9 (55%) football athletes, 4 out of 8 basketball athletes (50%), and none of the 5 athletes of the water polo team displayed a drop of FEV₁ ≥ 10%. Despite the absence of any significant statistical differences between the 3 groups, the analysis of variances did show a trend of a lower incidence of EIA in the water polo athletes. It was found that a football or basketball game can induce EIA in young athletes but to a lesser degree than the free running test can induce. The water polo can be a safer sport even for participants with a medical history of asthma or allergies.

Lifestyle and the Respiratory Health of Children

This article offers a review of the potential influences of personal lifestyle on respiratory health in children, looking at both healthy individuals and those with respiratory disorders. As with many aspects of health, regular physical activity, an appropriate diet, and avoidance of obesity and cigarette smoke all contribute to optimal development of the healthy child. An active lifestyle is associated with greater static and dynamic lung volumes, greater efficiency of the ventilatory process, and an optimization of breathing patterns. The risk of upper respiratory infections is also reduced in those maintaining a moderate level of physical activity. Maternal smoking during pregnancy, as well as active and passive smoking, all have an adverse influence on lung function in the child, the largest effects being on dynamic lung volumes. The risk of developing asthma seems reduced in children who maintain a normal body mass and are physically active. A program of graded physical activity is of therapeutic value in a number of established respiratory conditions, including asthma, cystic fibrosis, and ventilatory impairment from neuromuscular disorders. Exercise carries a slight risk of fatalities from asthma and anaphylactic reactions. In designing an optimal physical activity program, it is also important to guard against the hazards of deep oronasal breathing, including the precipitation of bronchospasm by the inhalation of cold, dry air and pollens; an increased exposure to atmospheric pollutants (reducing and oxidant smog, fine and ultra-fine particulates, and carbon monoxide); and possible long-term dangers from chlorine derivatives in the atmosphere of indoor swimming pools.

Asthma as a barrier to children's physical activity: implications for body mass index and mental health

OBJECTIVES

The purpose of this work was to identify barriers to physical activity in children with asthma and to compare their customary activity levels, BMI and emotional well-being with that of children with other medical conditions. It was hypothesized that children with asthma would have higher BMI and lower levels of customary activity.

PATIENTS AND METHODS

We studied children aged 7 to 14 years attending hospital outpatient clinics for either asthma (asthma group: n = 56) or for otorhinolaryngology or dermatological conditions (nonasthma group: n = 61). In this cross-sectional survey, children's weight and height were recorded and their BMI classified according to International Obesity Task Force classification of obesity. Child mental health was assessed by the parent-rated Strengths and Difficulties Questionnaire. The child-rated Physical Activity Questionnaire assessed total sedentary and physical activities during the previous 24 hours.

RESULTS

The asthma group had a higher mean BMI (20.78 vs 18.82) and higher rates of obesity (21.4% vs 6.6%). Children with asthma reported fewer physical activities than the nonasthma group (median 4 per day vs 6 per day) but comparable levels of sedentary activities. Asthma was the strongest predictor of lower activity scores, followed by younger age. The asthma group had higher levels of emotional difficulties and, within this group, more active children had better mental health. More parents in the asthma group identified the child's health as a barrier to exercise (60.7% vs 11%). The same was true of children (66.1% vs 11.5%).

CONCLUSIONS

We found that children attending a hospital clinic for asthma were more likely to be obese and were significantly less active than a comparison group with other medical conditions. Asthma was identified as a barrier to exercise by parents and children. Strategies to promote exercise within pediatric asthma care are needed to protect both mental and physical health.

Clinical Role of Rapid-Incremental Tests in the Evaluation of Exercise-Induced Bronchoconstriction

STUDY OBJECTIVE

To determine whether rapid-incremental work rate (IWR) testing would be as useful as standard high-intensity constant work rate (CWR) protocols in eliciting exercise-induced bronchoconstriction (EIB) in susceptible subjects.

DESIGN AND SETTING

A cross-sectional study performed in a clinical laboratory of a tertiary, university-based center.

SUBJECTS AND MEASUREMENTS

Fifty-eight subjects (32 males, age range, 9 to 45 years) with suspected EIB were submitted to CWR testing (American Thoracic Society/European Respiratory Society guidelines) and IWR testing on different days; 21 subjects repeated both tests within 4 weeks. Spirometric measurements were obtained 5, 10, 15, and 20 min after exercise; a FEV1 decline > 10% defined EIB.

