Hypoxic Exercise Training Improved Gardos Channel‐Mediated Erythrocyte Deformability

Abstract

Erythrocyte deformability is an important player in blood rheology. Gardos channel (Ca2+‐activated K+ channel) regulates erythrocyte deformability by employing the ions‐mediated cytoskeleton proteins. This study investigated whether hypoxic exercise training affects Gardos channel‐mediated erythrocyte deformability and further explores its underlying mechanisms. Ten sedentary males were trained on a bicycle ergometer at 60%VO2max under 15%O2 air condition for 30 minutes per day, 5 days per week for 5 weeks. Erythrocyte deformability was determined by dynamic flow ektacytometer, whereas erythrocyte cell volume, Gardos channel performance, and cytoskeleton protein levels were evaluated by the flow cytometry. Our results demonstrated that at pre‐training stage, acute 12%O2 exercise declined erythrocyte deformability mediated by Gardos channel, which was accompanied by erythrocyte shrinkage and decreases in sprectrin and actin levels of erythrocytes. However, 5 weeks of 15%O2 exercise training enhanced Gardos channel‐mediated erythrocyte deformability and increased erythrocyte cytoskeleton protein levels at rest and following acute 12%O2 exercise. Therefore, we conclude that long‐term moderate‐intensity exercise at 15%O2 environment increases erythrocyte deformability under shear flow, possibly by improving performance of Gardos channel on erythrocyte.