RESUMEN
BACKGROUND: To investigate the effects of moderate aerobic exercise on the hemoglobin, hematocrit, and red blood cell (RBC) mass of women with rheumatoid arthritis (RA). MATERIALS AND METHODS: This randomized clinical trial was conducted at the Specialized Clinic of Physical Medicine and Rehabilitation, Al-Zahra Hospital of Isfahan, during a 4-month period in 2014. We included patients with RA who did not have any malignancy and hematologic disorder. Two groups - one group receiving aerobic therapy along with medical therapy (N = 16) and the other group receiving medical therapy alone (N = 17) both for a period of 8 weeks. The levels of RBC mass, Hb, and HCT were measured before and after the intervention. The changes in these parameters were compared between the two study groups. RESULTS: There was no significant difference between the two study groups regarding the baseline characteristics. The aerobic exercise resulted in increased RBC mass (P < 0.001), Hb (P < 0.001), and HCT (P < 0.001). However, those who received medical therapy alone did not experience any significant changes in these parameters. We found that the RBC mass (P = 0.581), Hb (P = 0.882), and HCT (P = 0.471) were comparable between the two study groups after 8 weeks of intervention. CONCLUSION: Although the aerobic exercise results in increased Hb, HCT, and RBC mass in patients with RA, the increase was not significant when compared to that in controls. Thus, the increase in the HB, HCT, and RBC could not be attributable to aerobic exercise.