Effect of acute aerobic exercise in different times of day on iron status and hematological factors in professional football players

Background and aims: Exercise time is one of the main challenges of athletes. The purpose of this study was to investigate the effect of acuteaerobic exercise at different times of the day on iron status and hematological factors in professional football players.Methods: In this quasi-experimental study, ۴۰ professional football players were randomly divided into morning exercise, evening exercise,morning control, and evening control groups. The experimental groups performed Bruce’s test in the morning and evening. To measureiron, ferritin, red blood cell (RBC), and hemoglobin (Hb), the blood samples were taken before, immediately after, as well as ۲۴ and ۷۲hours after the Bruce test. Repeated-measure ANOVA and two-way ANOVA (group*time) were used to analyze the obtained data.Results: The results showed a significant increase immediately after an acute aerobic exercise while demonstrating a significant decreasein RBC and Hb in morning and evening exercise groups ۲۴ and ۷۲ hours after the exercise compared to the control groups. In addition, asignificant reduction immediately after the acute aerobic exercise, whereas a significant increase ۲۴ and ۷۲ hours after the exercise, wasobserved in the serum levels of iron and ferritin in the morning and evening exercise groups compared to the control groups. As regardsthe serum levels of iron, an immediate significant decrease, along with a significant increase ۲۴ hours after the acute aerobic exercise wasfound between the morning and evening exercise groups (P ≤ ۰.۰۵).Conclusion: It seems that performing acute endurance training in the evening is safe in terms of reducing the serum levels of iron anddeveloping the “exercise-induced anemia”. Finally, at least ۲۴ hours is required for the recovery of hematological parameters after acuteendurance training.

Keywords:

Acute aerobic activity , Circadian rhythm , Iron status , Hematology factors , Professional football player