Background: COVID-19 is the most common cause of increased levels of cortisol and interleukin 6 (IL-6). The purpose of this pilot study was to examine the effect of home-based resistance training on the serum levels of IL-6 and cortisol in recovered women with COVID-19.
Materials and Methods: A pilot randomized controlled design was used. Twenty middle-aged women who recovered from COVID-19 were assigned randomly to the intervention and control groups. The height, weight, and body mass index (BMI) of all participants were measured both before and after the intervention period. Blood samples were taken in the morning to determine the serum levels of IL-6 and cortisol. Fitness (estimated VO2 max) was assessed with a 1.6-km walking test. The intervention group followed eight weeks, three days per week, 1 hour per day of thera-band resistance training and body weight training at home. The control group did not participate in any sports program. 
Results: At baseline, there were no significant differences between both groups in the mean IL-6, and cortisol levels (P>0.05). After the intervention, the mean IL-6 and cortisol levels significantly decreased in the intervention group (P<0.05).
Conclusion: Eight weeks of thera-band resistance band training program and bodyweight workout decreases the serum levels of cortisol and IL-6 and improves the immune system of recovered women with COVID-19. Additionally, there seem to be some indications that this training might have a positive influence on immune function. Further research in this area is highly recommended.