Background and aim: Pulmonary involvement and fibrosis are prevalent in patients with post COVID-19. Dyspnea, fatigue, pulmonary function abnormalities occur. Abnormalities in skeletal muscles may impair exercise capacity and physical activity levels. However, studies investigating exercise capacity, pulmonary function, physical activity, and fatigue in patients with post-COVID-19 are limited. To compare aforementioned outcomes in patients with post-COVID-19 and controls.

Methods: Patients with pulmonary involvement post-COVID-19 (n=44, DLCO 75.49±2.88%) and healthy controls (n=43) were compared. Exercise capacity (cardiopulmonary exercise test), pulmonary function (spirometry), physical activity (metabolic holter) and fatigue (Fatigue Severity Scale (FSS)) were evaluated.

Results: Patients’ MET, VO2(%), VCO2, VE(%), HRmax(%), O2/HR(%), ATpredVO2(%), SpO2 at max exercise were decreased; HRR, VEO2, VECO2, BR, decrease in SpO2 and dyspnea were higher (p<0.05) and RER, BF and fatigue were similar in groups (p>0.05). Total and active energy expenditure, physical activity duration, number of steps, and average metabolic equivalents (METs/day), lying down duration, pulmonary function test parameters were statistically significantly decreased, FSS scores were higher in patients compared with controls (p<0.05).

Conclusions: Patients with pulmonary involvement post-COVID-19 have significantly deteriorated maximal exercise capacity, physical activity levels and higher fatigue perception. Objective techniques be used to detect the exercise intolerance and physical inactivity to decide whether to start pulmonary rehabilitation and physical activity counseling.