title: Effect of warm-up exercise on exercise-induced bronchoconstriction.
abstract: OBJECTIVE
  Exercise-induced bronchoconstriction (EIB) occurs when vigorous exercise induces bronchoconstriction. Preexercise warm-up routines are frequently used to elicit a refractory period and thus reduce or prevent EIB. This study aimed to conduct a systematic review to evaluate the effectiveness of preexercise routines to attenuate EIB.
  
  
  METHODS
  A comprehensive literature search was performed, with steps taken to avoid publication and selection bias. Preexercise warm-up routines were classified into four groups: interval high intensity, continuous low intensity, continuous high intensity, and variable intensity (i.e., a combination of low intensity up to very high intensity). The EIB response was measured by the percent fall in the forced expiratory volume in 1 s (FEV1) after exercise, and the mean differences (MDs) and 95% confidence intervals (CI) are reported.
  
  
  RESULTS
  Seven randomized studies met the inclusion criteria. The pooled results showed that high intensity (MD = -10.6%, 95% CI = -14.7% to -6.5%) and variable intensity (MD = -10.9%, 95% CI = -14.37% to -7.5%) exercise warm-up attenuated the fall in FEV1. However, continuous low-intensity warm-up (MD = -12.6%, 95% CI = -26.7% to 1.5%) and continuous high-intensity warm-up (MD = -9.8%, 95% CI = -26.0% to 6.4%) failed to result in a statistically significant reduction in bronchoconstriction.
  
  
  CONCLUSIONS
  The most consistent and effective attenuation of EIB was observed with high-intensity interval and variable intensity preexercise warm-ups. These findings indicate that an appropriate warm-up strategy that includes at least some high-intensity exercise may be a short-term nonpharmacological strategy to reducing EIB.
authors.affiliation: Department of Medicine, University of Alberta and Centre for Lung Health (Covenant Health), Edmonton, Alberta, Canada. michael.stickland@ualberta.ca
authors.forename: Michael K
authors.initials: MK
authors.lastname: Stickland
authors.forename: Brian H
authors.initials: BH
authors.lastname: Rowe
authors.forename: Carol H
authors.initials: CH
authors.lastname: Spooner
authors.forename: Ben
authors.initials: B
authors.lastname: Vandermeer
authors.forename: Donna M
authors.initials: DM
authors.lastname: Dryden
mesh_terms: D000318:Adrenergic beta-Agonists / Q000627:therapeutic use; D001250:Asthma, Exercise-Induced / Q000503:physiopathology / Q000517:prevention & control*; D005080:Exercise Test; D005541:Forced Expiratory Volume; D006801:Humans; D005082:Physical Exertion; D016032:Randomized Controlled Trials as Topic
chemical_list: D000318:Adrenergic beta-Agonists