Time Since Infection Impacts Predicted Maximal Vo2 In Covid-19 Survivors

COVID-19 survivors can experience symptoms lasting years, but little is known about the persistent effects on exercise capacity. PURPOSE: To determine if time since infection, symptom severity, and pre-existing comorbidities affect exercise capacity in COVID-19 survivors. METHODS: 94 COVID survivors (63 females) were tested 2-43 mo (9.6 ± 7.2 months since infection, MSI) after infection. Participants self-reported the presence of pre-existing comorbidities associated with the following systems that may impact exercise capacity: neuromuscular (NM; n = 9), cardiovascular (C; n = 26), and respiratory (R; n = 14). The total number of acute symptoms (TAS) and lingering symptoms (TLS) were also self-reported. Physical activity prior to infection (PPA) and at the time of testing (CPA) were self-reported via the International Physical Activity Questionnaire. Participants performed a YMCA submaximal cycling test to predict maximal oxygen consumption (VO2). Point-biserial correlations were run to assess the relationships between sex, NM, C, R, and VO2. Spearman’s correlations were run to assess the relationships between height, weight, body fat percentage (BFP), MSI, TAS, TLS, PPA, CPA and VO2. A multiple regression was run to predict VO2 from all aforementioned variables. RESULTS: Significant correlations between the following variables and VO2 were found: age (rs = -0.46, p < 0.001), sex (rpb = 0.21, p = 0.04), height (rs = 0.28, p = 0.007), weight (rs = -0.36, p < 0.001), BFP (rs = -0.65, p < 0.001), TLS (rs = -0.34, p < 0.001), CPA (rs = 0.24, p = 0.02), and R (rpb = -0.35, p < 0.001). The multiple regression to predict VO2 was significant, F(14, 79) = 6.41, p < 0.001, adj. R2 = 0.45 when all variables were added. Age, BFP, R, and MSI each added significantly to the prediction, p < 0.05. Older age, BFP, and the presence of R decreased VO2, while increasing time since infection increased VO2. CONCLUSION: Respiratory comorbidities (e.g. asthma) in COVID-19 survivors, and known comorbidities such as older age and body fat, predicted a lower VO2. However, as more time passed between acute COVID-19 infection, predicted VO2 increased. These findings may be useful in tailoring exercise prescriptions for COVID-19 survivors suffering from lingering symptoms.