Acute alterations in the hematological and hemorheological profile induced by resistance training and possible implication for microvascular functionality

Depending on the exercise variables and training design, resistance exercise can be applied to gain muscle mass, prevent diseases like osteoporosis and sarcopenia or generally increase strength capacity. But the influence on blood flow parameters and possible consequences in health and disease are less understood. To examine the possible impact of resistance exercise of different duration on hemorheology, oxidative stress and microvascular function, participants (n = 6) performed lower-limb resistance exercise of the quadriceps femoris. Loading consisted of 1 (S1), 5 (S5) and 10 (S10) sets, on separated days, at the individual 10 repetition maximum. Blood samples were taken before (Pre) and after (Post0) each set as well after a 25-min recovery period (Post25). Hemograms were measured to analyze hematocrit, white blood cell (WBC) count and red blood cell (RBC) count. RBC deformability and aggregation were measured by ektacytometry and syllectometry to determine hemorheological responses. Plasma and RBC nitrate were measured by chemiluminescence detection to determine nitric oxide production. Formation of N-tyrosine and plasma malondialdehyde to determine oxidative stress and lipid peroxidation were measured by immunostaining and ELISA, respectively. Hematocrit, RBC, WBC count and aggregation increased Post0 in each protocol with subsequently decreased values Post25 below Pre values. High effect size was observed regarding deformability during the different sets. RBC nitrite analysis revealed effect size alterations between the trainings, whereas plasma nitrite was not affected. Effects size was evident in lipid peroxidation, whereas N-tyrosine concentration was not altered. Lower-limb resistance exercise induced acute changes in hematological and hemorheological parameters, whereby intermittent hemodilution and plasma shifts seemed the major contributor. The acute adaptations of RBC function seen during short duration resistance exercise might contribute to beneficial effects on microvascular circulation with a low oxidative stress response.