Avaliação da capacidade de exercício e das variáveis cardiorrespiratórias no teste do degrau de seis minutos por meio de camiseta inteligente, em indivíduos após 24 meses da alta hospitalar por COVID-19

Abstract

COVID-19 may lead to persistent effects on exercise capacity and cardiorespiratory responses, particularly in individuals who required hospitalization. Although reduced exercise capacity following the disease has been widely described, gaps remain regarding its long-term progression and, especially, the behavior of cardiorespiratory responses during exercise. Field-based physical tests allow the quantification of performance and exercise tolerance; however, performance analysis alone does not fully characterize the physiological demands imposed by exercise. In this context, the incorporation of wearable technology into the Six-Minute Step Test (6MST) and the 30-Second Sit-to-Stand Test (30CST) makes it possible to associate performance with continuous monitoring of cardiorespiratory responses during exertion. Therefore, this doctoral thesis investigated exercise capacity and cardiorespiratory responses during field-based physical tests in individuals previously hospitalized for COVID-19 through two complementary studies. The first study longitudinally analyzed changes in exercise capacity and cardiorespiratory responses at 30 days and 24 months after hospital discharge, using field-based physical tests combined with continuous physiological monitoring through a smart shirt. After 24 months, exercise capacity improved; however, alterations in cardiovascular and ventilatory responses during exertion persisted. The second study compared individuals previously hospitalized for COVID-19, assessed approximately two years after hospitalization, with individuals without a history of the disease, using the 6MST and 30CST and analyzing performance in relation to Brazilian predictive equations. The post-COVID-19 group exhibited lower exercise capacity in both tests, with some individuals achieving less than 80% of the predicted values on the 6MST. In addition, greater cardiovascular demand during exercise, slower cardiorespiratory recovery, and higher perceived exertion were observed in the post-COVID-19 group. Taken together, the results demonstrate that cardiorespiratory alterations during exercise may persist in the long term after hospitalization for COVID-19 and that recovery of exercise capacity does not necessarily correspond to the normalization of physiological responses to exertion. Thus, this thesis highlights the importance of assessing not only the performance achieved during field-based physical tests but also the cardiorespiratory responses exhibited throughout their execution. Combining these tests with continuous monitoring using wearable technology adds a physiological dimension to the assessment of exercise capacity and may provide complementary information to support the follow-up and development of rehabilitation strategies for individuals previously hospitalized for COVID-19.