Intermittent Hypoxia Exposure Can Prevent Reductions in Hemoglobin Concentration After Intense Exercise Training in Rats

HEMOGLOBIN ANALYSIS AFTER OVERLOAD TRAINING IN ATHLETES

ABSTRACT Introduction: The cardiovascular system provides athletes with the proper conditions for blood circulation, ensuring the stability and normal metabolism of the body's internal environment during exercise. Objective: Investigate the effect of overload training on the hemoglobin of male taekwondo athletes. Methods: Twenty-one male taekwondo athletes (level 2 or higher) were selected and trained for four weeks, five days per week, with an initial load intensity of 60% of the maximum heart rate and a weekly intensity increase of 10%. Before training and on every weekend during training, hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), reticulocyte count (Ret) were checked, RBC volume distribution width (RDW), hemoglobin content distribution width (HDW), mean reticulocyte volume (MCVr), mean reticulocyte hemoglobin concentration (CHCMr), serum iron (Fe) and ferritin (Fer). Results: After four weeks of increasing load training, athletes showed a progressive and significant decrease in Hb (P<0.01), manifested as exercise-induced hypohemoglobin, and MCV, MCH, MCHC, CHCMr, HDW, and serum ferritin were significantly or extremely decreased(P<0.) 05, P<0.01); RDW increased significantly (P<0.05); Changes in Ret and serum iron showed no statistical significance (P>0.05). Correlation analysis found that hemoglobin concentration had the highest correlation with MCHC and CHCMr. Conclusion: Four-week incremental load training can induce exercise-induced hypohemoglobin in male taekwondo athletes, its changes being most correlated with MCHC and CHCMr, but without significant correlation with serum Fe, RDW, HDW, and MCV. Level of Evidence: Therapeutic Studies -Investigation of Outcomes.

Intermittent Hypoxia Exposure Helps to Restore the Reduced Hemoglobin Concentration During Intense Exercise Training in Trained Swimmers

In prolonged intense exercise training, the training load of athletes may be reduced once their hemoglobin concentrations ([Hb]s) are decreased dramatically. We previously reported that intermittent hypoxia exposure (IHE) could be used to alleviate the decrease of [Hb] and help to maintain the training load in rats. To further explore the feasibility of applying IHE intervention to athletes during prolonged intense exercise training, 6 trained swimmers were recruited to conduct a 4-week IHE intervention at the intervals after their [Hb] dropped for 10% or more during their training season. IHE intervention lasted 1 h and took place once a day and five times a week. Hematological and hormonal parameters, including [Hb], red blood cells (RBC), hematocrit (Hct), reticulocytes, serum erythropoietin (EPO), testosterone (T) and cortisol (C) were examined. After the IHE intervention was launched, [Hb], RBC and Hct of the subjects were increased progressively with their maximum levels (P < 0.01) showing at the third or fourth week, respectively. An increase in reticulocyte count (P < 0.01) suggests that IHE intervention promotes erythropoiesis to increase [Hb]. Besides, serum level of EPO, the hormone known to stimulate erythropoiesis, was overall higher than that before the IHE intervention, although it was statistically insignificant. Furthermore, the serum level of T, another hormone known to stimulate erythropoiesis, was increased progressively with the maximum level showing at the fourth week. Collectively, this study further confirms that IHE intervention may be used as a new strategy to prevent intense exercise training-induced reductions in [Hb].