Abstract
COVID-19 is a highly contagious virus that uses Angiotensin-converting enzyme 2 (ACE2) as a receptor to enter human cells. The virus leads to an increase in inflammatory cytokines (i.e. IL-6) and an impaired coagulation system, which can cause serious complications during and after the disease. Physical exercise has been shown to improve COVID-19 complications through various mechanisms, such as modulation of the immune and coagulation systems. Therefore, this study investigated the effects of 8 weeks of training on inflammatory, coagulation, and physical factors in patients with COVID-19 during the recovery phase. Twenty-seven male and female volunteers (age 20-45 years) who recently recovered from COVID-19 were assigned to the control (n = 13) or the training group (n = 14). Blood samples, aerobic capacity and muscle endurance were collected 24 h before the start of the interventions and 24 h after the final training session in week 4 and 48 h after the final training session in week 8. IL-6, ACE2, fibrinogen, and D-dimer were measured using ELISA. The training group showed a significant increase in muscle endurance (p = 0.004) and aerobic capacity (p = 0.009) compared to the control group. Serum levels of IL-6 and fibrinogen decreased in the training group but this decrease was not statistically significant (p > 0.05). Despite a slight increase in the quality of life and sleep in the training group, no statistically significant difference was observed between the training and the control group. It appears that physical training has beneficial effects on the coagulation system, inflammatory factors, and sleep quality and can facilitate the recovery of COVID-19 patients.