Blood sampling and analyses
sweat loss, mass loss, Sweat loss
BLOOD
During each trial, venous blood samples were obtained from an indwelling catheter (22G, Becton Dickenson, Madrid, Spain) in an antecubital vein. Blood was drawn every 30 min during, and upon completion of, exercise. In total, during each experiment, ~ 30 ml of blood was drawn. Blood samples were analyzed immediately for sodium (GEM Premier 3000, Instrumentation Laboratory, Bedford, USA) and hematocrit and hemoglobin (OSM 3, Radiometer Medical, Brønshøj, DK). Changes in plasma volume (PV) were calculated according to Dill and Costill (Dill and Costill Sweat loss was estimated by change in body mass corrected for mass loss from toileting and fluid intake. Rates of sweat loss were calculated by dividing by exercise time.