RESULTS

Twenty-seven subjects presented with EIB either after CWR or IWR testing; 21 subjects had EIB in response to both protocols (kappa = 0.78, excellent agreement; p < 0.001). Of the six subjects in whom discordant results were found, two had EIB only after IWR. Assuming CWR as the criterion test, IWR combined high positive and negative predictive values for EIB detection (91.3% and 88.6%, respectively). Tests reproducibility in eliciting EIB were similar (kappa = 0.80 and 0.72 for CWR and IWR, respectively; p < 0.001). Total and intense (minute ventilation > 40% of maximum voluntary ventilation) ventilatory stresses did not differ between EIB-positive and EIB-negative subjects, independent of the test format. There were no significant between-test differences on FEV(1) decline in EIB-positive subjects (25.7 +/- 10.8% vs 23.7 +/- 10.0%, respectively; p > 0.05). Therefore, no correlation was found between exercise ventilatory response and the magnitude of EIB after either test (p > 0.05).

CONCLUSIONS

Rapid-incremental protocols (8 to 12 min in duration) can be as useful as high-intensity CWR tests in diagnosing EIB in susceptible subjects. Postexercise spirometry should be performed after incremental cardiopulmonary exercise testing when EIB is clinically suspected.

Airways hyperresponsiveness in high school athletes

Adult athletes have a higher prevalence (11%-50%) of exercise-induced bronchoconstriction (EIB) and airways hyperresponsiveness (AHR) than the population at large (7%-11%): reports describing EIB/AHR in adolescent athletes are scant.

HYPOTHESES

1) a minimum AHR prevalence of 20% would be revealed in a group of high school athletes; 2) demographic data would predict AHR; 3) AHR-positive athletes would preferentially choose low ventilation sports. Eucapnic voluntary hyperpnea (EVH) was used to test for AHR in 23% of all athletes (79 of 343) of a midwestern high school. The AHR was defined by at least a 10%, 20%, or 25% decline in FEV1, FEF25-75, or PEFR at 1, 5, 10, or 15-min post-EVH, respectively.

RESULTS

30 of 79 (38%) tested positive for AHR; demographic data tended to predict AHR, as correlations between the total number of years exercised with the greatest decline in FEV1 and the total number of days exercised with the greatest decline in FEV1 following the EVH challenge tended to be significant (r = 0.354; p = 0.055 and r=0.314; p = 0.091, respectively); and 69% of AHR-positive students played only low ventilation sports.

CONCLUSION

AHR prevalence was 38% in athletes of a midwestern high school; demographic data tended to predict AHR; those with AHR preferentially play low ventilation sports.

Physical activity in urban school-aged children with asthma

OBJECTIVES

To compare the physical activity levels of children with and without asthma and evaluate predictors of activity level in children with asthma.

METHODS

Parents of 137 children with asthma and 106 controls 6 to 12 years old who attended an urban primary care pediatric clinic were interviewed by telephone. A structured survey evaluated 1 day's total activity and the number of days active in a typical week; asthma characteristics and treatment; physician advice; opportunities for physical activity; and caregiver beliefs about physical activity. The activity levels of children with and without asthma were compared. Predictors of activity level of children with asthma were evaluated.

RESULTS

Children with asthma were less active than their peers. The mean amount of daily activity differed by group: 116 (asthma) vs 146 (nonasthma) minutes; 21% (asthma) vs 9% (nonasthma) were active <30 minutes/day; and 23% (asthma) vs 11% (nonasthma) were active <3 days/week. Among children with asthma, disease severity and parental beliefs regarding exercise and asthma predicted activity level. Children with moderate or severe persistent asthma were more likely to be active <30 minutes/day (odds ratio: 3.0; confidence interval: 1.2-7.5), and children whose parents believed exercise could improve asthma were more likely to be highly active > or = 120 minutes/day (odds ratio: 2.5; confidence interval: 1.2-5.4).

CONCLUSIONS

Disease severity and parental health beliefs contribute to the lower activity level of children with asthma. Pediatricians should evaluate exercise level as an indicator of disease control and address exercise and its benefits with patients and caregivers to help achieve the goal of normal physical activity in children with asthma.

Pulmonary disorders and exercise

The respiratory system rarely limits exercise in the normal subject. In patients with chronic pulmonary processes or in the elite athlete, however, the respiratory system may indeed be the limiting factor. Common respiratory disorders include chest pain syndromes, cough, exercise-induced asthma, and vocal cord dysfunction. Chronic lung diseases such as asthma, COPD, and interstitial lung disease impact exercise capacity and endurance. Exercise testing can be useful to distinguish acute and chronic pulmonary causes of dyspnea during exercise, as well as to differentiate between cardiac and pulmonary causes.

