Impact of physical activity on red blood cell osmotic stability and deformability

Abstract

Introduction The membrane of red blood cells (RBCs) plays a crucial role in determining their functional characteristics. During exercise, RBCs undergo various mechanical and biochemical adaptations that affect their membrane characteristics and can influence whole blood rheology and perfusion dynamics [1]. In this pilot study, we investigated the effects of exercise on RBC membrane characteristics in athletes compared to healthy sedentary individuals, using deformability and osmotic fragility tests. Methods Red blood cells were isolated from the venous blood of five basketball players and age-matched healthy sedentary controls. The athletes’ blood was collected at three different time points: immediately after training (IAT), 24 hours after training (24h), and 48 hours after training (48h). Osmotic fragility was determined by exposing RBCs to decreasing concentrations of NaCl solution and measuring the optical density (OD540) of the released hemoglobin. Using ektacytometry measurements, the RBC deformability was obtained as a function of shear stress and elongation index, and the data was fitted using Hill’s function. Results and Discussion The osmotic fragility test revealed a lower half-maximal hemolytic (H50) value (% of NaCl) for athletes (IAT= 0.35, 24h = 0.34, and 48h = 0.37) compared to control (0.41). Additionally, we found that athletes’ RBCs exhibited greater responsiveness to deformation under increasing shear stress, confirmed by the higher Hill’s coefficient (slope) value and lower half-maximal shear-stress values (K coefficient) of the deformability curves (IAE = 3.09, 24h = 2, 48h = 2.17 and CTRL = 9.35). These results reflect RBC specific adaptative response in athletes at three different time points and between the athletes and sedentary controls [2]. Conclusions These results highlight differences in osmotic stability and deformation response of RBCs between athletes and controls in favor of exercise in maintaining optimal RBC function, oxygen delivery, and overall circulatory health, offering potential therapeutic benefits