ABSTRACT
This study evaluated the effects of 2 different types of acute aerobic exercise on the osmotic stability of human erythrocyte membrane and on different hematological and biochemical variables that are associated with this membrane property. The study population consisted of 20 healthy and active men. Participants performed single sessions of 2 types of exercise. The first session consisted of 60 min of moderate-intensity continuous exercise (MICE). The second session, executed a week later, consisted of high-intensity interval exercise (HIIE) until exhaustion. The osmotic stability of the erythrocyte membrane was represented by the inverse of the salt concentration (1/H50) at the midpoint of the sigmoidal curve of dependence between the absorbance of hemoglobin and the NaCl concentration. The values of 1/H50 changed from 2.29±0.1 to 2.33±0.09 after MICE and from 2.30±0.08 to 2.23±0.12 after HIIE. During MICE mean corpuscular volume increased, probably due to in vivo lysis of older erythrocytes, with preservation of cells that were larger and more resistant to in vitro lysis. The study showed that a single bout of acute exercise affected erythrocyte stability, which increased after MICE and decreased after HIIE.