Prevalence and mechanisms of development of asthma and airway hyperresponsiveness in athletes

A high prevalence of asthma and airway hyperresponsiveness (AHR) has been reported in the athlete population. Factors potentially predisposing athletes to these conditions have not been clearly identified. Although moderate exercise has been shown to be beneficial in patients with asthma, repeated high-intensity exercise could possibly contribute to the development of asthma and AHR. This report provides an overview of the prevalence and possible mechanisms of development of asthma and AHR in the athlete population. The prevalence of asthma and AHR are higher in athletes than in the general population, particularly in swimmers and athletes performing sports in cold air environments. Possible mechanisms involved in the development of asthma in athletes are still uncertain; however, the content and physical characteristics of the inhaled air seem to be important factors, while immune and neurohumoral influences could play a modulatory role. This report stresses the need for further studies to better define the aetiologic factors and mechanisms involved in the development of asthma and AHR in athletes, and proposes relevant preventive and therapeutic measures.

Clinical exercise testing

Clinical exercise testing is increasingly being utilized in clinical practice because of the valuable, often unique information that it provides in patient diagnosis and management. This is also due to a growing awareness that resting cardiopulmonary measurements provide an unreliable estimate of functional capacity. A continuum of exercise testing modalities for functional evaluation from "low tech" to "high tech" will be discussed. These include the six minute walk test, shuttle walk test, exercise induced bronchoconstriction test, cardiac stress test, and cardiopulmonary exercise testing. The main focus of this article will be cardiopulmonary exercise testing including indications, important measurements, salient methodological considerations, and interpretation.

Asthma and maternal body mass index are related to pediatric body mass index and obesity: results from the Third National Health and Nutrition Examination Survey

OBJECTIVE

Clinical research has shown an increased prevalence of obesity in children with asthma. This study was designed to assess the relationship between asthma and pediatric body mass index (BMI) in a national database and to examine factors that may modify this relationship.

DESIGN

The cross-sectional relationship between asthma and pediatric BMI and obesity (BMI > or = 85th percentile) was studied. Variables that may influence the relationship between asthma and pediatric BMI, such as race/ethnicity and television watching were included in the model for the total sample. A smaller sample of 3,009 white and African American youth were studied in regression models including maternal BMI.

STUDY POPULATION

A nationally representative cross-sectional sample of 5154 children and adolescents of 6 to 16 years of age from the Third National Health And Nutrition Examination Survey.

RESULTS

In the full sample, asthma and television watching were related to BMI, accounting for 3% of the variance in BMI. When maternal BMI was included in the non-Hispanic sample, television watching, maternal BMI, and the interaction of maternal BMI and asthma were related to youth BMI, accounting for 15% of the variance. The standardized BMI z-score for those youth without asthma and no maternal obesity was 0.06, which increased to 0.33 if the youth had asthma, to 0.70 if the youth did not have asthma but the mother was obese, and to 1.71 if the youth had asthma and the mother was obese. Asthma, television watching, and maternal BMI were independent predictors of youth obesity.

CONCLUSIONS

BMI and prevalence of obesity is higher in youth with asthma. Pediatric BMI, but not obesity, is also related to the interaction of asthma and maternal BMI in white and African American youth. Comorbidity of asthma and obesity may complicate treatment of either condition, and prevention of obesity should be encouraged for asthmatic children.

Oral montelukast compared with inhaled salmeterol to prevent exercise-induced bronchoconstriction. A randomized, double-blind trial. Exercise Study Group

BACKGROUND

Montelukast, an oral, once-daily leukotriene receptor antagonist, provides protection against exercise-induced bronchoconstriction.

OBJECTIVE

To evaluate the effect of 8 weeks of therapy with salmeterol aerosol or montelukast on exercise-induced bronchoconstriction in adults with asthma.

DESIGN

8-week multicenter, randomized, double-blind study.

SETTING

17 asthma treatment centers in the United States.

PATIENTS

191 adults with asthma who had documented exercise-induced bronchoconstriction.

INTERVENTION

Qualified patients were randomly assigned to double-blind treatment with montelukast (10 mg once in the evening) or salmeterol (50 microg [2 puffs] twice daily).

MEASUREMENTS

Changes in pre-exercise and postexercise challenge values; percentage inhibition in the maximal percentage decrease in FEV1; the area above the FEV1-time curve; and time to recovery of FEV1 at days 1 to 3, week 4, and week 8 of treatment.

RESULTS

By day 3, similar and statistically significant reductions in maximal percentage decrease in FEV1 were seen with both therapies. Sustained improvement occurred in the montelukast group at weeks 4 and 8; at these time points, the bronchoprotective effect of salmeterol decreased significantly. At week 8, the percentage inhibition in the maximal percentage decrease in FEV1 was 57.2% in the montelukast group and 33.0% in the salmeterol group (P = 0.002). By week 8, 67% of patients receiving montelukast and 46% of patients receiving salmeterol had a maximal percentage decrease in FEV1 of less than 20%.

