Blood collection
BLOOD, FRANKLIN
Blood was collected at four timepoints on T1 and T2: prior to the initiation of any exercise (timepoint A), within 10 min following HIE (timepoint B), 30 min post-exercise (timepoint C), and 60 min post-exercise (timepoint D). The first blood draws occurred following a 10 min rest in a seated position. A venous catheter (Becton, Dickinson, and Company, Franklin Lakes, NJ, USA) was inserted into the antecubital vein and was used for all four blood draws. One participant (female) was excluded from blood analysis due to inability to retrieve sufficient blood from her veins; however, she was included in HIE performance analysis.Approximately 25 mL of blood was drawn at every timepoint for approximately 100 mL of blood drawn per testing session using a serum separator tube (SST) and two dipotassium ethylenediaminetetraacetic acid tubes (K2EDTA; Becton, Dickinson & Co., Franklin Lakes, NJ, USA). The K2EDTA tubes were sent to a CLIA-certified laboratory (Bio-Reference Laboratories, Inc.; Elmwood Park, NJ, USA) for whole blood and immune system analysis within 24 h of collection. Blood composition analysis included total white blood cell count (WBC), red blood cell count (RBC), hemoglobin (HGB), hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), MCH concentration (MCHC), RBC distribution width (RDW), platelet count, and mean platelet volume (MPV). HGB and HCT were used as a standard to calculate plasma value shifts with acute exercise and therefore are not presented in the results. The immune marker panel included leukocyte concentrations of neutrophils, lymphocytes, monocytes, eosinophils, basophils, natural killer cells (CD16 + CD56) (NKC), T-lymphocytes (CD3), and B- lymphocytes (CD19). The panel also included the concentrations of T-helper cells, which present CD4 glycoproteins (CD4 cells), and SST vials were allowed to stand for 30 min following collection and inversion, prior to processing where vials were centrifuged for 15 min at 3300×