title: Prevalence and Characteristics of Exercise-Induced Bronchoconstriction in High School and College Athletes at 2,240 m Altitude.
abstract: BACKGROUND
  Athletes practicing strenuous physical activities may develop exercise-induced bronchoconstriction (EIB). We aimed to determine the prevalence and features of this condition in Mexico City (altitude, 2,240 m).
  
  
  METHODS
  In the present study, 208 high school and college athletes performed a standardized EIB test on a treadmill.
  
  
  RESULTS
  Responses to exercise had large between-subject variability in all physiological parameters (forced expiratory volume in one second [FEV1], heart rate, blood oxygen saturation level [SpO2], blood pressure), with nearly similar proportions of subjects in whom FEV1 increased or decreased. According to the recommended cut-off value of 10% FEV1 decrease, only 15 (7.2%) athletes had a positive EIB test. Weight lifters were more prone to develop EIB (three out of seven athletes; p = 0.01). Subjects with a positive EIB test already had a lower baseline forced expiratory volume in one second/forced vital capacity (FEV1/FVC) ratio (96.4 vs. 103.2% of predicted, respectively; p = 0.047), and developed more respiratory symptoms after exercise than subjects with a negative test. There were no differences with respect to age, gender, body mass index, history of asthma or atopic diseases, smoking habit, and exposure to potential indoor allergens.
  
  
  CONCLUSIONS
  The relatively low prevalence of EIB in athletes from Mexico City raises the possibility that high altitude constitutes a protective factor for EIB. In contrast, weight lifters were especially prone to develop EIB, which suggests that repetitive Valsalva maneuvers could be a novel risk factor for EIB. There was a large between-subject variability of all physiological responses to exercise.
authors.affiliation: Department of Allergy and Clinical Immunology, Hospital de Especialidades, Centro Médico Nacional La Raza, Instituto Mexicano del Seguro Social, Mexico City, Mexico.
authors.forename: Martín
authors.initials: M
authors.lastname: Becerril-Ángeles
authors.affiliation: Medical Research Unit in Respiratory Diseases, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico.|Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Mexico City, Mexico.
authors.forename: Mario H
authors.initials: MH
authors.lastname: Vargas
authors.affiliation: Faculty of Medicine, Universidad Nacional Autónoma de México, Mexico City, Mexico.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Hernández-Pérez
authors.affiliation: Faculty of Medicine, Universidad Nacional Autónoma de México, Mexico City, Mexico.
authors.forename: Nancy Judith
authors.initials: NJ
authors.lastname: Rivera-Istepan
authors.affiliation: Fellowship Program from the Consejo Nacional de Ciencia y Tecnología, Mexico City, Mexico.
authors.forename: Rebeca Ivonne
authors.initials: RI
authors.lastname: Pérez-Hidalgo
authors.affiliation: Faculty of Medicine, Universidad Nacional Autónoma de México, Mexico City, Mexico.
authors.forename: Ana Gabriela
authors.initials: AG
authors.lastname: Ortega-González
authors.affiliation: Sports and Recreational Activities General Directorate, Universidad Nacional Autónoma de México, Mexico City, Mexico.
authors.forename: Severino
authors.initials: S
authors.lastname: Rubio-Domínguez
authors.affiliation: Sports and Recreational Activities General Directorate, Universidad Nacional Autónoma de México, Mexico City, Mexico.
authors.forename: María Cristina
authors.initials: MC
authors.lastname: Rodríguez-Gutiérrez
authors.affiliation: Sports and Recreational Activities General Directorate, Universidad Nacional Autónoma de México, Mexico City, Mexico.
authors.forename: Radamés
authors.initials: R
authors.lastname: Gaxiola-Cortés
authors.affiliation: Sports and Recreational Activities General Directorate, Universidad Nacional Autónoma de México, Mexico City, Mexico.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Dosal-Ulloa
authors.affiliation: Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Mexico City, Mexico.
authors.forename: Laura Graciela
authors.initials: LG
authors.lastname: Gochicoa-Rangel
mesh_terms: D000293:Adolescent; D000328:Adult; D000531:Altitude; D001250:Asthma, Exercise-Induced / Q000453:epidemiology*; D056352:Athletes; D016084:Bronchoconstriction / Q000502:physiology*; D002648:Child; D005080:Exercise Test; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008800:Mexico; D015995:Prevalence; D012574:Schools; D014495:Universities; D014797:Vital Capacity; D055815:Young Adult