This article requires a subscription to view the full text. If you have a subscription you may use the login form below to view the article. Access to this article can also be purchased.
Abstract
BACKGROUND: Single-step tests have been proposed as simple and inexpensive challenges to diagnose exercise-induced bronchoconstriction (EIB) in the pediatric population. Work performed and the resulting ventilation, however, might be substantially lower in stepping than running. This might decrease the diagnostic yield of step-based challenges.
METHODS: In a cross-sectional study, 53 children with asthma with exercise-related symptoms (34 boys, age 6–18 y) underwent an incremental stepping test, a 6-min constant stepping test, and a treadmill running test on different days.
RESULTS: Constant and incremental stepping tests presented with lower metabolic demands (V̇O2 1.42 ± 0.48 and 1.34 ± 0.55 L/min, respectively), ventilatory demands (V̇O2 45 ± 14 and 43 ± 16 L/min, respectively), and cardiovascular demands (160 ± 20 and 161 ± 19 beats/min, respectively) than the treadmill running test (1.65 ± 0.60 L/min, 54 ± 17 L/min, and 172 ± 7 beats/min, respectively) (P < .05). Between-test agreement in diagnosing EIB was poor (kappa 0.217–0.361). Although EIB prevalence was higher after the treadmill running test (60%) compared to constant (53%) and incremental (47%) stepping tests, 7 subjects developed EIB only in stepping. Clinical and resting functional characteristics did not differ in discordant subjects (ie, EIB negative in a given test but positive in another) versus concordant subjects (ie, EIB negative or positive in both tests). EIB was not related to individual test ability in eliciting high to very-high ventilation (≥ 40% or ≥ 60% maximum voluntary ventilation, respectively). Moreover, a negative stepping test but a positive treadmill test (and vice versa) was not associated with greater ventilatory demands.
CONCLUSIONS: Lower prevalence of EIB in stepping compared to treadmill running is not related to less ventilation demand in the former modality. Although stepping might be useful as a screening EIB test due its portability and low cost, a negative test should be confirmed with a running-based test in symptomatic children.
Footnotes
- Correspondence: Simone Dal Corso PT PhD, Universidade Nove de Julho, Rua Vergueiro no. 235/249, 2o subsolo, Liberdade, São Paulo, Brazil 01504-050. E-mail: si.dal.corso{at}gmail.com.
Ms Selman presented a version of this manuscript at the 17th Congresso Paulista de Pneumologia e Tisiologia, held November 15-18, 2017, in São Paulo, Brazil.
Ms Selman has disclosed a relationship with the São Paulo Research Foundation. The other authors have disclosed no conflicts of interest.
Supplementary material related to this paper is available at http://www.rcjournal.com.
- Copyright © 2019 by Daedalus Enterprises
Pay Per Article - You may access this article (from the computer you are currently using) for 1 day for US$15.00
Regain Access - You can regain access to a recent Pay per Article purchase if your access period has not yet expired.
Log in using your username and password
