Incremental shuttle walk test: is it able to detect exercise-induced bronchospasm in young adult asthmatics?

Abstract

Objective

To determine the accuracy of incremental Shuttle Walking Test (ISWT) in detecting exercise-induced bronchospasm (EIB) in adults with asthma and to verify whether there is an association of the drop in FEV₁ between ISWT and cardiopulmonary exercise testing with constant-load CPET-CL.

Methods

In this cross-sectional study 32 individuals with asthma performed two ISWTs, an incremental cardiopulmonary exercise test (CPET-I) and a constant-load cardiopulmonary exercise test (CPET-CL) with na interval of 48 h between tests. Spirometric measurements were obtained 5, 10, 15, 20 and 30 min after exercise; an FEV1 decline > 10% was considered EIB.

Results

Fifteen individuals had EIB in both tests [χ2 = 9.41; κ = 0.46 p < 0.002 (95% CI: 0.201-0.708)], with moderate agreement. There was a significant correlation between the greatest variation in the drop in FEV₁ between the ISWT and the CPET-CL (r = 0.48; p < 0.01). There was a significant difference for ventilation maintenance time above 40% of Maximum Voluntary Ventilation between the groups of positive EIB (p = 0.001) and negative EIB (p = 0.001) and for ventilatory demand (positive EIB group) (p = 0.008) between ISWT vs CPET-CL. Moreover, assuming CPET-CL as the criterion test, ISWT presented a sensitivity of 62.5% and specificity was 100%.

Conclusion

ISWT showed moderate accuracy in detecting EIB in adults with asthma and was able to show similar metabolic and ventilatory demand presented in CPET-CL.

Keywords:

• Exercise induced
• asthma exercise-induced
• ISWT
• sensitivity
• specificity

Acknowledgements

The authors would like to thank all the subjects who participated in this study and the financial support (FAPESP process n° 201123771–7) for the development of this project.

Authors contributions

Involvement in the conception, hypotheses delineation, and design of the study: IGL; VAPDL. Data acquisition: IGL, ASGA, FPGR. Data analysis and interpretation: IGL; ABS; VAPDL; JFA. Writing the article: IGL; VAPDL; ABS. Involvement in its revision prior to submission: IGL; ASGA; ABS; VAPDL. Approved the final version: IGL; ASGA; JFA; FPGR; ABS; VAPDL.

Institution where the study was performed

Universidade Federal de São Carlos, in São Carlos, São Paulo, Brazil.

Declaration of interest

The authors declare that there is no conflict of interest.

Additional information

Funding

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) that provided scholarships to fund this Project (processo n° 201123771–7) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES). The authors would like to thank FAPESP for the financial support.