Determinants of exercise capacity in children and adolescents with severe therapy-resistant asthma

Abstract

Objective

To evaluate the exercise capacity of children and adolescents with severe therapy resistant asthma (STRA) aiming to identify its main determinants.

Methods

Cross-sectional study including individuals aged 6–18 years with a diagnosis of STRA. Clinical (age and gender), anthropometric (weight, height and body mass index) and disease control data were collected. Lung function (spirometry), cardiopulmonary exercise testing (CPET) and exercise-induced bronchoconstriction (EIB) test were performed.

Results

Twenty-four patients aged 11.5 ± 2.6 years were included. The mean forced expiratory volume in one second (FEV₁) was 91.3 ± 9.2%. EIB occurred in 54.2% of patients. In CPET, the peak oxygen uptake (VO_2peak) was 34.1 ± 7.8 mL kg⁻¹ min⁻¹. A significant correlation between ventilatory reserve and FEV₁ (r = 0.57; p = 0.003) was found. Similarly, there was a significant correlation between CPET and percent of FEV₁ fall in the EIB test for both V_E/VO₂ (r = 0.47; p = 0.02) and V_E/VCO₂ (r = 0.46; p = 0.02). Patients with FEV₁<80% had lower ventilatory reserve (p = 0.009). In addition, resting heart rate correlated with VO_2peak (r=-0.40; p = 0.04), V_E/VO₂ (r = 0.46; p = 0.02) and V_E/VCO₂ (r = 0.48; p = 0.01).

Conclusions

Exercise capacity is impaired in approximately 30% of children and adolescents with STRA. The results indicate that different aspects of aerobic fitness are influenced by distinct determinants, including lung function and EIB.

KEYWORDS:

• Aerobic fitness
• exercise-induced bronchoconstriction
• oxygen consumption
• lung function
• cardiopulmonary exercise testing

Disclosure statement

The authors report no conflict of interest. The authors alone are responsible for the content and writing of this article.

Additional information

Funding

The researchers would like to thank Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) – finance code 001 – and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for financial support.