CONCLUSIONS

The bronchoprotective effect of montelukast was maintained throughout 8 weeks of study. In contrast, significant loss of bronchoprotection at weeks 4 and 8 was seen with salmeterol. Long-term administration of montelukast provided consistent inhibition of exercise-induced bronchoconstriction at the end of the 8-week dosing interval without tolerance.

Exercise for asthma patients: little risk, big rewards

The standard exercise recommendation -20 to 30 minutes at 60% to 85% of maximum heart rate four or five times a week- should be part of asthma management. Not only will patients benefit in a general way, but improved fitness is likely to reduce airway reactivity and medication use. The capacity to exercise, however, requires good general control of asthma, including use of inhaled corticosteroids and avoidance of triggers. In addition, patients must be taught to prevent exercise-induced bronchoconstriction by using inhaled medications and strategies like avoiding cold-weather exercise.

Pharmacologic treatment of exercise-induced asthma

Exercise-induced asthma (EIA) is a complex disorder affecting a sizeable minority of athletes. Proper pharmacologic management allows most every athlete at any level to participate with EIA. This article briefly addresses the pathophysiology, diagnosis, and basic treatment principles, including nonpharmacologic management for EIA. Most of the article details the current treatment strategies and provides information on experimental treatments being investigated. In addition, ergogenic concerns and problems in treating elite athletes are discussed.

Role of exercise in the evaluation and management of pulmonary disease in children and youth

Asthma is the most common chronic pulmonary disorder affecting children in the U.S. Cystic fibrosis is the most common life-shortening inherited disease affecting white populations. With both disorders, children may have impaired exercise tolerance and abnormal cardiopulmonary responses to exercise. Exercise testing can aid in the diagnosis of exercise-induced asthma, and in determining prognosis in cystic fibrosis. Children with asthma and cystic fibrosis have been shown to benefit from exercise training, mainly through improved aerobic fitness and cardiopulmonary efficiency. In summary, exercise plays a valuable role in the evaluation and management of children with asthma and cystic fibrosis.

The incidence of exercise-induced bronchospasm in competitive figure skaters

Pediatric commitment to competitive sports is on the rise. Previous reports of the incidence of exercise-induced bronchospasm (EIB) have investigated high school, college, and Olympic athletes in traditional sports. The purpose of this study was to investigate the incidence of EIB in competitive figure skating, a high-intensity, cold-weather sport performed by young athletes. To investigate the incidence of EIB in skaters, 100 competitive skaters from five Mid-Atlantic rinks completed rinkside pulmonary function tests. Results showed an overall incidence of 30%, signaling the need for education and screening for EIB in youth participating in physically demanding, cold-weather sports.

Prolonged recovery from exercise-induced asthma with increasing age in childhood

It has been suggested that children with asthma recover more quickly from exercise-induced bronchoconstriction than adults. On the basis of clinical observation we hypothesized that recovery rate from exercise-induced asthma (EIA) in childhood also decreases with age. In 14 children (aged 7-12 years) with a history of EIA, we measured spontaneous recovery from bronchoconstriction induced by two different stimuli: exercise and histamine. The children visited the laboratory three times. After a screening exercise test on the first visit, standardized bronchoprovocation tests with either exercise or histamine were performed on the following two visits in random order. The degree of bronchoconstriction induced by histamine was matched for that observed after exercise. During recovery, forced expiratory volume in 1 second (FEV1) was measured repeatedly up to 2 hours postchallenge. The recovery rate (% increase in FEV1/min) was calculated from the linear slope of the time-response curve. Differences in recovery rate between the two stimuli were analyzed by paired t-test, and age-related differences were analyzed using multiple regression analysis. For the group as a whole, recovery rate was not different between the two stimuli (mean +/- SD: 1.22 +/- 0.91 for exercise, and 1.46 +/- 0.65, for histamine, P = 0.31). However, the recovery rate for exercise-induced bronchoconstriction decreased significantly with age (r = -0.74, P = 0.003), in contrast to the recovery rate for histamine (r = -0.15, P = 0.60). Consequently, in the oldest age group (11-12 years, n = 5) recovery rate from exercise challenge was significantly slower than in the younger age group (7-10 years, n = 9), i.e., 0.54 +/- 0.17 and 1.60 +/- 0.93, respectively, P = 0.009, and slower than the recovery rate from histamine challenge: 0.54 +/- 0.17 and 1.33 +/- 0.54, respectively, P = 0.03. In the younger age group the recovery rates from exercise and histamine were not different (1.60 +/- 0.93 and 1.54 +/- 0.73, respectively, P = 0.83). We conclude that recovery from EIA in childhood decreases with increasing age. These data suggest that the mechanism of exercise-induced asthma in childhood changes with age. This might be due to changes in mediator production or response to mediator release.