Related Experiment Video
Updated: Jul 27, 2025
Author Spotlight: Integrating Alveolar-Capillary Reserve Measurements in Exercise Adaptation and Therapeutic Strategies
Published on: February 2, 2024
Ventilation dynamics using a portable device coupled to the six-minute walk test in people with long-COVID syndrome:
Jéssica Gabriela Messias Oliveira1, Renan Pereira Campos2, Beatriz Luiza Pinheiro Alves Azevedo1
1Department of Pulmonology, Universidade do Estado do Rio de Janeiro (UERJ), Policlínica Piquet Carneiro, Avenida Mal. Rondon, 381, São Francisco Xavier, Rio de Janeiro, 20950-003, Brazil.
Objective:
To investigated the dynamic ventilatory responses and their influence on functional exercise capacity in patients with long-COVID-19 syndrome (LCS).
Results:
Sixteen LCS patients were subjected to resting lung function (spirometry and respiratory oscillometry-RO) and cardiopulmonary performance to exercise (Spiropalm®-equipped six-minute walk test-6MWT and cardiopulmonary exercise test-CPX). At rest, spirometry showed a normal, restrictive and obstructive pattern in 87.5%, 6.25% and 6.25% of participants, respectively. At rest, RO showed increased resonance frequency, increased integrated low-frequency reactance and increased difference between resistance at 4-20 Hz (R4-R20) in 43.7%, 50%, and 31.2% of participants, respectively. The median of six-minute walking distance (DTC6) was 434 (386-478) m, which corresponds to a value of 83% (78-97%) of predicted. Dynamic hyperinflation (DH) and reduced breathing reserve (BR) were detected in 62.5% and 12.5% of participants, respectively. At CPX, the median peak oxygen uptake (VO2peak) was 19 (14-37) ml/kg/min. There was a significant correlation of 6MWD with both R4-R20 (rs=-0.499, P = 0.039) and VO2peak (rs=0.628, P = 0.009). Our results indicate that DH and low BR are contributors to poor exercise performance, which is associated with peripheral airway disease. These are promising results considering that they were achieved with simple, portable ventilatory and metabolic systems.
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