Purpose: This study investigated hemorheological parameters in response to exercise in sickle cell trait (SCT) athletes with or without [alpha]-thalassemia Methods: Six athletes with SCT (HbAS), 7 athletes with SCT and [alpha]-thalassemia (HbASAT), and 10 control athletes (HbAA) performed a progressive and maximal exercise test on cycloergometer. Blood viscosity ([eta]b), plasma viscosity ([eta]p), [eta]b at corrected hematocrit ([eta]b45), hematocrit (Hct), and red blood cell (RBC) rigidity were assessed at rest, at maximal exercise and 24 h after exercise Results: [eta]b and [eta]p were not different between the three groups at any time. Exercise induced changes in [eta]b in HbAA and HbASAT groups but not in HbAS group. [eta]b45 was higher in HbAS group compared with the other groups (P < 0.05), at rest and 24 h after exercise and increased only in HbAA group in response to exercise. HbAS group had lower Hct than HbAA group at any time. Hct and [eta]p increased after exercise and declined under baseline values 24 h after exercise in all groups. RBC rigidity was higher in HbAS group compared with HbAA and HbASAT groups at any time, and was lower and higher at maximal exercise and 24 h after exercise, respectively, in all groups compared with resting values Conclusions: These results demonstrate that HbAS group is prone to higher RBC rigidity, which might lead to hemorheological alterations that are thought to participate to microcirculation disorders. However, these alterations are limited by the coexistence of [alpha]-thalassemia. Moreover, hemorheological parameters were not further impaired in SCT athletes with or without [alpha]-thalassemia in response to exercise. Training status might be protective from physiological stresses usually leading to sickling process in SCT carriers.
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