Long COVID represents a significant challenge in understanding the prolonged impact of the disease. Despite its increasing recognition, detailed insights into the long-term cardiopulmonary consequences remain sparse. This study aimed 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 17 months. This is a case-control study assessing 34 individuals divided into two groups regarding functional capacity by distance in a 6-min walk test (D6MWT) associated with gas analysis, spirometry, respiratory muscle strength, and quality of life. During the 6 MWT, an important lower heart rate (HR) was observed for the COVID group (106 ± 10 bpm, difference mean: 21.3;
p < 0.001), with greater exertional perception (Borg dyspnea: 4.5 [2.0–9.0],
p < 0.001 and Borg fatigue: 4.0 [2.0–7.0],
p = 0.01), a significant decrease in the distance covered (416 ± 94 m, difference mean: 107;
p = 0.002), and a low value of O
2 uptake (
O2) (11 ± 5.0 mL/(kg min), difference mean: 8.3;
p = 0.005) and minute ventilation (22 ± 8 L/min, difference mean: 18.6;
p = 0.002), in addition to very low quality of life scores. Regression analysis showed a significant association between D6MWT and Borg fatigue and Borg dyspnea at rest (
p = 0.003;
p = 0.009).
O2 and HR were also significantly associated with the outcomes of the D6MWT (
p = 0.04 and
p = 0.004, respectively). In conclusion, individuals who have severe COVID-19 and persist with symptoms have low functional capacity, low
O2, low HR behavior, and low quality of life.
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