Exercise Intolerance in Long Covid After 24 Months From Severe Acute Disease: is There Room for Improvement? (preprint)

Introduction: Long COVID is a complex and multisystemic condition, where dyspnea, fatigue, post-exertional malaise, cognitive impairment, decreased functional capacity, and deterioration in quality of life are the most incident clinical features. Few studies have reported cardiopulmonary alterations 24 months after severe COVID-19 infection.  Objective: to evaluate the functional capacity of individuals with persistent symptoms after severe COVID-19 infection compared to control individuals without symptomatic COVID or mild COVID after 24 months.  Methods: This is a case-control study assessing 34 individuals divided into 2 groups (severe COVID-19 with long COVID and a control group consisting of asymptomatic/mild acute COVID-19 with no long COVID) regarding functional capacity by 6-minute walk test (6MWT) associated with gas analysis, spirometry, respiratory muscle strength and quality of life. Results: During the 6MWT, an important lower heart rate (HR) was observed for the COVID group, with greater exertional perception, a significant decrease in the distance covered, and a low value of O2 uptake (V̇O2) and minute ventilation, in addition to very low quality of life scores, especially in aspects of functional capacity and physical limitations.  Conclusion: individuals who have severe COVID-19 and persist with symptoms have low functional capacity, low V̇O2, low HR behavior, and low quality of life. 

Low handgrip strength is associated with worse functional outcomes in long-Covid (preprint)

The diagnosis of long-Covid is troublesome, even when functional limitations are present. Dynapenia is a decrease in muscle strength and power production and may explain in part these limitations. This study aimed to identify the distribution and possible association of dynapenia with functional assessment in patients with long-Covid. A total of 113 inpatients with COVID-19 were evaluated by functional assessment 120 days post-acute severe disease. Body composition, respiratory muscle strength, spirometry, six-minute walk test (6MWT) and hand-grip strength (HGS) were assessed. Dynapenia was defined as HGS < 30kg/f (men), and < 20kg/f (women). Twenty-five (22%) participants were dynapenic, presenting lower muscle mass (p < 0.001), worse forced expiratory volume in the first second (FEV1) (p = 0.0001), lower forced vital capacity (p < 0.001), and inspiratory (p = 0.007) and expiratory (p = 0.002) peek pressures, as well as worse 6MWT performance (p < 0.001). Dynapenia was associated with worse FEV1, MEP, and 6MWT, independent of age (p < 0.001). Patients with dynapenia had higher ICU admission rates (p = 0.01) and need for invasive mechanical ventilation (p = 0.007) during hospitalization. The HGS is a simple, reliable, and low-cost measurement that can be performed in outpatient clinics in low- and middle-income countries. Thus, HGS may be used as a proxy indicator of functional impairment in this population.