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September 1976

Morphological Features of Red Blood Cells in Subjects With Sickle Cell Trait: Changes During Exercise

Author Affiliations

From the Harvard Medical Unit, Boston City Hospital, and the Department of Medicine, Harvard Medical School, Boston.

Arch Intern Med. 1976;136(9):1064-1066. doi:10.1001/archinte.1976.03630090086021

Occasional complications and even death in subjects with sickle cell trait have been attributed to severe physical exertion. However, the extent to which sickling actually occurs during exercise has not been reported. This study examined the red blood cell morphological features immediately following near maximal upright graded bicycle exercise in five asymptomatic black subjects with hemoglobin AS. Exercise produced minimal sickling in vivo, which was not proportional to the intensity of exercise. The amount of sickling in vivo was small in comparison to that observed in the presence of severe hypoxia in vitro, never exceeding 0.75%. In seven normal subjects with hemoglobin AA, exercise did not cause changes in red blood cell morphological features. We conclude that exercise may initiate sickling in subjects with sickle cell trait.

(Arch Intern Med 136:1064-1066, 1976)